feat(server): API relay gateway backend M0-M4

Gin + GORM + pure-Go SQLite. Users/auth (JWT), API key management with
quotas, proxy gateway with weighted channel failover and health checks,
usage/billing ledger, cross-protocol conversion (Anthropic Messages /
OpenAI Chat Completions / OpenAI Responses), and channel/model admin API.
Channels declare native API formats and auto-convert the rest.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

server/cmd/server/main.go

@@ -0,0 +1,188 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/admin"
+	"openteam/server/internal/apikey"
+	"openteam/server/internal/billing"
+	"openteam/server/internal/channel"
+	"openteam/server/internal/config"
+	"openteam/server/internal/pkg/password"
+	"openteam/server/internal/proxy"
+	"openteam/server/internal/recharge"
+	"openteam/server/internal/store"
+	"openteam/server/internal/usage"
+	"openteam/server/internal/user"
+)
+
+func main() {
+	cfg := config.Load()
+
+	zapCfg := zap.NewProductionConfig()
+	if cfg.Debug {
+		zapCfg.Level = zap.NewAtomicLevelAt(zap.DebugLevel)
+	}
+	logger, err := zapCfg.Build()
+	if err != nil {
+		log.Fatalf("init logger: %v", err)
+	}
+	defer logger.Sync()
+	logger.Info("starting openteam server", zap.String("env", cfg.Env), zap.String("db", cfg.DB.Driver))
+
+	db, err := store.Open(cfg.DB.Driver, cfg.DB.DSN, cfg.Debug)
+	if err != nil {
+		logger.Fatal("open database", zap.Error(err))
+	}
+	if err := store.Migrate(db); err != nil {
+		logger.Fatal("migrate database", zap.Error(err))
+	}
+	seedAdmin(db, cfg, logger)
+
+	// Services.
+	userSvc := user.NewService(db, cfg, logger)
+	keySvc := apikey.NewService(db, logger)
+	billSvc := billing.NewService(db, logger)
+	usageSvc := usage.NewService(db, logger)
+	channelSvc := channel.NewService(db, cfg, logger)
+	gw := proxy.NewGateway(db, cfg, logger, channelSvc, billSvc, usageSvc, keySvc)
+
+	// Background tasks.
+	channelSvc.StartHealthCheck()
+	go periodicRecoverCooldown(channelSvc, cfg)
+
+	// Router.
+	gin.SetMode(gin.ReleaseMode)
+	if cfg.Debug {
+		gin.SetMode(gin.DebugMode)
+	}
+	r := gin.New()
+	r.Use(gin.Logger(), gin.Recovery(), corsMiddleware(cfg))
+
+	// Public proxy endpoints (Bearer API key auth handled inside the gateway).
+	for _, route := range proxy.Routes {
+		r.POST(route.UpstreamPath, gw.Handle(route))
+	}
+	modelsHandler := proxy.NewModelsHandler(db, gw)
+	r.GET("/v1/models", modelsHandler.List)
+
+	// Management API.
+	api := r.Group("/api/v1")
+	{
+		auth := api.Group("/auth")
+		auth.POST("/register", userH(userSvc, cfg, logger).Register)
+		auth.POST("/login", userH(userSvc, cfg, logger).Login)
+		auth.POST("/refresh", userH(userSvc, cfg, logger).Refresh)
+		auth.POST("/logout", userH(userSvc, cfg, logger).Logout)
+		auth.GET("/me", userSvc.Middleware(cfg.Auth.JWTSecret), userH(userSvc, cfg, logger).Me)
+
+		userGroup := api.Group("", userSvc.Middleware(cfg.Auth.JWTSecret))
+		userGroup.GET("/user/profile", userH(userSvc, cfg, logger).Profile)
+		userGroup.GET("/user/balance", userH(userSvc, cfg, logger).Balance)
+
+		keyH := apikey.NewHandler(keySvc, logger)
+		userGroup.GET("/keys", keyH.List)
+		userGroup.POST("/keys", keyH.Create)
+		userGroup.PATCH("/keys/:id", keyH.Update)
+		userGroup.DELETE("/keys/:id", keyH.Delete)
+
+		usageH := usage.NewHandler(db, logger)
+		userGroup.GET("/usage/summary", usageH.Summary)
+		userGroup.GET("/usage/stats", usageH.Stats)
+		userGroup.GET("/usage/logs", usageH.Logs)
+
+		rechargeH := recharge.NewHandler(db, logger)
+		userGroup.POST("/recharges", rechargeH.Create)
+		userGroup.GET("/recharges", rechargeH.List)
+
+		admin.Register(api.Group("/admin", userSvc.Middleware(cfg.Auth.JWTSecret)), db, channelSvc, billSvc, logger)
+	}
+
+	srv := &http.Server{
+		Addr:              ":" + cfg.HTTPPort,
+		Handler:           r,
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+	logger.Info("listening", zap.String("addr", srv.Addr))
+	if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		logger.Fatal("server error", zap.Error(err))
+	}
+}
+
+func userH(svc *user.Service, cfg *config.Config, logger *zap.Logger) *user.Handler {
+	return user.NewHandler(svc, cfg, logger)
+}
+
+// seedAdmin creates the initial admin account from env vars, if configured.
+func seedAdmin(db *gorm.DB, cfg *config.Config, logger *zap.Logger) {
+	username := os.Getenv("ADMIN_USERNAME")
+	adminPass := os.Getenv("ADMIN_PASSWORD")
+	if username == "" || adminPass == "" {
+		return
+	}
+	var count int64
+	db.Model(&store.User{}).Where("role = ?", "admin").Count(&count)
+	if count > 0 {
+		return
+	}
+	hash, err := password.Hash(adminPass)
+	if err != nil {
+		logger.Warn("seed admin: hash failed", zap.Error(err))
+		return
+	}
+	admin := &store.User{
+		Username:     username,
+		Email:        username + "@admin.local",
+		PasswordHash: hash,
+		Role:         "admin",
+		Balance:      decimalZero(),
+		Status:       "active",
+	}
+	if err := db.Create(admin).Error; err != nil {
+		logger.Warn("seed admin: create failed", zap.Error(err))
+		return
+	}
+	logger.Info("seeded admin account", zap.String("username", username))
+}
+
+func decimalZero() decimal.Decimal {
+	return decimal.NewFromInt(0)
+}
+
+func periodicRecoverCooldown(ch *channel.Service, cfg *config.Config) {
+	ticker := time.NewTicker(cfg.HealthCheck.Interval)
+	defer ticker.Stop()
+	for range ticker.C {
+		ch.RecoverCooldown()
+	}
+}
+
+func corsMiddleware(cfg *config.Config) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		origin := c.GetHeader("Origin")
+		allowed := "*"
+		for _, o := range cfg.AllowOrigins {
+			if o == "*" || o == origin {
+				allowed = o
+				break
+			}
+		}
+		c.Header("Access-Control-Allow-Origin", allowed)
+		c.Header("Access-Control-Allow-Credentials", "true")
+		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
+		c.Header("Access-Control-Allow-Headers", "Content-Type, Authorization")
+		if c.Request.Method == http.MethodOptions {
+			c.AbortWithStatus(http.StatusNoContent)
+			return
+		}
+		c.Next()
+	}
+}

server/go.mod

@@ -0,0 +1,58 @@
+module openteam/server
+
+go 1.26.5
+
+require (
+	github.com/bytedance/gopkg v0.1.3 // indirect
+	github.com/bytedance/sonic v1.15.0 // indirect
+	github.com/bytedance/sonic/loader v0.5.0 // indirect
+	github.com/cloudwego/base64x v0.1.6 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.12 // indirect
+	github.com/gin-contrib/sse v1.1.0 // indirect
+	github.com/gin-gonic/gin v1.12.0 // indirect
+	github.com/glebarez/go-sqlite v1.21.2 // indirect
+	github.com/glebarez/sqlite v1.11.0 // indirect
+	github.com/go-playground/locales v0.14.1 // indirect
+	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-playground/validator/v10 v10.30.1 // indirect
+	github.com/goccy/go-json v0.10.5 // indirect
+	github.com/goccy/go-yaml v1.19.2 // indirect
+	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.10.0 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
+	github.com/leodido/go-urn v1.4.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/quic-go/qpack v0.6.0 // indirect
+	github.com/quic-go/quic-go v0.59.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	github.com/shopspring/decimal v1.4.0 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	github.com/ugorji/go/codec v1.3.1 // indirect
+	go.mongodb.org/mongo-driver/v2 v2.5.0 // indirect
+	go.uber.org/multierr v1.10.0 // indirect
+	go.uber.org/zap v1.28.0 // indirect
+	golang.org/x/arch v0.22.0 // indirect
+	golang.org/x/crypto v0.55.0 // indirect
+	golang.org/x/net v0.57.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
+	golang.org/x/sys v0.47.0 // indirect
+	golang.org/x/text v0.41.0 // indirect
+	google.golang.org/protobuf v1.36.10 // indirect
+	gorm.io/driver/postgres v1.6.2 // indirect
+	gorm.io/gorm v1.31.2 // indirect
+	modernc.org/libc v1.22.5 // indirect
+	modernc.org/mathutil v1.5.0 // indirect
+	modernc.org/memory v1.5.0 // indirect
+	modernc.org/sqlite v1.23.1 // indirect
+)

server/go.sum

@@ -0,0 +1,124 @@
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+github.com/bytedance/gopkg v0.1.3/go.mod h1:576VvJ+eJgyCzdjS+c4+77QF3p7ubbtiKARP3TxducM=
+github.com/bytedance/sonic v1.15.0 h1:/PXeWFaR5ElNcVE84U0dOHjiMHQOwNIx3K4ymzh/uSE=
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+github.com/bytedance/sonic/loader v0.5.0 h1:gXH3KVnatgY7loH5/TkeVyXPfESoqSBSBEiDd5VjlgE=
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server/internal/admin/channels.go

@@ -0,0 +1,329 @@
+package admin
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/channel"
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+)
+
+type channelHandler struct {
+	db  *gorm.DB
+	ch  *channel.Service
+	log *zap.Logger
+}
+
+type channelInput struct {
+	Name           string   `json:"name" binding:"required"`
+	Provider       string   `json:"provider" binding:"omitempty,oneof=openai anthropic compatible"`
+	BaseURL        string   `json:"baseUrl" binding:"required"`
+	APIKey         string   `json:"apiKey"`
+	Weight         int      `json:"weight"`
+	Priority       int      `json:"priority"`
+	TimeoutMs      int      `json:"timeoutMs"`
+	MaxConcurrency int      `json:"maxConcurrency"`
+	Enabled        *bool    `json:"enabled"`
+	Formats        []string `json:"formats"`
+}
+
+// ListChannels handles GET /api/v1/admin/channels.
+func (h *channelHandler) List(c *gin.Context) {
+	var channels []store.Channel
+	if err := h.db.Order("id ASC").Find(&channels).Error; err != nil {
+		h.log.Warn("list channels failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list channels failed")
+		return
+	}
+	out := make([]gin.H, 0, len(channels))
+	for i := range channels {
+		out = append(out, channelDTO(&channels[i]))
+	}
+	httpx.OK(c, out)
+}
+
+// Create handles POST /api/v1/admin/channels.
+func (h *channelHandler) Create(c *gin.Context) {
+	var in channelInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	provider := in.Provider
+	if len(in.Formats) > 0 {
+		if err := validateFormats(in.Formats); err != nil {
+			httpx.Fail(c, http.StatusBadRequest, err.Error())
+			return
+		}
+		provider = deriveProvider(in.Formats)
+	}
+	if provider == "" {
+		provider = "openai"
+	}
+	enc, err := h.ch.EncryptKey(in.APIKey)
+	if err != nil {
+		httpx.Fail(c, http.StatusInternalServerError, "encrypt key failed")
+		return
+	}
+	ch := &store.Channel{
+		Name: in.Name, Provider: provider, BaseURL: in.BaseURL, Formats: in.Formats,
+		APIKeyEnc: enc, Weight: defaultIf(in.Weight, 1), Priority: in.Priority,
+		TimeoutMs: defaultIf(in.TimeoutMs, 300000), MaxConcurrency: defaultIf(in.MaxConcurrency, 100),
+		Enabled: true,
+	}
+	if in.Enabled != nil {
+		ch.Enabled = *in.Enabled
+	}
+	if err := h.db.Create(ch).Error; err != nil {
+		h.log.Warn("create channel failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create channel failed")
+		return
+	}
+	httpx.Created(c, channelDTO(ch))
+}
+
+// Update handles PUT /api/v1/admin/channels/:id.
+func (h *channelHandler) Update(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var ch store.Channel
+	if err := h.db.First(&ch, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "channel not found")
+		return
+	}
+	var in channelInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	updates := map[string]any{
+		"name": in.Name, "base_url": in.BaseURL,
+		"weight": defaultIf(in.Weight, ch.Weight), "priority": in.Priority,
+		"timeout_ms": defaultIf(in.TimeoutMs, ch.TimeoutMs),
+		"max_concurrency": defaultIf(in.MaxConcurrency, ch.MaxConcurrency),
+	}
+	if len(in.Formats) > 0 {
+		if err := validateFormats(in.Formats); err != nil {
+			httpx.Fail(c, http.StatusBadRequest, err.Error())
+			return
+		}
+		updates["provider"] = deriveProvider(in.Formats)
+		// GORM map updates skip the json serializer, so encode explicitly;
+		// a raw []string would be emitted as a SQL row-value list.
+		formatsJSON, err := json.Marshal(in.Formats)
+		if err != nil {
+			httpx.Fail(c, http.StatusInternalServerError, "serialize formats failed")
+			return
+		}
+		updates["formats"] = string(formatsJSON)
+	} else if in.Provider != "" {
+		updates["provider"] = in.Provider
+	}
+	if in.Enabled != nil {
+		updates["enabled"] = *in.Enabled
+	}
+	if in.APIKey != "" {
+		enc, err := h.ch.EncryptKey(in.APIKey)
+		if err != nil {
+			httpx.Fail(c, http.StatusInternalServerError, "encrypt key failed")
+			return
+		}
+		updates["api_key_enc"] = enc
+	}
+	if err := h.db.Model(&ch).Updates(updates).Error; err != nil {
+		h.log.Warn("update channel failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "update channel failed")
+		return
+	}
+	h.db.First(&ch, id)
+	httpx.OK(c, channelDTO(&ch))
+}
+
+// Delete handles DELETE /api/v1/admin/channels/:id.
+func (h *channelHandler) Delete(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	if err := h.db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Where("channel_id = ?", id).Delete(&store.ChannelModelBinding{}).Error; err != nil {
+			return err
+		}
+		return tx.Delete(&store.Channel{}, id).Error
+	}); err != nil {
+		h.log.Warn("delete channel failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "delete channel failed")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}
+
+// Test handles POST /api/v1/admin/channels/:id/test.
+func (h *channelHandler) Test(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var ch store.Channel
+	if err := h.db.First(&ch, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "channel not found")
+		return
+	}
+	ok, latency, model, err := h.ch.Test(&ch)
+	if err != nil || !ok {
+		msg := "test failed"
+		if err != nil {
+			msg = err.Error()
+		}
+		httpx.Fail(c, http.StatusBadGateway, msg)
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true, "latencyMs": latency, "model": model})
+}
+
+// ImportModels handles POST /api/v1/admin/channels/:id/import-models.
+func (h *channelHandler) ImportModels(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var ch store.Channel
+	if err := h.db.First(&ch, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "channel not found")
+		return
+	}
+	names, err := h.ch.ImportModels(&ch)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadGateway, "import failed: "+err.Error())
+		return
+	}
+	httpx.OK(c, gin.H{"imported": names, "count": len(names)})
+}
+
+// ListBindings handles GET /api/v1/admin/channels/:id/bindings.
+func (h *channelHandler) ListBindings(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var bindings []store.ChannelModelBinding
+	if err := h.db.Preload("Model").Where("channel_id = ?", id).Find(&bindings).Error; err != nil {
+		h.log.Warn("list bindings failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list bindings failed")
+		return
+	}
+	out := make([]gin.H, 0, len(bindings))
+	for _, b := range bindings {
+		out = append(out, gin.H{
+			"id": b.ID, "modelId": b.ModelID, "modelName": b.Model.Name,
+			"upstreamModel": b.UpstreamModel, "weight": b.Weight,
+		})
+	}
+	httpx.OK(c, out)
+}
+
+// SaveBindings handles PUT /api/v1/admin/channels/:id/bindings.
+func (h *channelHandler) SaveBindings(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var in struct {
+		Items []struct {
+			ModelID       int64  `json:"modelId"`
+			UpstreamModel string `json:"upstreamModel"`
+			Weight        int    `json:"weight"`
+		} `json:"items"`
+	}
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	if err := h.db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Where("channel_id = ?", id).Delete(&store.ChannelModelBinding{}).Error; err != nil {
+			return err
+		}
+		for _, item := range in.Items {
+			if item.ModelID == 0 {
+				continue
+			}
+			b := store.ChannelModelBinding{
+				ChannelID: id, ModelID: item.ModelID,
+				UpstreamModel: item.UpstreamModel, Weight: defaultIf(item.Weight, 1),
+			}
+			if err := tx.Create(&b).Error; err != nil {
+				return err
+			}
+		}
+		return nil
+	}); err != nil {
+		h.log.Warn("save bindings failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "save bindings failed")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}
+
+func channelDTO(ch *store.Channel) gin.H {
+	return gin.H{
+		"id": ch.ID, "name": ch.Name, "provider": ch.Provider, "baseUrl": ch.BaseURL,
+		"formats": ch.FormatsResolved(),
+		"weight": ch.Weight, "priority": ch.Priority, "timeoutMs": ch.TimeoutMs,
+		"maxConcurrency": ch.MaxConcurrency, "healthStatus": ch.HealthStatus,
+		"healthFailures": ch.HealthFailures, "enabled": ch.Enabled,
+		"createdAt": ch.CreatedAt, "updatedAt": ch.UpdatedAt,
+	}
+}
+
+var validFormats = map[string]bool{
+	store.FormatOpenAIChat:      true,
+	store.FormatOpenAIResponses: true,
+	store.FormatAnthropic:       true,
+}
+
+func validateFormats(fs []string) error {
+	for _, f := range fs {
+		if !validFormats[f] {
+			return fmt.Errorf("invalid api format: %s", f)
+		}
+	}
+	return nil
+}
+
+// deriveProvider computes the conversion-target provider from the declared
+// formats. Anthropic-only channels convert to Claude; anything else targets the
+// OpenAI chat-completions family.
+func deriveProvider(formats []string) string {
+	hasAnthropic, hasOpenAI := false, false
+	for _, f := range formats {
+		switch f {
+		case store.FormatAnthropic:
+			hasAnthropic = true
+		case store.FormatOpenAIChat, store.FormatOpenAIResponses:
+			hasOpenAI = true
+		}
+	}
+	if hasAnthropic && !hasOpenAI {
+		return "anthropic"
+	}
+	return "openai"
+}
+
+func defaultIf(v, def int) int {
+	if v == 0 {
+		return def
+	}
+	return v
+}

server/internal/admin/config.go

@@ -0,0 +1,57 @@
+package admin
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+)
+
+type configHandler struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+// Get handles GET /api/v1/admin/config — returns the full config map.
+func (h *configHandler) Get(c *gin.Context) {
+	var confs []store.SystemConfig
+	if err := h.db.Find(&confs).Error; err != nil {
+		h.log.Warn("load config failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "load config failed")
+		return
+	}
+	out := map[string]any{}
+	for _, conf := range confs {
+		var v any
+		if err := json.Unmarshal(conf.Value, &v); err == nil {
+			out[conf.Key] = v
+		}
+	}
+	httpx.OK(c, out)
+}
+
+// Put handles PUT /api/v1/admin/config — upserts key/value pairs.
+func (h *configHandler) Put(c *gin.Context) {
+	var in map[string]any
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	for k, v := range in {
+		raw, err := json.Marshal(v)
+		if err != nil {
+			continue
+		}
+		conf := store.SystemConfig{Key: k, Value: raw}
+		if err := h.db.Save(&conf).Error; err != nil {
+			h.log.Warn("save config failed", zap.Error(err), zap.String("key", k))
+			httpx.Fail(c, http.StatusInternalServerError, "save config failed")
+			return
+		}
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}

server/internal/admin/handler.go

@@ -0,0 +1,57 @@
+package admin
+
+import (
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/billing"
+	"openteam/server/internal/channel"
+	"openteam/server/internal/user"
+)
+
+// Register wires the admin routes onto a gin group.
+func Register(g *gin.RouterGroup, db *gorm.DB, ch *channel.Service, bill *billing.Service, log *zap.Logger) {
+	// Handler instances.
+	chHandler := &channelHandler{db: db, ch: ch, log: log}
+	modelHandler := &modelHandler{db: db, log: log}
+	userHandler := &userHandler{db: db, bill: bill, log: log}
+	usageHandler := &usageHandler{db: db, bill: bill, log: log}
+	configHandler := &configHandler{db: db, log: log}
+
+	g = g.Group("", user.RequireAdmin())
+
+	// Channels.
+	g.GET("/channels", chHandler.List)
+	g.POST("/channels", chHandler.Create)
+	g.PUT("/channels/:id", chHandler.Update)
+	g.DELETE("/channels/:id", chHandler.Delete)
+	g.POST("/channels/:id/test", chHandler.Test)
+	g.POST("/channels/:id/import-models", chHandler.ImportModels)
+	g.GET("/channels/:id/bindings", chHandler.ListBindings)
+	g.PUT("/channels/:id/bindings", chHandler.SaveBindings)
+
+	// Models.
+	g.GET("/models", modelHandler.List)
+	g.POST("/models", modelHandler.Create)
+	g.PUT("/models/:id", modelHandler.Update)
+	g.PUT("/models/:id/price", modelHandler.UpdatePrice)
+
+	// Users.
+	g.GET("/users", userHandler.List)
+	g.PATCH("/users/:id", userHandler.Update)
+	g.POST("/users/:id/balance", userHandler.AdjustBalance)
+
+	// Recharges (reserved; approve/reject wire the paused state machine).
+	g.GET("/recharges", usageHandler.Recharges)
+	g.POST("/recharges/:id/approve", usageHandler.ApproveRecharge)
+	g.POST("/recharges/:id/reject", usageHandler.RejectRecharge)
+
+	// Usage & stats.
+	g.GET("/usage", usageHandler.Usage)
+	g.GET("/stats/overview", usageHandler.Overview)
+
+	// System config.
+	g.GET("/config", configHandler.Get)
+	g.PUT("/config", configHandler.Put)
+}

server/internal/admin/models.go

@@ -0,0 +1,171 @@
+package admin
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+)
+
+type modelHandler struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+type modelInput struct {
+	Name            string `json:"name" binding:"required"`
+	DisplayName     string `json:"displayName"`
+	InputPrice      string `json:"inputPrice"`
+	OutputPrice     string `json:"outputPrice"`
+	CacheReadPrice  string `json:"cacheReadPrice"`
+	Enabled         *bool  `json:"enabled"`
+	Sort            *int   `json:"sort"`
+}
+
+// List handles GET /api/v1/admin/models.
+func (h *modelHandler) List(c *gin.Context) {
+	var models []store.Model
+	if err := h.db.Order("sort ASC, id ASC").Find(&models).Error; err != nil {
+		h.log.Warn("list models failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list models failed")
+		return
+	}
+	out := make([]gin.H, 0, len(models))
+	for i := range models {
+		out = append(out, modelDTO(&models[i]))
+	}
+	httpx.OK(c, out)
+}
+
+// Create handles POST /api/v1/admin/models.
+func (h *modelHandler) Create(c *gin.Context) {
+	var in modelInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	m := &store.Model{
+		Name:        in.Name,
+		DisplayName: in.DisplayName,
+		InputPrice:      parsePrice(in.InputPrice),
+		OutputPrice:     parsePrice(in.OutputPrice),
+		CacheReadPrice:  parsePrice(in.CacheReadPrice),
+		Enabled:         true,
+	}
+	if in.Enabled != nil {
+		m.Enabled = *in.Enabled
+	}
+	if in.Sort != nil {
+		m.Sort = *in.Sort
+	}
+	if err := h.db.Create(m).Error; err != nil {
+		h.log.Warn("create model failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create model failed")
+		return
+	}
+	httpx.Created(c, modelDTO(m))
+}
+
+// Update handles PUT /api/v1/admin/models/:id.
+func (h *modelHandler) Update(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid model id")
+		return
+	}
+	var m store.Model
+	if err := h.db.First(&m, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "model not found")
+		return
+	}
+	var in modelInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	updates := map[string]any{
+		"name": in.Name,
+	}
+	if in.DisplayName != "" {
+		updates["display_name"] = in.DisplayName
+	}
+	if in.InputPrice != "" {
+		updates["input_price"] = parsePrice(in.InputPrice)
+	}
+	if in.OutputPrice != "" {
+		updates["output_price"] = parsePrice(in.OutputPrice)
+	}
+	if in.CacheReadPrice != "" {
+		updates["cache_read_price"] = parsePrice(in.CacheReadPrice)
+	}
+	if in.Enabled != nil {
+		updates["enabled"] = *in.Enabled
+	}
+	if in.Sort != nil {
+		updates["sort"] = *in.Sort
+	}
+	if err := h.db.Model(&m).Updates(updates).Error; err != nil {
+		h.log.Warn("update model failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "update model failed")
+		return
+	}
+	h.db.First(&m, id)
+	httpx.OK(c, modelDTO(&m))
+}
+
+// UpdatePrice handles PUT /api/v1/admin/models/:id/price.
+func (h *modelHandler) UpdatePrice(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid model id")
+		return
+	}
+	var in struct {
+		InputPrice     string `json:"inputPrice"`
+		OutputPrice    string `json:"outputPrice"`
+		CacheReadPrice string `json:"cacheReadPrice"`
+	}
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	updates := map[string]any{}
+	if in.InputPrice != "" {
+		updates["input_price"] = parsePrice(in.InputPrice)
+	}
+	if in.OutputPrice != "" {
+		updates["output_price"] = parsePrice(in.OutputPrice)
+	}
+	if in.CacheReadPrice != "" {
+		updates["cache_read_price"] = parsePrice(in.CacheReadPrice)
+	}
+	if len(updates) == 0 {
+		httpx.Fail(c, http.StatusBadRequest, "no price fields provided")
+		return
+	}
+	res := h.db.Model(&store.Model{}).Where("id = ?", id).Updates(updates)
+	if res.RowsAffected == 0 {
+		httpx.Fail(c, http.StatusNotFound, "model not found")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}
+
+func parsePrice(s string) decimal.Decimal {
+	d, err := decimal.NewFromString(s)
+	if err != nil {
+		return decimal.Zero
+	}
+	return d.Round(8)
+}
+
+func modelDTO(m *store.Model) gin.H {
+	return gin.H{
+		"id": m.ID, "name": m.Name, "displayName": m.DisplayName,
+		"inputPrice": m.InputPrice.String(), "outputPrice": m.OutputPrice.String(),
+		"cacheReadPrice": m.CacheReadPrice.String(), "enabled": m.Enabled, "sort": m.Sort,
+	}
+}

server/internal/admin/usage.go

@@ -0,0 +1,222 @@
+package admin
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/billing"
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+	"openteam/server/internal/user"
+)
+
+type usageHandler struct {
+	db   *gorm.DB
+	bill *billing.Service
+	log  *zap.Logger
+}
+
+// Overview handles GET /api/v1/admin/stats/overview.
+func (h *usageHandler) Overview(c *gin.Context) {
+	now := time.Now()
+	today := now.Format("2006-01-02")
+	month := now.Format("2006-01-02")
+
+	var totals struct {
+		Requests int
+		Cost     decimal.Decimal
+	}
+	h.db.Model(&store.UsageDaily{}).
+		Select("COALESCE(SUM(requests),0) as requests, COALESCE(SUM(cost),0) as cost").
+		Scan(&totals)
+
+	var todayAgg struct {
+		Requests    int
+		Cost        decimal.Decimal
+		InputTokens int64
+		OutputTokens int64
+	}
+	h.db.Model(&store.UsageDaily{}).Where("date = ?", today).
+		Select("COALESCE(SUM(requests),0) as requests, COALESCE(SUM(cost),0) as cost, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens").
+		Scan(&todayAgg)
+
+	var monthAgg struct {
+		Requests int
+		Cost     decimal.Decimal
+	}
+	h.db.Model(&store.UsageDaily{}).Where("date >= ? AND date <= ?", month[:7]+"-01", today).
+		Select("COALESCE(SUM(requests),0) as requests, COALESCE(SUM(cost),0) as cost").
+		Scan(&monthAgg)
+
+	var userCount, channelCount, modelCount int64
+	h.db.Model(&store.User{}).Count(&userCount)
+	h.db.Model(&store.Channel{}).Count(&channelCount)
+	h.db.Model(&store.Model{}).Count(&modelCount)
+
+	httpx.OK(c, gin.H{
+		"total": gin.H{
+			"requests": totals.Requests,
+			"cost":     totals.Cost.String(),
+			"users":    userCount,
+			"channels": channelCount,
+			"models":   modelCount,
+		},
+		"today": gin.H{
+			"requests":     todayAgg.Requests,
+			"cost":         todayAgg.Cost.String(),
+			"inputTokens":  todayAgg.InputTokens,
+			"outputTokens": todayAgg.OutputTokens,
+		},
+		"month": gin.H{
+			"requests": monthAgg.Requests,
+			"cost":     monthAgg.Cost.String(),
+		},
+	})
+}
+
+// Usage handles GET /api/v1/admin/usage?from&to&userId&model&group=day|model|user.
+func (h *usageHandler) Usage(c *gin.Context) {
+	from := c.Query("from")
+	to := c.Query("to")
+	group := c.DefaultQuery("group", "day")
+
+	q := h.db.Model(&store.UsageDaily{})
+	if from != "" {
+		q = q.Where("date >= ?", from)
+	}
+	if to != "" {
+		q = q.Where("date <= ?", to)
+	}
+	if uid := c.Query("userId"); uid != "" {
+		q = q.Where("user_id = ?", uid)
+	}
+	if m := c.Query("model"); m != "" {
+		q = q.Where("model_id = ?", m)
+	}
+
+	var rows []struct {
+		Key          string `gorm:"column:g"`
+		Requests     int
+		InputTokens  int64
+		OutputTokens int64
+		Cost         decimal.Decimal
+	}
+	switch group {
+	case "model":
+		q = q.Joins("JOIN models ON models.id = usage_dailies.model_id").
+			Select("models.name as g, COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+			Group("models.name")
+	case "user":
+		q = q.Joins("JOIN users ON users.id = usage_dailies.user_id").
+			Select("users.username as g, COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+			Group("users.username")
+	default:
+		q = q.Select("date as g, COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+			Group("date").Order("date ASC")
+	}
+	if err := q.Scan(&rows).Error; err != nil {
+		h.log.Warn("admin usage query failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "usage query failed")
+		return
+	}
+	out := make([]gin.H, 0, len(rows))
+	for _, r := range rows {
+		out = append(out, gin.H{
+			"key": r.Key, "requests": r.Requests,
+			"inputTokens": r.InputTokens, "outputTokens": r.OutputTokens,
+			"cost": r.Cost.String(),
+		})
+	}
+	httpx.OK(c, out)
+}
+
+// Recharges handles GET /api/v1/admin/recharges.
+func (h *usageHandler) Recharges(c *gin.Context) {
+	status := c.Query("status")
+	q := h.db.Preload("User").Model(&store.RechargeOrder{})
+	if status != "" {
+		q = q.Where("status = ?", status)
+	}
+	var orders []store.RechargeOrder
+	if err := q.Order("id DESC").Limit(100).Find(&orders).Error; err != nil {
+		h.log.Warn("list recharges failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list recharges failed")
+		return
+	}
+	out := make([]gin.H, 0, len(orders))
+	for i := range orders {
+		o := &orders[i]
+		out = append(out, gin.H{
+			"id": o.ID, "userId": o.UserID, "username": o.User.Username,
+			"amount": o.Amount.String(), "status": o.Status, "method": o.Method,
+			"remark": o.Remark, "createdAt": o.CreatedAt,
+		})
+	}
+	httpx.OK(c, out)
+}
+
+// ApproveRecharge handles POST /api/v1/admin/recharges/:id/approve.
+func (h *usageHandler) ApproveRecharge(c *gin.Context) {
+	h.decideRecharge(c, "approve")
+}
+
+// RejectRecharge handles POST /api/v1/admin/recharges/:id/reject.
+func (h *usageHandler) RejectRecharge(c *gin.Context) {
+	h.decideRecharge(c, "reject")
+}
+
+func (h *usageHandler) decideRecharge(c *gin.Context, action string) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid order id")
+		return
+	}
+	admin := user.Current(c)
+
+	var order store.RechargeOrder
+	if err := h.db.First(&order, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "order not found")
+		return
+	}
+	if order.Status != "pending" {
+		httpx.Fail(c, http.StatusBadRequest, "order already processed")
+		return
+	}
+
+	var in struct {
+		Remark string `json:"remark"`
+	}
+	_ = c.ShouldBindJSON(&in)
+
+	now := time.Now()
+	if action == "approve" {
+		err = h.db.Transaction(func(tx *gorm.DB) error {
+			if _, cerr := h.bill.Credit(order.UserID, order.Amount, "recharge", orderIDStr(order.ID)); cerr != nil {
+				return cerr
+			}
+			return tx.Model(&order).Updates(map[string]any{
+				"status": "credited", "reviewed_by": admin.ID, "reviewed_at": now, "remark": in.Remark,
+			}).Error
+		})
+	} else {
+		err = h.db.Model(&order).Updates(map[string]any{
+			"status": "rejected", "reviewed_by": admin.ID, "reviewed_at": now, "remark": in.Remark,
+		}).Error
+	}
+	if err != nil {
+		h.log.Warn("recharge decision failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "recharge decision failed")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true, "status": order.Status})
+}
+
+func orderIDStr(id int64) string {
+	return strconv.FormatInt(id, 10)
+}

server/internal/admin/users.go

@@ -0,0 +1,140 @@
+package admin
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/billing"
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+)
+
+type userHandler struct {
+	db     *gorm.DB
+	bill   *billing.Service
+	log    *zap.Logger
+}
+
+// List handles GET /api/v1/admin/users?page&search.
+func (h *userHandler) List(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	if page < 1 {
+		page = 1
+	}
+	pageSize := 20
+	search := c.Query("search")
+
+	q := h.db.Model(&store.User{})
+	if search != "" {
+		like := "%" + search + "%"
+		q = q.Where("username LIKE ? OR email LIKE ?", like, like)
+	}
+	var total int64
+	q.Count(&total)
+
+	var users []store.User
+	if err := q.Order("id DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&users).Error; err != nil {
+		h.log.Warn("list users failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list users failed")
+		return
+	}
+	out := make([]gin.H, 0, len(users))
+	for i := range users {
+		out = append(out, userDTO(&users[i]))
+	}
+	httpx.OK(c, gin.H{"total": total, "page": page, "items": out})
+}
+
+// Update handles PATCH /api/v1/admin/users/:id.
+func (h *userHandler) Update(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid user id")
+		return
+	}
+	var u store.User
+	if err := h.db.First(&u, id).Error; err != nil {
+		httpx.Fail(c, http.StatusNotFound, "user not found")
+		return
+	}
+	var in struct {
+		Role   *string `json:"role"`
+		Status *string `json:"status"`
+	}
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	updates := map[string]any{}
+	if in.Role != nil {
+		if *in.Role != "admin" && *in.Role != "user" {
+			httpx.Fail(c, http.StatusBadRequest, "invalid role")
+			return
+		}
+		updates["role"] = *in.Role
+	}
+	if in.Status != nil {
+		if *in.Status != "active" && *in.Status != "disabled" {
+			httpx.Fail(c, http.StatusBadRequest, "invalid status")
+			return
+		}
+		updates["status"] = *in.Status
+	}
+	if len(updates) > 0 {
+		if err := h.db.Model(&u).Updates(updates).Error; err != nil {
+			h.log.Warn("update user failed", zap.Error(err))
+			httpx.Fail(c, http.StatusInternalServerError, "update user failed")
+			return
+		}
+	}
+	h.db.First(&u, id)
+	httpx.OK(c, userDTO(&u))
+}
+
+// AdjustBalance handles POST /api/v1/admin/users/:id/balance.
+func (h *userHandler) AdjustBalance(c *gin.Context) {
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid user id")
+		return
+	}
+	var in struct {
+		Amount string `json:"amount" binding:"required"`
+		Remark string `json:"remark"`
+	}
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	amount, err := decimal.NewFromString(in.Amount)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid amount")
+		return
+	}
+	if amount.IsZero() {
+		httpx.Fail(c, http.StatusBadRequest, "amount must be non-zero")
+		return
+	}
+	after, err := h.bill.AdminAdjust(id, amount.Round(8), in.Remark)
+	if err != nil {
+		if err == billing.ErrInsufficientBalance {
+			httpx.Fail(c, http.StatusBadRequest, "amount would make balance negative")
+			return
+		}
+		h.log.Warn("adjust balance failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "adjust balance failed")
+		return
+	}
+	httpx.OK(c, gin.H{"balanceAfter": after.String()})
+}
+
+func userDTO(u *store.User) gin.H {
+	return gin.H{
+		"id": u.ID, "username": u.Username, "email": u.Email,
+		"role": u.Role, "balance": u.Balance.String(), "status": u.Status,
+		"lastLoginAt": u.LastLoginAt, "createdAt": u.CreatedAt,
+	}
+}

server/internal/apikey/handler.go

@@ -0,0 +1,99 @@
+package apikey
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/user"
+)
+
+type Handler struct {
+	svc *Service
+	log *zap.Logger
+}
+
+func NewHandler(svc *Service, log *zap.Logger) *Handler {
+	return &Handler{svc: svc, log: log}
+}
+
+// List handles GET /api/v1/keys.
+func (h *Handler) List(c *gin.Context) {
+	u := user.Current(c)
+	keys, err := h.svc.List(u.ID)
+	if err != nil {
+		h.log.Warn("list keys failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list keys failed")
+		return
+	}
+	out := make([]map[string]any, 0, len(keys))
+	for i := range keys {
+		out = append(out, Public(&keys[i]))
+	}
+	httpx.OK(c, out)
+}
+
+// Create handles POST /api/v1/keys.
+func (h *Handler) Create(c *gin.Context) {
+	u := user.Current(c)
+	var in CreateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	rec, plain, err := h.svc.Create(u.ID, in)
+	if err != nil {
+		h.log.Warn("create key failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create key failed")
+		return
+	}
+	data := Public(rec)
+	data["key"] = plain // shown only once
+	httpx.Created(c, data)
+}
+
+// Update handles PATCH /api/v1/keys/:id.
+func (h *Handler) Update(c *gin.Context) {
+	u := user.Current(c)
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid key id")
+		return
+	}
+	var in UpdateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	rec, err := h.svc.Update(u.ID, id, in)
+	if err != nil {
+		if errors.Is(err, ErrKeyNotFound) {
+			httpx.Fail(c, http.StatusNotFound, "api key not found")
+			return
+		}
+		httpx.Fail(c, http.StatusInternalServerError, "update key failed")
+		return
+	}
+	httpx.OK(c, Public(rec))
+}
+
+// Delete handles DELETE /api/v1/keys/:id.
+func (h *Handler) Delete(c *gin.Context) {
+	u := user.Current(c)
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		httpx.Fail(c, http.StatusBadRequest, "invalid key id")
+		return
+	}
+	if err := h.svc.Delete(u.ID, id); err != nil {
+		if errors.Is(err, ErrKeyNotFound) {
+			httpx.Fail(c, http.StatusNotFound, "api key not found")
+			return
+		}
+		httpx.Fail(c, http.StatusInternalServerError, "revoke key failed")
+		return
+	}
+	httpx.OK(c, gin.H{"ok": true})
+}

server/internal/apikey/service.go

@@ -0,0 +1,160 @@
+package apikey
+
+import (
+	"encoding/json"
+	"errors"
+	"time"
+
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/crypto"
+	"openteam/server/internal/pkg/rand"
+	"openteam/server/internal/store"
+)
+
+var ErrKeyNotFound = errors.New("api key not found")
+
+type Service struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewService(db *gorm.DB, log *zap.Logger) *Service {
+	return &Service{db: db, log: log}
+}
+
+type CreateInput struct {
+	Name                string   `json:"name" binding:"required,max=128"`
+	QuotaTokensPerDay   *int64   `json:"quotaTokensPerDay"`
+	QuotaRequestsPerDay *int     `json:"quotaRequestsPerDay"`
+	AllowedModels       []string `json:"allowedModels"`
+	ExpiresInDays       *int     `json:"expiresInDays"`
+}
+
+type UpdateInput struct {
+	Name                *string  `json:"name"`
+	QuotaTokensPerDay   *int64   `json:"quotaTokensPerDay"`
+	QuotaRequestsPerDay *int     `json:"quotaRequestsPerDay"`
+	AllowedModels       []string `json:"allowedModels"`
+	ExpiresAt           *time.Time `json:"expiresAt"`
+	Status              *string  `json:"status"`
+}
+
+// Create generates a key and returns it once along with the stored record.
+func (s *Service) Create(userID int64, in CreateInput) (*store.ApiKey, string, error) {
+	plain, err := rand.Base62(48)
+	if err != nil {
+		return nil, "", err
+	}
+	full := "sk-" + plain
+	rec := &store.ApiKey{
+		UserID:              userID,
+		Name:                in.Name,
+		KeyHash:             crypto.HashSHA256(full),
+		KeyPrefix:           "sk-" + plain[:8],
+		QuotaTokensPerDay:   in.QuotaTokensPerDay,
+		QuotaRequestsPerDay: in.QuotaRequestsPerDay,
+		AllowedModels:       in.AllowedModels,
+		Status:              "active",
+	}
+	if in.ExpiresInDays != nil && *in.ExpiresInDays > 0 {
+		t := time.Now().AddDate(0, 0, *in.ExpiresInDays)
+		rec.ExpiresAt = &t
+	}
+	if err := s.db.Create(rec).Error; err != nil {
+		return nil, "", err
+	}
+	return rec, full, nil
+}
+
+// List returns the user's keys (never the hash).
+func (s *Service) List(userID int64) ([]store.ApiKey, error) {
+	var keys []store.ApiKey
+	err := s.db.Where("user_id = ?", userID).Order("id DESC").Find(&keys).Error
+	return keys, err
+}
+
+// Update patches a key owned by the user.
+func (s *Service) Update(userID, keyID int64, in UpdateInput) (*store.ApiKey, error) {
+	var k store.ApiKey
+	if err := s.db.First(&k, "id = ? AND user_id = ?", keyID, userID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrKeyNotFound
+		}
+		return nil, err
+	}
+	updates := map[string]any{}
+	if in.Name != nil {
+		updates["name"] = *in.Name
+	}
+	if in.QuotaTokensPerDay != nil {
+		updates["quota_tokens_per_day"] = *in.QuotaTokensPerDay
+	}
+	if in.QuotaRequestsPerDay != nil {
+		updates["quota_requests_per_day"] = *in.QuotaRequestsPerDay
+	}
+	if in.AllowedModels != nil {
+		// GORM map updates skip the json serializer, so encode explicitly.
+		modelsJSON, err := json.Marshal(in.AllowedModels)
+		if err != nil {
+			return nil, err
+		}
+		updates["allowed_models"] = string(modelsJSON)
+	}
+	if in.ExpiresAt != nil {
+		updates["expires_at"] = in.ExpiresAt
+	}
+	if in.Status != nil {
+		updates["status"] = *in.Status
+	}
+	if len(updates) > 0 {
+		if err := s.db.Model(&k).Updates(updates).Error; err != nil {
+			return nil, err
+		}
+	}
+	return s.Get(userID, keyID)
+}
+
+// Delete revokes a key (soft revoke by status).
+func (s *Service) Delete(userID, keyID int64) error {
+	res := s.db.Model(&store.ApiKey{}).
+		Where("id = ? AND user_id = ?", keyID, userID).
+		Update("status", "revoked")
+	if res.Error != nil {
+		return res.Error
+	}
+	if res.RowsAffected == 0 {
+		return ErrKeyNotFound
+	}
+	return nil
+}
+
+// Get loads one key owned by the user.
+func (s *Service) Get(userID, keyID int64) (*store.ApiKey, error) {
+	var k store.ApiKey
+	if err := s.db.First(&k, "id = ? AND user_id = ?", keyID, userID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrKeyNotFound
+		}
+		return nil, err
+	}
+	return &k, nil
+}
+
+// Public returns a DTO without the hash.
+func Public(k *store.ApiKey) map[string]any {
+	return map[string]any{
+		"id":                 k.ID,
+		"userId":             k.UserID,
+		"name":               k.Name,
+		"keyPrefix":          k.KeyPrefix,
+		"quotaTokensPerDay":  k.QuotaTokensPerDay,
+		"quotaRequestsPerDay": k.QuotaRequestsPerDay,
+		"allowedModels":      k.AllowedModels,
+		"expiresAt":          k.ExpiresAt,
+		"status":             k.Status,
+		"lastUsedAt":         k.LastUsedAt,
+		"createdAt":          k.CreatedAt,
+	}
+}

server/internal/billing/service.go

@@ -0,0 +1,117 @@
+package billing
+
+import (
+	"errors"
+	"time"
+
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+
+	"openteam/server/internal/store"
+)
+
+var (
+	ErrInsufficientBalance = errors.New("insufficient balance")
+	ErrUserNotFound        = errors.New("user not found")
+)
+
+// PriceSnapshot mirrors a model's prices at billing time.
+type PriceSnapshot struct {
+	InputPrice     decimal.Decimal
+	OutputPrice    decimal.Decimal
+	CacheReadPrice decimal.Decimal
+}
+
+// CostFromPrices computes cost for token counts using per-1M-token prices.
+func CostFromPrices(in, out, cacheRead int64, prices PriceSnapshot) decimal.Decimal {
+	perM := decimal.NewFromInt(1_000_000)
+	cost := prices.InputPrice.Mul(decimal.NewFromInt(in)).Div(perM).
+		Add(prices.OutputPrice.Mul(decimal.NewFromInt(out)).Div(perM)).
+		Add(prices.CacheReadPrice.Mul(decimal.NewFromInt(cacheRead)).Div(perM))
+	return cost.Round(8)
+}
+
+// EstimateCost approximates cost from token estimates.
+func (s *Service) EstimateCost(modelID int64, in, out, cacheRead int64) (decimal.Decimal, error) {
+	var m store.Model
+	if err := s.db.First(&m, modelID).Error; err != nil {
+		return decimal.Zero, err
+	}
+	return CostFromPrices(in, out, cacheRead, PriceSnapshot{
+		InputPrice: m.InputPrice, OutputPrice: m.OutputPrice, CacheReadPrice: m.CacheReadPrice,
+	}), nil
+}
+
+type Service struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewService(db *gorm.DB, log *zap.Logger) *Service {
+	return &Service{db: db, log: log}
+}
+
+// CheckBalance returns whether the user can afford the estimated cost.
+func (s *Service) CheckBalance(userID int64, estimated decimal.Decimal) error {
+	var u store.User
+	if err := s.db.First(&u, userID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrUserNotFound
+		}
+		return err
+	}
+	if u.Balance.LessThan(estimated) {
+		return ErrInsufficientBalance
+	}
+	return nil
+}
+
+// Deduct atomically debits the user balance and appends a ledger entry.
+func (s *Service) Deduct(userID int64, change decimal.Decimal, logType, refID string) (decimal.Decimal, error) {
+	return s.mutateBalance(userID, change.Neg(), logType, refID)
+}
+
+// Credit adds to the user balance (recharge / refund / admin adjust).
+func (s *Service) Credit(userID int64, change decimal.Decimal, logType, refID string) (decimal.Decimal, error) {
+	return s.mutateBalance(userID, change, logType, refID)
+}
+
+// mutateBalance performs the balance update in a transaction so ledger and
+// balance always agree.
+func (s *Service) mutateBalance(userID int64, delta decimal.Decimal, logType, refID string) (decimal.Decimal, error) {
+	var after decimal.Decimal
+	err := s.db.Transaction(func(tx *gorm.DB) error {
+		var u store.User
+		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&u, userID).Error; err != nil {
+			return err
+		}
+		newBal := u.Balance.Add(delta)
+		if newBal.LessThan(decimal.Zero) {
+			return ErrInsufficientBalance
+		}
+		if err := tx.Model(&u).Update("balance", newBal).Error; err != nil {
+			return err
+		}
+		after = newBal
+		return tx.Create(&store.BalanceLog{
+			UserID:       userID,
+			Change:       delta,
+			BalanceAfter: newBal,
+			Type:         logType,
+			RefID:        refID,
+			CreatedAt:    time.Now(),
+		}).Error
+	})
+	if err != nil {
+		return decimal.Zero, err
+	}
+	return after, nil
+}
+
+// AdminAdjust changes a user's balance with an optional reason.
+func (s *Service) AdminAdjust(userID int64, amount decimal.Decimal, reason string) (decimal.Decimal, error) {
+	return s.mutateBalance(userID, amount, "admin_adjust", reason)
+}
+

server/internal/channel/health.go

@@ -0,0 +1,53 @@
+package channel
+
+import (
+	"time"
+
+	"go.uber.org/zap"
+
+	"openteam/server/internal/store"
+)
+
+// StartHealthCheck runs the periodic health-check loop in a goroutine.
+// Only channels that are enabled and have a bound test model are checked.
+func (s *Service) StartHealthCheck() {
+	go func() {
+		ticker := time.NewTicker(s.cfg.HealthCheck.Interval)
+		defer ticker.Stop()
+		s.runHealthCheck()
+		for range ticker.C {
+			s.runHealthCheck()
+		}
+	}()
+}
+
+func (s *Service) runHealthCheck() {
+	var channels []store.Channel
+	if err := s.db.Where("enabled = ?", true).Find(&channels).Error; err != nil {
+		s.log.Warn("health check query failed", zap.Error(err))
+		return
+	}
+	for i := range channels {
+		ch := &channels[i]
+		// Skip channels already in cooldown until the cooldown elapses.
+		if ch.HealthStatus == "cooldown" {
+			continue
+		}
+		ok, _, _, err := s.Test(ch)
+		if err != nil || !ok {
+			s.MarkFailure(ch.ID)
+			continue
+		}
+		s.MarkHealthy(ch.ID, "healthy")
+	}
+}
+
+// RecoverCooldown moves channels back from cooldown to degraded after the
+// cooldown window, giving them another chance to pass the health check.
+// Called periodically; keeps cooldown bounded.
+func (s *Service) RecoverCooldown() {
+	cutoff := time.Now().Add(-s.cfg.HealthCheck.Cooldown)
+	s.db.Model(&store.Channel{}).
+		Where("health_status = ? AND updated_at < ?", "cooldown", cutoff).
+		Updates(map[string]any{"health_status": "degraded", "health_failures": 0})
+}

server/internal/channel/ops.go

@@ -0,0 +1,220 @@
+package channel
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/crypto"
+	"openteam/server/internal/store"
+)
+
+// EncryptKey encrypts an upstream API key for storage.
+func (s *Service) EncryptKey(plain string) (string, error) {
+	return crypto.Encrypt(plain, s.master)
+}
+
+// ImportModels fetches the channel's model list (GET /v1/models) and creates
+// global Model records plus bindings. Returns the imported model names.
+func (s *Service) ImportModels(ch *store.Channel) ([]string, error) {
+	key, err := s.DecryptKey(ch.APIKeyEnc)
+	if err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	base := strings.TrimSuffix(ch.BaseURL, "/")
+	url := base + "/v1/models"
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Authorization", "Bearer "+key)
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	raw, err := io.ReadAll(io.LimitReader(resp.Body, 4<<20))
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode >= 400 {
+		return nil, fmt.Errorf("channel returned %d: %s", resp.StatusCode, truncate(string(raw), 200))
+	}
+
+	var payload struct {
+		Data []struct {
+			ID string `json:"id"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(raw, &payload); err != nil {
+		return nil, err
+	}
+	if len(payload.Data) == 0 {
+		return nil, errors.New("no models returned")
+	}
+
+	imported := []string{}
+	err = s.db.Transaction(func(tx *gorm.DB) error {
+		for _, m := range payload.Data {
+			if m.ID == "" {
+				continue
+			}
+			var model store.Model
+			err := tx.Where("name = ?", m.ID).First(&model).Error
+			if errors.Is(err, gorm.ErrRecordNotFound) {
+				model = store.Model{Name: m.ID, DisplayName: m.ID}
+				if err := tx.Create(&model).Error; err != nil {
+					return err
+				}
+			} else if err != nil {
+				return err
+			}
+			var binding store.ChannelModelBinding
+			err = tx.Where("channel_id = ? AND model_id = ?", ch.ID, model.ID).First(&binding).Error
+			if errors.Is(err, gorm.ErrRecordNotFound) {
+				binding = store.ChannelModelBinding{
+					ChannelID: ch.ID, ModelID: model.ID, UpstreamModel: m.ID, Weight: 1,
+				}
+				if err := tx.Create(&binding).Error; err != nil {
+					return err
+				}
+			}
+			imported = append(imported, m.ID)
+		}
+		return nil
+	})
+	return imported, err
+}
+
+// Test sends a cheap test request to the channel and reports success + latency.
+func (s *Service) Test(ch *store.Channel) (bool, int, string, error) {
+	key, err := s.DecryptKey(ch.APIKeyEnc)
+	if err != nil {
+		return false, 0, "", err
+	}
+	model := s.cfg.HealthCheck.TestModel
+	if model == "" {
+		// Pick the first bound model, if any.
+		var b store.ChannelModelBinding
+		if err := s.db.Where("channel_id = ?", ch.ID).First(&b).Error; err == nil {
+			model = b.UpstreamModel
+		}
+	}
+	if model == "" {
+		return false, 0, "", errors.New("no test model configured; set HEALTHCHECK_TEST_MODEL or bind a model")
+	}
+
+	timeout := time.Duration(s.cfg.HealthCheck.TimeoutMs) * time.Millisecond
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	// Test the first endpoint the channel actually serves, so channels that
+	// omit chat completions (e.g. Anthropic-only) still get a valid probe.
+	testFmt := pickTestFormat(ch)
+	var body []byte
+	switch testFmt {
+	case store.FormatAnthropic:
+		body, _ = json.Marshal(map[string]any{
+			"model": model, "max_tokens": 8,
+			"messages": []any{map[string]any{"role": "user", "content": "ping"}},
+		})
+	case store.FormatOpenAIResponses:
+		body, _ = json.Marshal(map[string]any{"model": model, "input": "ping"})
+	default:
+		body, _ = json.Marshal(map[string]any{
+			"model": model,
+			"messages": []any{map[string]any{"role": "user", "content": "ping"}},
+			"max_tokens": 8,
+		})
+	}
+
+	url := strings.TrimSuffix(ch.BaseURL, "/") + healthCheckPath(testFmt)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, strings.NewReader(string(body)))
+	if err != nil {
+		return false, 0, "", err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+key)
+	if testFmt == store.FormatAnthropic {
+		req.Header.Set("anthropic-version", "2023-06-01")
+	}
+
+	start := time.Now()
+	resp, err := http.DefaultClient.Do(req)
+	latency := int(time.Since(start).Milliseconds())
+	if err != nil {
+		return false, latency, "", err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 400 {
+		raw, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
+		return false, latency, "", fmt.Errorf("test request failed: %d %s", resp.StatusCode, truncate(string(raw), 160))
+	}
+	return true, latency, model, nil
+}
+
+// MarkHealthy updates health status and resets the failure counter.
+func (s *Service) MarkHealthy(chID int64, status string) {
+	s.db.Model(&store.Channel{}).Where("id = ?", chID).
+		Updates(map[string]any{"health_status": status, "health_failures": 0})
+}
+
+// MarkFailure increments the failure counter and sets cooldown when maxed.
+func (s *Service) MarkFailure(chID int64) {
+	var ch store.Channel
+	if err := s.db.First(&ch, chID).Error; err != nil {
+		return
+	}
+	failures := ch.HealthFailures + 1
+	status := "degraded"
+	if failures >= s.cfg.HealthCheck.MaxFailures {
+		status = "cooldown"
+	}
+	s.db.Model(&ch).Updates(map[string]any{"health_failures": failures, "health_status": status})
+	s.log.Info("channel health failure", zap.Int64("channel_id", chID),
+		zap.Int("failures", failures), zap.String("status", status))
+}
+
+// pickTestFormat chooses a supported format to probe, preferring the cheapest
+// endpoint. Falls back to chat completions so legacy channels keep working.
+func pickTestFormat(ch *store.Channel) string {
+	for _, want := range []string{store.FormatOpenAIChat, store.FormatAnthropic, store.FormatOpenAIResponses} {
+		for _, f := range ch.FormatsResolved() {
+			if f == want {
+				return want
+			}
+		}
+	}
+	return store.FormatOpenAIChat
+}
+
+func healthCheckPath(f string) string {
+	switch f {
+	case store.FormatAnthropic:
+		return "/v1/messages"
+	case store.FormatOpenAIResponses:
+		return "/v1/responses"
+	default:
+		return "/v1/chat/completions"
+	}
+}
+
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n] + "..."
+}

server/internal/channel/service.go

@@ -0,0 +1,156 @@
+package channel
+
+import (
+	"errors"
+	"math/rand"
+	"sort"
+	"sync"
+
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/config"
+	"openteam/server/internal/pkg/crypto"
+	"openteam/server/internal/store"
+)
+
+var ErrNoChannel = errors.New("no available channel for model")
+
+// Service manages channels, model bindings and load-balanced selection.
+type Service struct {
+	db  *gorm.DB
+	cfg *config.Config
+	log *zap.Logger
+
+	mu     sync.RWMutex
+	sem    map[int64]chan struct{} // per-channel concurrency limiter
+	master string
+}
+
+func NewService(db *gorm.DB, cfg *config.Config, log *zap.Logger) *Service {
+	return &Service{
+		db: db, cfg: cfg, log: log,
+		sem:    map[int64]chan struct{}{},
+		master: cfg.MasterKey,
+	}
+}
+
+// DecryptKey decrypts a channel's stored upstream API key.
+func (s *Service) DecryptKey(enc string) (string, error) {
+	return crypto.Decrypt(enc, s.master)
+}
+
+// Acquire takes a concurrency slot for a channel (blocks if saturated).
+func (s *Service) Acquire(channelID int64) (func(), error) {
+	s.mu.Lock()
+	lim, ok := s.sem[channelID]
+	if !ok {
+		var rec store.Channel
+		if err := s.db.First(&rec, channelID).Error; err != nil {
+			s.mu.Unlock()
+			return nil, err
+		}
+		limit := rec.MaxConcurrency
+		if limit <= 0 {
+			limit = 100
+		}
+		lim = make(chan struct{}, limit)
+		s.sem[channelID] = lim
+	}
+	s.mu.Unlock()
+	lim <- struct{}{}
+	return func() { <-lim }, nil
+}
+
+// ResolveModel returns the model registry record.
+func (s *Service) ResolveModel(name string) (*store.Model, error) {
+	var m store.Model
+	if err := s.db.Where("name = ? AND enabled = ?", name, true).First(&m).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, errors.New("model not found: " + name)
+		}
+		return nil, err
+	}
+	return &m, nil
+}
+
+// SelectChannel picks a healthy channel bound to the given model.
+// Channels with higher priority (lower number) and higher weight win;
+// cooldown channels are skipped, degraded channels are deprioritized.
+// Channels in exclude (already tried in this request) are skipped.
+func (s *Service) SelectChannel(modelID int64, exclude map[int64]bool) (*store.Channel, *store.ChannelModelBinding, error) {
+	var bindings []store.ChannelModelBinding
+	if err := s.db.Preload("Channel").Where("model_id = ?", modelID).Find(&bindings).Error; err != nil {
+		return nil, nil, err
+	}
+	var candidates []struct {
+		ch *store.Channel
+		b  *store.ChannelModelBinding
+		score float64
+	}
+	for i := range bindings {
+		ch := &bindings[i].Channel
+		if !ch.Enabled {
+			continue
+		}
+		if ch.HealthStatus == "cooldown" {
+			continue
+		}
+		if exclude[ch.ID] {
+			continue
+		}
+		score := float64(bindings[i].Weight)
+		if ch.HealthStatus == "degraded" {
+			score *= 0.1
+		}
+		candidates = append(candidates, struct {
+			ch *store.Channel
+			b  *store.ChannelModelBinding
+			score float64
+		}{ch: ch, b: &bindings[i], score: score})
+	}
+	if len(candidates) == 0 {
+		return nil, nil, ErrNoChannel
+	}
+	// Sort by priority asc, then weight desc.
+	sort.SliceStable(candidates, func(i, j int) bool {
+		if candidates[i].ch.Priority != candidates[j].ch.Priority {
+			return candidates[i].ch.Priority < candidates[j].ch.Priority
+		}
+		return candidates[i].score > candidates[j].score
+	})
+	// Weighted random pick among the top priority group.
+	total := 0.0
+	for _, c := range candidates {
+		total += c.score
+	}
+	if total <= 0 {
+		return candidates[0].ch, candidates[0].b, nil
+	}
+	pick := rand.Float64() * total
+	for _, c := range candidates {
+		pick -= c.score
+		if pick <= 0 {
+			return c.ch, c.b, nil
+		}
+	}
+	return candidates[0].ch, candidates[0].b, nil
+}
+
+// ListModelsForChannel returns the model names a channel serves.
+func (s *Service) ListModelsForChannel(channelID int64) ([]string, error) {
+	var names []string
+	err := s.db.Table("channel_model_bindings").
+		Joins("JOIN models ON models.id = channel_model_bindings.model_id").
+		Where("channel_model_bindings.channel_id = ? AND models.enabled = ?", channelID, true).
+		Order("models.sort ASC, models.id ASC").
+		Pluck("models.name", &names).Error
+	return names, err
+}
+
+// ListEnabledModels returns all enabled models for GET /v1/models.
+func (s *Service) ListEnabledModels() ([]store.Model, error) {
+	var models []store.Model
+	err := s.db.Where("enabled = ?", true).Order("sort ASC, id ASC").Find(&models).Error
+	return models, err
+}

server/internal/config/config.go

@@ -0,0 +1,143 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+)
+
+// Config is the runtime configuration, loaded from environment variables.
+type Config struct {
+	Env   string
+	Debug bool
+
+	HTTPPort    string
+	PublicBase  string // external base URL, used for cookies
+	AllowOrigins []string
+
+	DB struct {
+		Driver string // "sqlite" (dev default) or "postgres"
+		DSN    string
+	}
+
+	Redis struct {
+		Addr     string
+		Password string
+		Enabled  bool
+	}
+
+	Auth struct {
+		AccessTokenTTL       time.Duration
+		RefreshTokenTTL      time.Duration
+		JWTSecret            string
+		RefreshCookieName    string
+		RefreshCookieSecure  bool // false for local http dev; set true behind TLS
+		RefreshCookieSameSite string
+	}
+
+	// MasterKey encrypts channel API keys at rest (AES-GCM).
+	MasterKey string
+
+	Proxy struct {
+		DefaultMaxTokens    int
+		DefaultTimeoutMs    int
+		BillingExactBalance bool // reject when estimated cost > balance
+		MaxRetries          int  // additional channel attempts on transport/5xx failures
+	}
+
+	Registration struct {
+		Mode string // "open" | "invite"
+	}
+
+	HealthCheck struct {
+		Interval      time.Duration
+		MaxFailures   int
+		Cooldown      time.Duration
+		TimeoutMs     int
+		TestModel     string
+	}
+
+	RateLimit struct {
+		RequestsPerMin int // per user global limiter
+		Burst          int
+	}
+
+	MetricsEnabled bool
+}
+
+func Load() *Config {
+	c := &Config{}
+	c.Env = get("APP_ENV", "development")
+	c.Debug = strings.EqualFold(get("DEBUG", "false"), "true")
+	c.HTTPPort = get("HTTP_PORT", "8080")
+	c.PublicBase = get("PUBLIC_BASE", "http://localhost:8080")
+	if o := get("CORS_ORIGINS", "*"); o != "*" {
+		c.AllowOrigins = strings.Split(o, ",")
+	} else {
+		c.AllowOrigins = []string{"*"}
+	}
+
+	c.DB.Driver = get("DB_DRIVER", "sqlite")
+	if c.DB.Driver == "postgres" {
+		c.DB.DSN = get("DATABASE_URL", "host=localhost user=postgres password=postgres dbname=openteam port=5432 sslmode=disable")
+	} else {
+		path := get("SQLITE_PATH", "data/openteam.db")
+		c.DB.DSN = path
+	}
+
+	c.Redis.Addr = get("REDIS_ADDR", "localhost:6379")
+	c.Redis.Password = get("REDIS_PASSWORD", "")
+	c.Redis.Enabled = strings.EqualFold(get("REDIS_ENABLED", "false"), "true")
+
+	c.Auth.AccessTokenTTL = duration(get("ACCESS_TOKEN_TTL", "2h"), 2*time.Hour)
+	c.Auth.RefreshTokenTTL = duration(get("REFRESH_TOKEN_TTL", "168h"), 7*24*time.Hour)
+	c.Auth.JWTSecret = get("JWT_SECRET", "dev-only-secret-change-me")
+	c.Auth.RefreshCookieName = get("REFRESH_COOKIE_NAME", "ot_refresh")
+	c.Auth.RefreshCookieSecure = strings.EqualFold(get("REFRESH_COOKIE_SECURE", "false"), "true")
+	c.Auth.RefreshCookieSameSite = get("REFRESH_COOKIE_SAMESITE", "lax")
+
+	c.MasterKey = get("MASTER_KEY", "dev-only-master-key-change-me")
+
+	c.Proxy.DefaultMaxTokens = intVal(get("DEFAULT_MAX_TOKENS", "4096"), 4096)
+	c.Proxy.DefaultTimeoutMs = intVal(get("PROXY_TIMEOUT_MS", "300000"), 300000)
+	c.Proxy.BillingExactBalance = strings.EqualFold(get("BILLING_EXACT_BALANCE", "false"), "true")
+	c.Proxy.MaxRetries = intVal(get("PROXY_MAX_RETRIES", "1"), 1)
+
+	c.Registration.Mode = get("REGISTRATION_MODE", "open")
+
+	c.HealthCheck.Interval = duration(get("HEALTHCHECK_INTERVAL", "60s"), time.Minute)
+	c.HealthCheck.MaxFailures = intVal(get("HEALTHCHECK_MAX_FAILURES", "3"), 3)
+	c.HealthCheck.Cooldown = duration(get("HEALTHCHECK_COOLDOWN", "300s"), 5*time.Minute)
+	c.HealthCheck.TimeoutMs = intVal(get("HEALTHCHECK_TIMEOUT_MS", "15000"), 15000)
+	c.HealthCheck.TestModel = get("HEALTHCHECK_TEST_MODEL", "")
+
+	c.RateLimit.RequestsPerMin = intVal(get("RATE_LIMIT_PER_MIN", "60"), 60)
+	c.RateLimit.Burst = intVal(get("RATE_LIMIT_BURST", "120"), 120)
+
+	c.MetricsEnabled = strings.EqualFold(get("METRICS_ENABLED", "false"), "true")
+	return c
+}
+
+func get(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}
+
+func intVal(s string, def int) int {
+	n := 0
+	if _, err := fmt.Sscanf(s, "%d", &n); err != nil || n <= 0 {
+		return def
+	}
+	return n
+}
+
+func duration(s string, def time.Duration) time.Duration {
+	d, err := time.ParseDuration(s)
+	if err != nil || d <= 0 {
+		return def
+	}
+	return d
+}

server/internal/pkg/crypto/crypto.go

@@ -0,0 +1,64 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// Encrypt seals a secret with AES-GCM. The master key can be any string;
+// it is hashed to a fixed-size AES key.
+func Encrypt(plaintext, masterKey string) (string, error) {
+	key := sha256.Sum256([]byte(masterKey))
+	block, err := aes.NewCipher(key[:])
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+	sealed := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return base64.StdEncoding.EncodeToString(sealed), nil
+}
+
+// Decrypt opens a ciphertext produced by Encrypt.
+func Decrypt(ciphertext, masterKey string) (string, error) {
+	key := sha256.Sum256([]byte(masterKey))
+	data, err := base64.StdEncoding.DecodeString(ciphertext)
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(key[:])
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	if len(data) < gcm.NonceSize() {
+		return "", errors.New("ciphertext too short")
+	}
+	nonce, sealed := data[:gcm.NonceSize()], data[gcm.NonceSize():]
+	plain, err := gcm.Open(nil, nonce, sealed, nil)
+	if err != nil {
+		return "", fmt.Errorf("decrypt failed (bad master key?): %w", err)
+	}
+	return string(plain), nil
+}
+
+// HashSHA256 returns the hex SHA-256 of a string (used for API key lookup).
+func HashSHA256(s string) string {
+	sum := sha256.Sum256([]byte(s))
+	return fmt.Sprintf("%x", sum)
+}

server/internal/pkg/httpx/httpx.go

@@ -0,0 +1,42 @@
+package httpx
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+// APIError is the standard error body for the management API.
+type APIError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+// OK writes a JSON success response.
+func OK(c *gin.Context, data any) {
+	c.JSON(http.StatusOK, gin.H{"code": 0, "data": data})
+}
+
+// Created writes a 201 response.
+func Created(c *gin.Context, data any) {
+	c.JSON(http.StatusCreated, gin.H{"code": 0, "data": data})
+}
+
+// Fail writes an error response with the given status.
+func Fail(c *gin.Context, status int, message string) {
+	c.AbortWithStatusJSON(status, gin.H{"code": status, "message": message})
+}
+
+// FailWithCode writes an error with a custom business code.
+func FailWithCode(c *gin.Context, status, code int, message string) {
+	c.AbortWithStatusJSON(status, gin.H{"code": code, "message": message})
+}
+
+// Bind parses the JSON body and aborts with 400 on failure.
+func Bind(c *gin.Context, dst any) bool {
+	if err := c.ShouldBindJSON(dst); err != nil {
+		Fail(c, http.StatusBadRequest, "invalid request body: "+err.Error())
+		return false
+	}
+	return true
+}

server/internal/pkg/jwt/jwt.go

@@ -0,0 +1,66 @@
+package jwt
+
+import (
+	"errors"
+	"strconv"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+// Claims is the payload of a signed token.
+type Claims struct {
+	UserID   int64  `json:"uid"`
+	Username string `json:"username"`
+	Role     string `json:"role"`
+	Type     string `json:"typ"` // access | refresh
+	jwt.RegisteredClaims
+}
+
+func sign(secret string, c Claims) (string, error) {
+	t := jwt.NewWithClaims(jwt.SigningMethodHS256, c)
+	return t.SignedString([]byte(secret))
+}
+
+// SignAccess issues a short-lived access token.
+func SignAccess(secret string, userID int64, username, role string, ttl time.Duration) (string, error) {
+	return sign(secret, Claims{
+		UserID: userID, Username: username, Role: role, Type: "access",
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(ttl)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+			Subject:   fmtID(userID),
+		},
+	})
+}
+
+// SignRefresh issues a long-lived refresh token.
+func SignRefresh(secret string, userID int64, ttl time.Duration) (string, error) {
+	return sign(secret, Claims{
+		UserID: userID, Type: "refresh",
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(ttl)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+			Subject:   fmtID(userID),
+		},
+	})
+}
+
+// Parse validates a token and returns its claims.
+func Parse(secret, token string) (*Claims, error) {
+	var c Claims
+	parsed, err := jwt.ParseWithClaims(token, &c, func(t *jwt.Token) (interface{}, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, errors.New("unexpected signing method")
+		}
+		return []byte(secret), nil
+	})
+	if err != nil || !parsed.Valid {
+		return nil, errors.New("invalid token")
+	}
+	return &c, nil
+}
+
+func fmtID(id int64) string {
+	return strconv.FormatInt(id, 10)
+}

server/internal/pkg/password/password.go

@@ -0,0 +1,62 @@
+package password
+
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"strings"
+
+	"golang.org/x/crypto/argon2"
+)
+
+const (
+	argonTime    = 3
+	argonMemory  = 64 * 1024
+	argonThreads = 2
+	argonKeyLen  = 32
+	argonSaltLen = 16
+)
+
+// Hash hashes a plaintext password with argon2id.
+func Hash(plain string) (string, error) {
+	salt := make([]byte, argonSaltLen)
+	if _, err := rand.Read(salt); err != nil {
+		return "", err
+	}
+	key := argon2.IDKey([]byte(plain), salt, argonTime, argonMemory, argonThreads, argonKeyLen)
+	enc := base64.RawStdEncoding
+	return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
+		argon2.Version, argonMemory, argonTime, argonThreads,
+		enc.EncodeToString(salt), enc.EncodeToString(key)), nil
+}
+
+// Verify checks a plaintext password against an argon2id hash string.
+func Verify(plain, encoded string) (bool, error) {
+	parts := strings.Split(encoded, "$")
+	if len(parts) != 6 || parts[1] != "argon2id" {
+		return false, errors.New("malformed password hash")
+	}
+	var version int
+	var memory uint32
+	var time_ uint32
+	var threads uint8
+	if _, err := fmt.Sscanf(parts[2], "v=%d", &version); err != nil {
+		return false, err
+	}
+	if _, err := fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &time_, &threads); err != nil {
+		return false, err
+	}
+	enc := base64.RawStdEncoding
+	salt, err := enc.DecodeString(parts[4])
+	if err != nil {
+		return false, err
+	}
+	want, err := enc.DecodeString(parts[5])
+	if err != nil {
+		return false, err
+	}
+	got := argon2.IDKey([]byte(plain), salt, time_, memory, threads, uint32(len(want)))
+	return subtle.ConstantTimeCompare(got, want) == 1, nil
+}

server/internal/pkg/rand/rand.go

@@ -0,0 +1,21 @@
+package rand
+
+import (
+	crand "crypto/rand"
+	"math/big"
+)
+
+const base62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+// Base62 returns a cryptographically random base62 string of length n.
+func Base62(n int) (string, error) {
+	out := make([]byte, n)
+	for i := range out {
+		idx, err := crand.Int(crand.Reader, big.NewInt(int64(len(base62))))
+		if err != nil {
+			return "", err
+		}
+		out[i] = base62[idx.Int64()]
+	}
+	return string(out), nil
+}

server/internal/pkg/ratelimit/ratelimit.go

@@ -0,0 +1,73 @@
+package ratelimit
+
+import (
+	"sync"
+	"time"
+)
+
+// Limiter is a token-bucket rate limiter keyed by string.
+type Limiter struct {
+	mu    sync.Mutex
+	rate  float64 // tokens per second
+	burst float64
+	tokens map[string]*bucket
+}
+
+type bucket struct {
+	tokens   float64
+	lastFill time.Time
+}
+
+// New creates a limiter refilling `rate` tokens/sec with `burst` capacity.
+func New(rate float64, burst int) *Limiter {
+	return &Limiter{
+		rate:   rate,
+		burst:  float64(burst),
+		tokens: map[string]*bucket{},
+	}
+}
+
+// Allow checks whether `key` may take one token now.
+func (l *Limiter) Allow(key string) bool {
+	return l.Take(key, 1)
+}
+
+// Take checks whether `key` may take n tokens now.
+func (l *Limiter) Take(key string, n float64) bool {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	now := time.Now()
+	b, ok := l.tokens[key]
+	if !ok {
+		b = &bucket{tokens: l.burst, lastFill: now}
+		l.tokens[key] = b
+	}
+	// Refill based on elapsed time.
+	elapsed := now.Sub(b.lastFill).Seconds()
+	b.tokens = minF(l.burst, b.tokens+elapsed*l.rate)
+	b.lastFill = now
+	if b.tokens >= n {
+		b.tokens -= n
+		return true
+	}
+	return false
+}
+
+// Sweep removes idle buckets to bound memory. Call periodically.
+func (l *Limiter) Sweep(olderThan time.Duration) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	cutoff := time.Now().Add(-olderThan)
+	for k, b := range l.tokens {
+		if b.lastFill.Before(cutoff) {
+			delete(l.tokens, k)
+		}
+	}
+}
+
+func minF(a, b float64) float64 {
+	if a < b {
+		return a
+	}
+	return b
+}

server/internal/proxy/claude/types.go

@@ -0,0 +1,50 @@
+package claude
+
+import "encoding/json"
+
+// Request is an Anthropic Messages request.
+type Request struct {
+	Model         string          `json:"model"`
+	MaxTokens     int             `json:"max_tokens"`
+	Stream        bool            `json:"stream"`
+	System        json.RawMessage `json:"system"`
+	Messages      json.RawMessage `json:"messages"`
+	Temperature   *float64        `json:"temperature"`
+	TopP          *float64        `json:"top_p"`
+	TopK          *int            `json:"top_k"`
+	StopSequences json.RawMessage `json:"stop_sequences"`
+	Tools         json.RawMessage `json:"tools"`
+	ToolChoice    json.RawMessage `json:"tool_choice"`
+	Metadata      json.RawMessage `json:"metadata"`
+}
+
+// Usage is the Claude usage block.
+type Usage struct {
+	InputTokens              int64 `json:"input_tokens"`
+	OutputTokens             int64 `json:"output_tokens"`
+	CacheReadInputTokens     int64 `json:"cache_read_input_tokens,omitempty"`
+	CacheCreationInputTokens int64 `json:"cache_creation_input_tokens,omitempty"`
+}
+
+// MessageResponse is the non-stream response.
+type MessageResponse struct {
+	ID         string          `json:"id"`
+	Type       string          `json:"type"`
+	Role       string          `json:"role"`
+	Model      string          `json:"model"`
+	Content    json.RawMessage `json:"content"`
+	StopReason string          `json:"stop_reason"`
+	StopSequence string        `json:"stop_sequence"`
+	Usage      *Usage          `json:"usage"`
+}
+
+// StreamEvent is one event in the Claude streaming event sequence.
+type StreamEvent struct {
+	Type      string          `json:"type"`
+	Message   json.RawMessage `json:"message,omitempty"`
+	Index     *int            `json:"index,omitempty"`
+	Delta     json.RawMessage `json:"delta,omitempty"`
+	Usage     json.RawMessage `json:"usage,omitempty"`
+	ContentBlock json.RawMessage `json:"content_block,omitempty"`
+	Error     json.RawMessage `json:"error,omitempty"`
+}

server/internal/proxy/convert/canonical.go

@@ -0,0 +1,196 @@
+package convert
+
+import (
+	"encoding/json"
+	"strings"
+
+	"openteam/server/internal/proxy/claude"
+	"openteam/server/internal/proxy/openai"
+	"openteam/server/internal/proxy/responses"
+)
+
+// CanonicalRequest is the gateway-internal standard form (OpenAI chat shape).
+// Every protocol is converted into this before being emitted to a channel.
+type CanonicalRequest struct {
+	Model          string
+	System         string
+	Messages       []openai.ChatMessage
+	Stream         bool
+	Temperature    *float64
+	TopP           *float64
+	MaxTokens      *int
+	Stop           []string
+	Tools          []openai.Tool
+	ToolChoice     json.RawMessage
+	ResponseFormat json.RawMessage
+	// Extra passthrough-only fields for OpenAI channels.
+	RawOpenAIExtras map[string]json.RawMessage
+}
+
+// contentString returns a plain-text representation of a message content,
+// handling both string and structured (Claude-style blocks) content.
+func contentString(raw json.RawMessage) string {
+	if len(raw) == 0 {
+		return ""
+	}
+	var s string
+	if err := json.Unmarshal(raw, &s); err == nil {
+		return s
+	}
+	var blocks []struct {
+		Type string `json:"type"`
+		Text string `json:"text"`
+	}
+	if err := json.Unmarshal(raw, &blocks); err == nil {
+		out := ""
+		for _, b := range blocks {
+			if b.Text != "" {
+				out += b.Text
+			}
+		}
+		return out
+	}
+	return ""
+}
+
+// requestFromOpenAIChat parses an OpenAI chat body into the canonical form.
+func requestFromOpenAIChat(body []byte) (*CanonicalRequest, error) {
+	var r openai.ChatRequest
+	if err := json.Unmarshal(body, &r); err != nil {
+		return nil, err
+	}
+	var msgs []openai.ChatMessage
+	if err := json.Unmarshal(r.Messages, &msgs); err != nil {
+		return nil, err
+	}
+	req := &CanonicalRequest{
+		Model:       r.Model,
+		Messages:    msgs,
+		Stream:      r.Stream,
+		Temperature: r.Temperature,
+		TopP:        r.TopP,
+		Stop:        parseStop(r.Stop),
+		ToolChoice:  r.ToolChoice,
+	}
+	if r.MaxTokens != nil {
+		req.MaxTokens = r.MaxTokens
+	} else if r.MaxCompl != nil {
+		req.MaxTokens = r.MaxCompl
+	}
+	if len(r.Tools) > 0 {
+		_ = json.Unmarshal(r.Tools, &req.Tools)
+	}
+	req.ResponseFormat = r.ResponseFmt
+	req.System = extractSystem(msgs)
+	req.RawOpenAIExtras = rawExtras(body, "model", "messages", "stream", "temperature", "top_p", "max_tokens", "max_completion_tokens", "stop", "tools", "tool_choice", "response_format", "user")
+	return req, nil
+}
+
+func requestFromClaude(body []byte) (*CanonicalRequest, error) {
+	var r claude.Request
+	if err := json.Unmarshal(body, &r); err != nil {
+		return nil, err
+	}
+	var msgs []openai.ChatMessage
+	// Claude messages: content can be a string or blocks; tool_use/tool_result
+	// blocks map to assistant.tool_calls and role=tool messages.
+	if err := claudeMessagesToChat(r.Messages, &msgs); err != nil {
+		return nil, err
+	}
+	req := &CanonicalRequest{
+		Model:       r.Model,
+		Messages:    msgs,
+		Stream:      r.Stream,
+		Temperature: r.Temperature,
+		TopP:        r.TopP,
+		Stop:        parseStop(r.StopSequences),
+	}
+	if r.MaxTokens > 0 {
+		mt := r.MaxTokens
+		req.MaxTokens = &mt
+	}
+	if len(r.Tools) > 0 {
+		_ = json.Unmarshal(r.Tools, &req.Tools)
+	}
+	req.ToolChoice = r.ToolChoice
+	// Claude system can be a string or array of blocks.
+	req.System = contentString(r.System)
+	return req, nil
+}
+
+func requestFromResponses(body []byte) (*CanonicalRequest, error) {
+	var r responses.Request
+	if err := json.Unmarshal(body, &r); err != nil {
+		return nil, err
+	}
+	req := &CanonicalRequest{
+		Model:  r.Model,
+		Stream: r.Stream,
+	}
+	// instructions → system.
+	req.System = contentString(r.Instructions)
+	// Parse input items into chat messages.
+	msgs, err := responsesInputToChat(r.Input)
+	if err != nil {
+		return nil, err
+	}
+	req.Messages = msgs
+	if r.MaxOutputTokens != nil {
+		req.MaxTokens = r.MaxOutputTokens
+	}
+	if len(r.Tools) > 0 {
+		_ = json.Unmarshal(r.Tools, &req.Tools)
+	}
+	// output_format / text.format → response_format.
+	if len(r.OutputFormat) > 0 {
+		req.ResponseFormat = r.OutputFormat
+	} else if len(r.Text) > 0 {
+		var t struct {
+			Format json.RawMessage `json:"format"`
+		}
+		if json.Unmarshal(r.Text, &t) == nil && len(t.Format) > 0 {
+			req.ResponseFormat = t.Format
+		}
+	}
+	return req, nil
+}
+
+func extractSystem(msgs []openai.ChatMessage) string {
+	var parts []string
+	for _, m := range msgs {
+		if m.Role == "system" {
+			if s := contentString(m.Content); s != "" {
+				parts = append(parts, s)
+			}
+		}
+	}
+	return strings.Join(parts, "\n")
+}
+
+func parseStop(raw json.RawMessage) []string {
+	if len(raw) == 0 {
+		return nil
+	}
+	var one string
+	if err := json.Unmarshal(raw, &one); err == nil {
+		return []string{one}
+	}
+	var many []string
+	if err := json.Unmarshal(raw, &many); err == nil {
+		return many
+	}
+	return nil
+}
+
+// rawExtras captures fields not otherwise modeled so they can be re-emitted
+// on OpenAI passthrough-style conversions.
+func rawExtras(body []byte, skip ...string) map[string]json.RawMessage {
+	var obj map[string]json.RawMessage
+	if json.Unmarshal(body, &obj) != nil {
+		return nil
+	}
+	for _, k := range skip {
+		delete(obj, k)
+	}
+	return obj
+}

server/internal/proxy/convert/chat_claude.go

@@ -0,0 +1,269 @@
+package convert
+
+import (
+	"encoding/json"
+
+	"openteam/server/internal/proxy/openai"
+)
+
+// claudeMessagesToChat converts Claude messages JSON into OpenAI chat messages.
+func claudeMessagesToChat(raw json.RawMessage, out *[]openai.ChatMessage) error {
+	var msgs []struct {
+		Role    string          `json:"role"`
+		Content json.RawMessage `json:"content"`
+	}
+	if err := json.Unmarshal(raw, &msgs); err != nil {
+		return err
+	}
+	for _, m := range msgs {
+		var text string
+		if err := json.Unmarshal(m.Content, &text); err == nil {
+			content, _ := json.Marshal(text)
+			*out = append(*out, openai.ChatMessage{Role: m.Role, Content: content})
+			continue
+		}
+		var blocks []map[string]json.RawMessage
+		if err := json.Unmarshal(m.Content, &blocks); err != nil {
+			return err
+		}
+		// Split blocks into: plain content parts, tool_use (→ tool_calls),
+		// and tool_result (→ separate role=tool messages).
+		var parts []json.RawMessage
+		var toolCalls []json.RawMessage
+		for _, b := range blocks {
+			var typ string
+			_ = json.Unmarshal(b["type"], &typ)
+			switch typ {
+			case "tool_use":
+				tc := map[string]any{
+					"id":   rawString(b["id"]),
+					"type": "function",
+					"function": map[string]any{
+						"name":      rawString(b["name"]),
+						"arguments": string(b["input"]),
+					},
+				}
+				encoded, _ := json.Marshal(tc)
+				toolCalls = append(toolCalls, encoded)
+			case "tool_result":
+				msg := openai.ChatMessage{
+					Role:       "tool",
+					ToolCallID: rawString(b["tool_use_id"]),
+				}
+				// content may be a string or array of text blocks.
+				if b["content"] != nil {
+					var s string
+					if json.Unmarshal(b["content"], &s) == nil {
+						content, _ := json.Marshal(s)
+						msg.Content = content
+					} else {
+						var texts []struct {
+							Type string `json:"type"`
+							Text string `json:"text"`
+						}
+						if json.Unmarshal(b["content"], &texts) == nil {
+							var buf string
+							for _, t := range texts {
+								buf += t.Text
+							}
+							content, _ := json.Marshal(buf)
+							msg.Content = content
+						}
+					}
+				}
+				encoded, _ := json.Marshal(msg)
+				*out = append(*out, msg)
+				_ = encoded
+			default:
+				// text / image blocks → OpenAI content part.
+				part, err := claudeBlockToOpenAIContent(b)
+				if err != nil {
+					return err
+				}
+				if part != nil {
+					parts = append(parts, part)
+				}
+			}
+		}
+		if len(toolCalls) > 0 {
+			msg := openai.ChatMessage{Role: "assistant"}
+			if len(parts) > 0 {
+				content, _ := json.Marshal(partsToText(parts))
+				msg.Content = content
+			}
+			tcArr, _ := json.Marshal(toolCalls)
+			msg.ToolCalls = tcArr
+			*out = append(*out, msg)
+		} else if len(parts) > 0 {
+			if len(parts) == 1 {
+				// Collapse a single text part back to a plain string.
+				var s string
+				if json.Unmarshal(parts[0], &s) == nil {
+					*out = append(*out, openai.ChatMessage{Role: m.Role, Content: parts[0]})
+				} else {
+					arr, _ := json.Marshal(parts)
+					*out = append(*out, openai.ChatMessage{Role: m.Role, Content: arr})
+				}
+			} else {
+				arr, _ := json.Marshal(parts)
+				*out = append(*out, openai.ChatMessage{Role: m.Role, Content: arr})
+			}
+		}
+	}
+	return nil
+}
+
+func claudeBlockToOpenAIContent(b map[string]json.RawMessage) (json.RawMessage, error) {
+	var typ string
+	_ = json.Unmarshal(b["type"], &typ)
+	switch typ {
+	case "text":
+		part := map[string]any{"type": "text", "text": rawString(b["text"])}
+		return json.Marshal(part)
+	case "image":
+		// b["source"] may not be present; be defensive.
+		if b["source"] != nil {
+			var src struct {
+				Type   string `json:"type"`
+				URL    string `json:"url"`
+				Data   string `json:"data"`
+				MediaType string `json:"media_type"`
+			}
+			_ = json.Unmarshal(b["source"], &src)
+			if src.URL != "" {
+				return json.Marshal(map[string]any{"type": "image_url", "image_url": map[string]any{"url": src.URL}})
+			}
+			if src.Data != "" {
+				return json.Marshal(map[string]any{"type": "image_url", "image_url": map[string]any{"url": "data:" + src.MediaType + ";base64," + src.Data}})
+			}
+		}
+		return nil, nil
+	default:
+		return nil, nil
+	}
+}
+
+func partsToText(parts []json.RawMessage) string {
+	var out string
+	for _, p := range parts {
+		var t struct {
+			Type string `json:"type"`
+			Text string `json:"text"`
+		}
+		if json.Unmarshal(p, &t) == nil {
+			out += t.Text
+		}
+	}
+	return out
+}
+
+func rawString(raw json.RawMessage) string {
+	if len(raw) == 0 {
+		return ""
+	}
+	var s string
+	if err := json.Unmarshal(raw, &s); err != nil {
+		return string(raw)
+	}
+	return s
+}
+
+// chatToClaudeMessages converts chat messages (with system already removed)
+// into Claude Messages body.
+func chatToClaudeMessages(msgs []openai.ChatMessage, system string) (map[string]any, error) {
+	claudeMsgs := []map[string]any{}
+	for _, m := range msgs {
+		if m.Role == "system" {
+			continue
+		}
+		// Tool calls on assistant messages → tool_use blocks.
+		if m.Role == "assistant" && len(m.ToolCalls) > 0 {
+			content := []map[string]any{}
+			// Preserve any text content.
+			if text := contentString(m.Content); text != "" {
+				content = append(content, map[string]any{"type": "text", "text": text})
+			}
+			var calls []struct {
+				ID       string `json:"id"`
+				Function struct {
+					Name      string          `json:"name"`
+					Arguments json.RawMessage `json:"arguments"`
+				} `json:"function"`
+			}
+			_ = json.Unmarshal(m.ToolCalls, &calls)
+			for _, c := range calls {
+				var input map[string]any
+				if err := json.Unmarshal(c.Function.Arguments, &input); err != nil {
+					input = map[string]any{"raw": string(c.Function.Arguments)}
+				}
+				content = append(content, map[string]any{
+					"type":  "tool_use",
+					"id":    c.ID,
+					"name":  c.Function.Name,
+					"input": input,
+				})
+			}
+			claudeMsgs = append(claudeMsgs, map[string]any{"role": "assistant", "content": content})
+			continue
+		}
+		// Tool role messages → tool_result blocks.
+		if m.Role == "tool" {
+			content := []map[string]any{{
+				"type":        "tool_result",
+				"tool_use_id": m.ToolCallID,
+				"content":     contentString(m.Content),
+			}}
+			claudeMsgs = append(claudeMsgs, map[string]any{"role": "user", "content": content})
+			continue
+		}
+		claudeMsgs = append(claudeMsgs, map[string]any{"role": m.Role, "content": contentString(m.Content)})
+	}
+	if len(claudeMsgs) == 0 {
+		claudeMsgs = append(claudeMsgs, map[string]any{"role": "user", "content": "Hi"})
+	}
+	body := map[string]any{"messages": claudeMsgs}
+	if system != "" {
+		body["system"] = system
+	}
+	return body, nil
+}
+
+// toolsToClaude converts OpenAI function tools to Claude tools.
+func toolsToClaude(tools []openai.Tool) []map[string]any {
+	out := []map[string]any{}
+	for _, t := range tools {
+		if t.Type != "" && t.Type != "function" {
+			continue
+		}
+		out = append(out, map[string]any{
+			"name":         t.Function.Name,
+			"description":  t.Function.Description,
+			"input_schema": json.RawMessage(t.Function.Parameters),
+		})
+	}
+	return out
+}
+
+// claudeToolsToOpenAI converts Claude tools to OpenAI function tools.
+func claudeToolsToOpenAI(tools json.RawMessage) []openai.Tool {
+	var list []struct {
+		Name        string          `json:"name"`
+		Description string          `json:"description"`
+		InputSchema json.RawMessage `json:"input_schema"`
+	}
+	if err := json.Unmarshal(tools, &list); err != nil {
+		return nil
+	}
+	out := []openai.Tool{}
+	for _, t := range list {
+		out = append(out, openai.Tool{
+			Type: "function",
+			Function: openai.FunctionTool{
+				Name:        t.Name,
+				Description: t.Description,
+				Parameters:  t.InputSchema,
+			},
+		})
+	}
+	return out
+}

server/internal/proxy/convert/convert.go

@@ -0,0 +1,357 @@
+package convert
+
+import (
+	"encoding/json"
+
+	"openteam/server/internal/proxy/claude"
+	"openteam/server/internal/proxy/openai"
+)
+
+// ClientProtocol mirrors the gateway's Protocol but kept here to avoid an
+// import cycle with the proxy package.
+type ClientProtocol string
+
+const (
+	ClientOpenAIChat     ClientProtocol = "openai-chat"
+	ClientOpenAIResponses ClientProtocol = "openai-responses"
+	ClientAnthropic      ClientProtocol = "anthropic"
+)
+
+// Request converts a request body from the client protocol to the channel
+// provider's native format.
+func Request(client ClientProtocol, provider string, body []byte, upstreamModel string) ([]byte, error) {
+	var canon *CanonicalRequest
+	var err error
+	switch client {
+	case ClientOpenAIChat:
+		canon, err = requestFromOpenAIChat(body)
+	case ClientOpenAIResponses:
+		canon, err = requestFromResponses(body)
+	case ClientAnthropic:
+		canon, err = requestFromClaude(body)
+	default:
+		return nil, jsonError("unsupported client protocol")
+	}
+	if err != nil {
+		return nil, err
+	}
+	canon.Model = upstreamModel
+	if canon.Model == "" {
+		canon.Model = ""
+	}
+
+	switch provider {
+	case "anthropic":
+		return canonicalToClaude(canon)
+	case "openai", "compatible":
+		return canonicalToOpenAIChat(canon)
+	default:
+		return nil, jsonError("unsupported provider")
+	}
+}
+
+// Response converts a non-stream upstream response into the client protocol.
+func Response(client ClientProtocol, provider string, body []byte) ([]byte, error) {
+	if client == ClientOpenAIChat && provider == "openai" {
+		return body, nil // passthrough
+	}
+	if client == ClientOpenAIResponses && provider == "openai" {
+		return body, nil
+	}
+	if client == ClientAnthropic && provider == "anthropic" {
+		return body, nil
+	}
+	if provider == "anthropic" {
+		var mr claude.MessageResponse
+		if err := json.Unmarshal(body, &mr); err != nil {
+			return nil, err
+		}
+		switch client {
+		case ClientOpenAIChat:
+			return claudeResponseToChat(&mr)
+		case ClientOpenAIResponses:
+			return claudeResponseToResponses(&mr)
+		}
+	}
+	if provider == "openai" || provider == "compatible" {
+		var cc openai.ChatCompletion
+		if err := json.Unmarshal(body, &cc); err != nil {
+			return nil, err
+		}
+		switch client {
+		case ClientAnthropic:
+			return chatResponseToClaude(&cc)
+		}
+	}
+	return nil, jsonError("no conversion path")
+}
+
+// canonicalToOpenAIChat re-emits the canonical request as OpenAI chat JSON.
+func canonicalToOpenAIChat(c *CanonicalRequest) ([]byte, error) {
+	obj := map[string]any{
+		"model":    c.Model,
+		"messages": c.Messages,
+	}
+	if c.Stream {
+		obj["stream"] = true
+	}
+	if c.Temperature != nil {
+		obj["temperature"] = *c.Temperature
+	}
+	if c.TopP != nil {
+		obj["top_p"] = *c.TopP
+	}
+	if c.MaxTokens != nil {
+		obj["max_tokens"] = *c.MaxTokens
+	}
+	if len(c.Stop) > 0 {
+		obj["stop"] = c.Stop
+	}
+	if len(c.Tools) > 0 {
+		obj["tools"] = c.Tools
+	}
+	if len(c.ToolChoice) > 0 {
+		obj["tool_choice"] = json.RawMessage(c.ToolChoice)
+	}
+	if len(c.ResponseFormat) > 0 {
+		obj["response_format"] = json.RawMessage(c.ResponseFormat)
+	}
+	for k, v := range c.RawOpenAIExtras {
+		obj[k] = json.RawMessage(v)
+	}
+	return json.Marshal(obj)
+}
+
+// canonicalToClaude emits the canonical request as an Anthropic Messages body.
+func canonicalToClaude(c *CanonicalRequest) ([]byte, error) {
+	body, err := chatToClaudeMessages(c.Messages, c.System)
+	if err != nil {
+		return nil, err
+	}
+	maxTokens := 4096
+	if c.MaxTokens != nil {
+		maxTokens = *c.MaxTokens
+	}
+	body["model"] = c.Model
+	body["max_tokens"] = maxTokens
+	if c.Stream {
+		body["stream"] = true
+	}
+	if c.Temperature != nil {
+		// Claude clamps temperature to [0,1].
+		t := *c.Temperature
+		if t > 1 {
+			t = 1
+		}
+		if t < 0 {
+			t = 0
+		}
+		body["temperature"] = t
+	}
+	if c.TopP != nil {
+		body["top_p"] = *c.TopP
+	}
+	if len(c.Stop) > 0 {
+		body["stop_sequences"] = c.Stop
+	}
+	if tools := toolsToClaude(c.Tools); len(tools) > 0 {
+		body["tools"] = tools
+	}
+	if len(c.ToolChoice) > 0 {
+		var tc json.RawMessage
+		if err := json.Unmarshal(c.ToolChoice, &tc); err == nil {
+			body["tool_choice"] = tc
+		}
+	}
+	return json.Marshal(body)
+}
+
+// claudeResponseToChat converts a Claude non-stream response to OpenAI chat.
+func claudeResponseToChat(mr *claude.MessageResponse) ([]byte, error) {
+	var blocks []struct {
+		Type    string          `json:"type"`
+		Text    string          `json:"text"`
+		ID      string          `json:"id"`
+		Name    string          `json:"name"`
+		Input   json.RawMessage `json:"input"`
+	}
+	_ = json.Unmarshal(mr.Content, &blocks)
+
+	content := ""
+	var toolCalls []map[string]any
+	for _, b := range blocks {
+		switch b.Type {
+		case "text":
+			if content == "" {
+				content = b.Text
+			} else {
+				content += b.Text
+			}
+		case "tool_use":
+			input, _ := json.Marshal(b.Input)
+			toolCalls = append(toolCalls, map[string]any{
+				"id":   b.ID,
+				"type": "function",
+				"function": map[string]any{
+					"name":      b.Name,
+					"arguments": string(input),
+				},
+			})
+		}
+	}
+	msg := map[string]any{"role": "assistant", "content": content}
+	if len(toolCalls) > 0 {
+		msg["tool_calls"] = toolCalls
+	}
+	finish := mapClaudeStopReason(mr.StopReason)
+	choices := []any{map[string]any{"index": 0, "message": msg, "finish_reason": finish}}
+	resp := map[string]any{
+		"id":      "chatcmpl-" + mr.ID,
+		"object":  "chat.completion",
+		"created": json.Number("0"),
+		"model":   mr.Model,
+		"choices": choices,
+	}
+	if mr.Usage != nil {
+		resp["usage"] = map[string]any{
+			"prompt_tokens":     mr.Usage.InputTokens,
+			"completion_tokens": mr.Usage.OutputTokens,
+			"total_tokens":      mr.Usage.InputTokens + mr.Usage.OutputTokens,
+		}
+	}
+	return json.Marshal(resp)
+}
+
+// chatResponseToClaude converts an OpenAI non-stream response to Claude.
+func chatResponseToClaude(cc *openai.ChatCompletion) ([]byte, error) {
+	content := []map[string]any{}
+	if len(cc.Choices) > 0 {
+		ch := cc.Choices[0]
+		if text := contentString(ch.Message.Content); text != "" {
+			content = append(content, map[string]any{"type": "text", "text": text})
+		}
+		if len(ch.Message.ToolCalls) > 0 {
+			var calls []struct {
+				ID       string `json:"id"`
+				Function struct {
+					Name      string          `json:"name"`
+					Arguments json.RawMessage `json:"arguments"`
+				} `json:"function"`
+			}
+			_ = json.Unmarshal(ch.Message.ToolCalls, &calls)
+			for _, call := range calls {
+				var input map[string]any
+				_ = json.Unmarshal(call.Function.Arguments, &input)
+				content = append(content, map[string]any{
+					"type":  "tool_use",
+					"id":    call.ID,
+					"name":  call.Function.Name,
+					"input": input,
+				})
+			}
+		}
+	}
+	resp := map[string]any{
+		"id":      mrID(cc.ID),
+		"type":    "message",
+		"role":    "assistant",
+		"model":   cc.Model,
+		"content": content,
+		"stop_reason": mapChatStopReason(cc),
+		"usage": map[string]any{
+			"input_tokens":  usageInt64(cc, true),
+			"output_tokens": usageInt64(cc, false),
+		},
+	}
+	return json.Marshal(resp)
+}
+
+// claudeResponseToResponses converts a Claude non-stream response to a
+// Responses API response.
+func claudeResponseToResponses(mr *claude.MessageResponse) ([]byte, error) {
+	chatCC := &openai.ChatCompletion{
+		ID:      mr.ID,
+		Model:   mr.Model,
+		Choices: []openai.ChatChoice{{FinishReason: mapClaudeStopReason(mr.StopReason)}},
+	}
+	// Reuse the chat conversion then re-shape into responses items.
+	chatBody, err := claudeResponseToChat(mr)
+	if err == nil {
+		var cc openai.ChatCompletion
+		if json.Unmarshal(chatBody, &cc) == nil {
+			chatCC = &cc
+		}
+	}
+	items, status := chatToResponsesOutput(chatCC)
+	resp := map[string]any{
+		"id":      "resp_" + mr.ID,
+		"object":  "response",
+		"created": json.Number("0"),
+		"model":   mr.Model,
+		"status":  status,
+		"output":  items,
+	}
+	if mr.Usage != nil {
+		resp["usage"] = map[string]any{
+			"input_tokens":  mr.Usage.InputTokens,
+			"output_tokens": mr.Usage.OutputTokens,
+			"total_tokens":  mr.Usage.InputTokens + mr.Usage.OutputTokens,
+			"input_tokens_details": map[string]any{
+				"cached_tokens": mr.Usage.CacheReadInputTokens,
+			},
+		}
+	}
+	return json.Marshal(resp)
+}
+
+func mapClaudeStopReason(reason string) string {
+	switch reason {
+	case "end_turn":
+		return "stop"
+	case "max_tokens":
+		return "length"
+	case "stop_sequence":
+		return "stop"
+	case "tool_use":
+		return "tool_calls"
+	case "refusal":
+		return "content_filter"
+	default:
+		return "stop"
+	}
+}
+
+func mapChatStopReason(cc *openai.ChatCompletion) string {
+	if len(cc.Choices) == 0 {
+		return "end_turn"
+	}
+	switch cc.Choices[0].FinishReason {
+	case "stop":
+		return "end_turn"
+	case "length":
+		return "max_tokens"
+	case "tool_calls":
+		return "tool_use"
+	case "content_filter":
+		return "refusal"
+	default:
+		return "end_turn"
+	}
+}
+
+func usageInt64(cc *openai.ChatCompletion, input bool) int64 {
+	if cc.Usage == nil {
+		return 0
+	}
+	if input {
+		return cc.Usage.PromptTokens
+	}
+	return cc.Usage.CompletionTokens
+}
+
+func mrID(id string) string {
+	if id == "" {
+		return "msg_unknown"
+	}
+	return id
+}

server/internal/proxy/convert/responses.go

@@ -0,0 +1,161 @@
+package convert
+
+import (
+	"encoding/json"
+	"errors"
+
+	"openteam/server/internal/proxy/openai"
+)
+
+// responsesInputToChat converts Responses API input items into chat messages.
+func responsesInputToChat(raw json.RawMessage) ([]openai.ChatMessage, error) {
+	var msgs []openai.ChatMessage
+
+	// `input` may be a plain string.
+	var s string
+	if json.Unmarshal(raw, &s) == nil {
+		content, _ := json.Marshal(s)
+		msgs = append(msgs, openai.ChatMessage{Role: "user", Content: content})
+		return msgs, nil
+	}
+
+	// Or an array of content parts (text/image).
+	var parts []map[string]json.RawMessage
+	if json.Unmarshal(raw, &parts) == nil {
+		chat, err := contentPartsToChat(parts)
+		if err == nil {
+			return chat, nil
+		}
+	}
+
+	var items []map[string]json.RawMessage
+	if err := json.Unmarshal(raw, &items); err != nil {
+		return nil, err
+	}
+	for _, item := range items {
+		var typ string
+		_ = json.Unmarshal(item["type"], &typ)
+		switch typ {
+		case "message":
+			var role string
+			_ = json.Unmarshal(item["role"], &role)
+			content, err := contentPartsToText(item["content"])
+			if err != nil {
+				continue
+			}
+			msgs = append(msgs, openai.ChatMessage{Role: role, Content: content})
+		case "function_call":
+			tc := map[string]any{
+				"id":   rawString(item["call_id"]),
+				"type": "function",
+				"function": map[string]any{
+					"name":      rawString(item["name"]),
+					"arguments": rawString(item["arguments"]),
+				},
+			}
+			tcArr, _ := json.Marshal([]any{tc})
+			msgs = append(msgs, openai.ChatMessage{Role: "assistant", ToolCalls: tcArr})
+		case "function_call_output":
+			content, _ := json.Marshal(rawString(item["output"]))
+			msgs = append(msgs, openai.ChatMessage{Role: "tool", ToolCallID: rawString(item["call_id"]), Content: content})
+		case "reasoning", "computer_call", "web_search_call":
+			// Not representable in chat; drop.
+		}
+	}
+	if len(msgs) == 0 {
+		content, _ := json.Marshal("")
+		msgs = append(msgs, openai.ChatMessage{Role: "user", Content: content})
+	}
+	return msgs, nil
+}
+
+// contentPartsToText flattens an array of content parts into a string.
+func contentPartsToText(raw json.RawMessage) (json.RawMessage, error) {
+	var parts []map[string]json.RawMessage
+	if err := json.Unmarshal(raw, &parts); err != nil {
+		var s string
+		if err := json.Unmarshal(raw, &s); err == nil {
+			c, _ := json.Marshal(s)
+			return c, nil
+		}
+		return nil, err
+	}
+	var buf string
+	for _, p := range parts {
+		var typ string
+		_ = json.Unmarshal(p["type"], &typ)
+		switch typ {
+		case "input_text", "output_text", "text":
+			buf += rawString(p["text"])
+		}
+	}
+	c, _ := json.Marshal(buf)
+	return c, nil
+}
+
+func contentPartsToChat(parts []map[string]json.RawMessage) ([]openai.ChatMessage, error) {
+	out := []map[string]any{}
+	for _, p := range parts {
+		var typ string
+		_ = json.Unmarshal(p["type"], &typ)
+		switch typ {
+		case "input_text", "output_text", "text":
+			out = append(out, map[string]any{"type": "text", "text": rawString(p["text"])})
+		case "input_image":
+			out = append(out, map[string]any{
+				"type": "image_url",
+				"image_url": map[string]any{
+					"url": "data:" + rawString(p["media_type"]) + ";base64," + rawString(p["image_url"]),
+				},
+			})
+		}
+	}
+	if len(out) == 0 {
+		return nil, jsonError("empty content")
+	}
+	arr, _ := json.Marshal(out)
+	msg := openai.ChatMessage{Role: "user", Content: arr}
+	return []openai.ChatMessage{msg}, nil
+}
+
+// chatToResponsesOutput builds Responses output items from a chat completion.
+func chatToResponsesOutput(cc *openai.ChatCompletion) ([]map[string]any, string) {
+	var items []map[string]any
+	var status = "completed"
+	if len(cc.Choices) == 0 {
+		return items, status
+	}
+	ch := cc.Choices[0]
+	if ch.FinishReason == "length" {
+		status = "incomplete"
+	}
+	content := []map[string]any{}
+	if text := contentString(ch.Message.Content); text != "" {
+		content = append(content, map[string]any{"type": "output_text", "text": text})
+	}
+	items = append(items, map[string]any{"type": "message", "role": "assistant", "content": content})
+	if len(ch.Message.ToolCalls) > 0 {
+		var calls []struct {
+			ID       string `json:"id"`
+			Function struct {
+				Name      string          `json:"name"`
+				Arguments json.RawMessage `json:"arguments"`
+			} `json:"function"`
+		}
+		if json.Unmarshal(ch.Message.ToolCalls, &calls) == nil {
+			for _, call := range calls {
+				items = append(items, map[string]any{
+					"type":      "function_call",
+					"call_id":   call.ID,
+					"name":      call.Function.Name,
+					"arguments": rawString(call.Function.Arguments),
+				})
+			}
+		}
+	}
+	return items, status
+}
+
+func jsonError(msg string) error {
+	return errors.New(msg)
+}

server/internal/proxy/convert/stream.go

@@ -0,0 +1,416 @@
+package convert
+
+import (
+	"encoding/json"
+
+	"openteam/server/internal/proxy/claude"
+	"openteam/server/internal/proxy/openai"
+	"openteam/server/internal/proxy/stream"
+)
+
+// Usage is the streaming token usage snapshot.
+type Usage struct {
+	Input         int64
+	Output        int64
+	CacheRead     int64
+	CacheCreation int64
+}
+
+// Translator converts SSE events from an upstream stream into client frames.
+type Translator interface {
+	// Feed handles one upstream SSE event, returning client frames to write.
+	Feed(ev stream.SSEEvent) ([]stream.SSEEvent, error)
+	// Finish is called at end-of-stream, returning final frames.
+	Finish() ([]stream.SSEEvent, error)
+	// Usage returns the latest known usage.
+	Usage() *Usage
+}
+
+// claudeToChatTranslator converts a Claude stream to OpenAI chat chunks.
+type claudeToChatTranslator struct {
+	model          string
+	usage          *Usage
+	started        bool
+	finishSent     bool
+	toolCallIndex  int
+	toolCallID     string
+	toolCallName   string
+}
+
+func (t *claudeToChatTranslator) Feed(ev stream.SSEEvent) ([]stream.SSEEvent, error) {
+	if ev.Done {
+		return nil, nil
+	}
+	var e claude.StreamEvent
+	if err := json.Unmarshal([]byte(ev.Data), &e); err != nil {
+		return nil, nil
+	}
+	var out []stream.SSEEvent
+
+	switch e.Type {
+	case "message_start":
+		if e.Message != nil {
+			var msg struct {
+				Model string `json:"model"`
+			}
+			_ = json.Unmarshal(e.Message, &msg)
+			t.model = msg.Model
+		}
+		chunk, _ := json.Marshal(openai.ChatChunk{
+			ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+			Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{Role: "assistant"}}},
+		})
+		out = append(out, stream.SSEEvent{Data: string(chunk)})
+		t.started = true
+
+	case "content_block_start":
+		var cb struct {
+			Index int             `json:"index"`
+			Block json.RawMessage `json:"content_block"`
+		}
+		_ = json.Unmarshal([]byte(ev.Data), &cb)
+		var block struct {
+			Type  string `json:"type"`
+			ID    string `json:"id"`
+			Name  string `json:"name"`
+		}
+		_ = json.Unmarshal(cb.Block, &block)
+		if block.Type == "tool_use" {
+			t.toolCallIndex = cb.Index
+			t.toolCallID = block.ID
+			t.toolCallName = block.Name
+			tc, _ := json.Marshal([]map[string]any{{
+				"index": cb.Index, "id": block.ID, "type": "function",
+				"function": map[string]any{"name": block.Name, "arguments": ""},
+			}})
+			chunk, _ := json.Marshal(openai.ChatChunk{
+				ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+				Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{ToolCalls: tc}}},
+			})
+			out = append(out, stream.SSEEvent{Data: string(chunk)})
+		}
+
+	case "content_block_delta":
+		var d struct {
+			Index int             `json:"index"`
+			Delta json.RawMessage `json:"delta"`
+		}
+		_ = json.Unmarshal([]byte(ev.Data), &d)
+		var delta struct {
+			Type string `json:"type"`
+			Text string `json:"text"`
+			PartialJSON string `json:"partial_json"`
+		}
+		_ = json.Unmarshal(d.Delta, &delta)
+		if delta.Type == "text_delta" && delta.Text != "" {
+			chunk, _ := json.Marshal(openai.ChatChunk{
+				ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+				Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{Content: delta.Text}}},
+			})
+			out = append(out, stream.SSEEvent{Data: string(chunk)})
+		} else if delta.Type == "input_json_delta" && delta.PartialJSON != "" {
+			tc, _ := json.Marshal([]map[string]any{{
+				"index": d.Index, "function": map[string]any{"arguments": delta.PartialJSON},
+			}})
+			chunk, _ := json.Marshal(openai.ChatChunk{
+				ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+				Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{ToolCalls: tc}}},
+			})
+			out = append(out, stream.SSEEvent{Data: string(chunk)})
+		}
+
+	case "message_delta":
+		var d struct {
+			Delta json.RawMessage `json:"delta"`
+			Usage json.RawMessage `json:"usage"`
+		}
+		_ = json.Unmarshal([]byte(ev.Data), &d)
+		if len(d.Usage) > 0 {
+			var u claude.Usage
+			if json.Unmarshal(d.Usage, &u) == nil {
+				t.usage = &Usage{
+					Input: u.InputTokens, Output: u.OutputTokens,
+					CacheRead: u.CacheReadInputTokens, CacheCreation: u.CacheCreationInputTokens,
+				}
+			}
+		}
+		if len(d.Delta) > 0 && !t.finishSent {
+			var delta struct {
+				StopReason string `json:"stop_reason"`
+			}
+			_ = json.Unmarshal(d.Delta, &delta)
+			if delta.StopReason != "" {
+				reason := mapClaudeStopReason(delta.StopReason)
+				chunk, _ := json.Marshal(openai.ChatChunk{
+					ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+					Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{}, FinishReason: &reason}},
+				})
+				out = append(out, stream.SSEEvent{Data: string(chunk)})
+				t.finishSent = true
+			}
+		}
+	}
+	return out, nil
+}
+
+func (t *claudeToChatTranslator) Finish() ([]stream.SSEEvent, error) {
+	if !t.finishSent {
+		reason := "stop"
+		chunk, _ := json.Marshal(openai.ChatChunk{
+			ID: "chatcmpl-stream", Object: "chat.completion.chunk", Model: t.model,
+			Choices: []openai.ChatChunkChoice{{Index: 0, Delta: openai.ChatDelta{}, FinishReason: &reason}},
+		})
+		t.finishSent = true
+		return []stream.SSEEvent{{Data: string(chunk)}, {Data: "[DONE]"}}, nil
+	}
+	return []stream.SSEEvent{{Data: "[DONE]"}}, nil
+}
+
+func (t *claudeToChatTranslator) Usage() *Usage { return t.usage }
+
+// chatToClaudeTranslator converts an OpenAI chat stream to Claude events.
+type chatToClaudeTranslator struct {
+	usage          *Usage
+	started        bool
+	openBlock      bool
+	blockType      string
+	toolIndex      int
+	finishSent     bool
+}
+
+func (t *chatToClaudeTranslator) Feed(ev stream.SSEEvent) ([]stream.SSEEvent, error) {
+	if ev.Done {
+		return nil, nil
+	}
+	var chunk openai.ChatChunk
+	if err := json.Unmarshal([]byte(ev.Data), &chunk); err != nil {
+		return nil, nil
+	}
+	if chunk.Usage != nil {
+		t.usage = &Usage{Input: chunk.Usage.PromptTokens, Output: chunk.Usage.CompletionTokens}
+	}
+	var out []stream.SSEEvent
+	if len(chunk.Choices) == 0 {
+		return out, nil
+	}
+	ch := chunk.Choices[0]
+
+	if !t.started {
+		msg, _ := json.Marshal(map[string]any{
+			"id": "msg_stream", "type": "message", "role": "assistant",
+			"model": chunk.Model, "content": []any{},
+		})
+		start, _ := json.Marshal(map[string]any{"type": "message_start", "message": json.RawMessage(msg)})
+		out = append(out, stream.SSEEvent{Data: string(start)})
+		t.started = true
+	}
+
+	if ch.Delta.Content != "" {
+		if !t.openBlock || t.blockType != "text" {
+			start, _ := json.Marshal(map[string]any{
+				"type": "content_block_start", "index": 0,
+				"content_block": map[string]any{"type": "text", "text": ""},
+			})
+			out = append(out, stream.SSEEvent{Data: string(start)})
+			t.openBlock = true
+			t.blockType = "text"
+			t.toolIndex = 0
+		}
+		delta, _ := json.Marshal(map[string]any{
+			"type": "content_block_delta", "index": 0,
+			"delta": map[string]any{"type": "text_delta", "text": ch.Delta.Content},
+		})
+		out = append(out, stream.SSEEvent{Data: string(delta)})
+	}
+
+	if len(ch.Delta.ToolCalls) > 0 {
+		var calls []struct {
+			Index    *int   `json:"index"`
+			ID       string `json:"id"`
+			Function struct {
+				Name      string `json:"name"`
+				Arguments string `json:"arguments"`
+			} `json:"function"`
+		}
+		_ = json.Unmarshal(ch.Delta.ToolCalls, &calls)
+		for _, call := range calls {
+			idx := 0
+			if call.Index != nil {
+				idx = *call.Index
+			}
+			if !t.openBlock || t.blockType != "tool_use" || idx != t.toolIndex {
+				start, _ := json.Marshal(map[string]any{
+					"type": "content_block_start", "index": idx,
+					"content_block": map[string]any{
+						"type": "tool_use", "id": call.ID, "name": call.Function.Name, "input": map[string]any{},
+					},
+				})
+				out = append(out, stream.SSEEvent{Data: string(start)})
+				t.openBlock = true
+				t.blockType = "tool_use"
+				t.toolIndex = idx
+			}
+			if call.Function.Arguments != "" {
+				delta, _ := json.Marshal(map[string]any{
+					"type": "content_block_delta", "index": idx,
+					"delta": map[string]any{"type": "input_json_delta", "partial_json": call.Function.Arguments},
+				})
+				out = append(out, stream.SSEEvent{Data: string(delta)})
+			}
+		}
+	}
+
+	if ch.FinishReason != nil && !t.finishSent {
+		reason := mapChatStopReasonToClaude(*ch.FinishReason)
+		md, _ := json.Marshal(map[string]any{
+			"type": "message_delta",
+			"delta": map[string]any{"stop_reason": reason, "stop_sequence": nil},
+		})
+		out = append(out, stream.SSEEvent{Data: string(md)})
+		t.finishSent = true
+	}
+	return out, nil
+}
+
+func (t *chatToClaudeTranslator) Finish() ([]stream.SSEEvent, error) {
+	if !t.finishSent {
+		md, _ := json.Marshal(map[string]any{
+			"type": "message_delta",
+			"delta": map[string]any{"stop_reason": "end_turn", "stop_sequence": nil},
+		})
+		t.finishSent = true
+		return []stream.SSEEvent{{Data: string(md)}, {Data: "{\"type\":\"message_stop\"}"}}, nil
+	}
+	return []stream.SSEEvent{{Data: "{\"type\":\"message_stop\"}"}}, nil
+}
+
+func (t *chatToClaudeTranslator) Usage() *Usage { return t.usage }
+
+// claudeToResponsesTranslator converts a Claude stream to Responses events.
+type claudeToResponsesTranslator struct {
+	usage      *Usage
+	model      string
+	completed  bool
+}
+
+func (t *claudeToResponsesTranslator) Feed(ev stream.SSEEvent) ([]stream.SSEEvent, error) {
+	if ev.Done {
+		return nil, nil
+	}
+	var e claude.StreamEvent
+	if err := json.Unmarshal([]byte(ev.Data), &e); err != nil {
+		return nil, nil
+	}
+	var out []stream.SSEEvent
+	switch e.Type {
+	case "message_start":
+		if e.Message != nil {
+			var msg struct {
+				Model string `json:"model"`
+			}
+			_ = json.Unmarshal(e.Message, &msg)
+			t.model = msg.Model
+		}
+		created, _ := json.Marshal(map[string]any{
+			"type": "response.created",
+			"response": map[string]any{"id": "resp_stream", "object": "response", "status": "in_progress", "model": t.model, "output": []any{}},
+		})
+		out = append(out, stream.SSEEvent{Data: string(created)})
+	case "content_block_delta":
+		var d struct {
+			Index int             `json:"index"`
+			Delta json.RawMessage `json:"delta"`
+		}
+		_ = json.Unmarshal([]byte(ev.Data), &d)
+		var delta struct {
+			Type string `json:"type"`
+			Text string `json:"text"`
+		}
+		_ = json.Unmarshal(d.Delta, &delta)
+		if delta.Type == "text_delta" && delta.Text != "" {
+			item, _ := json.Marshal(map[string]any{
+				"type": "response.output_text.delta", "item_id": "msg_stream", "output_index": 0,
+				"delta": delta.Text,
+			})
+			out = append(out, stream.SSEEvent{Data: string(item)})
+		}
+	case "message_delta":
+		var d struct {
+			Usage json.RawMessage `json:"usage"`
+		}
+		_ = json.Unmarshal([]byte(ev.Data), &d)
+		if len(d.Usage) > 0 {
+			var u claude.Usage
+			if json.Unmarshal(d.Usage, &u) == nil {
+				t.usage = &Usage{
+					Input: u.InputTokens, Output: u.OutputTokens,
+					CacheRead: u.CacheReadInputTokens, CacheCreation: u.CacheCreationInputTokens,
+				}
+			}
+		}
+		if !t.completed {
+			item, _ := json.Marshal(map[string]any{
+				"type": "response.completed",
+				"response": map[string]any{
+					"id": "resp_stream", "object": "response", "status": "completed", "model": t.model,
+					"output": []map[string]any{{"type": "message", "role": "assistant", "content": []any{}}},
+				},
+			})
+			out = append(out, stream.SSEEvent{Data: string(item)})
+			t.completed = true
+		}
+	}
+	return out, nil
+}
+
+func (t *claudeToResponsesTranslator) Finish() ([]stream.SSEEvent, error) {
+	if !t.completed {
+		item, _ := json.Marshal(map[string]any{
+			"type": "response.completed",
+			"response": map[string]any{
+				"id": "resp_stream", "object": "response", "status": "completed", "model": t.model,
+				"output": []map[string]any{{"type": "message", "role": "assistant", "content": []any{}}},
+			},
+		})
+		t.completed = true
+		return []stream.SSEEvent{{Data: string(item)}, {Data: "[DONE]"}}, nil
+	}
+	return []stream.SSEEvent{{Data: "[DONE]"}}, nil
+}
+
+func (t *claudeToResponsesTranslator) Usage() *Usage { return t.usage }
+
+func mapChatStopReasonToClaude(reason string) string {
+	switch reason {
+	case "stop":
+		return "end_turn"
+	case "length":
+		return "max_tokens"
+	case "tool_calls":
+		return "tool_use"
+	case "content_filter":
+		return "refusal"
+	default:
+		return "end_turn"
+	}
+}
+
+// NewTranslator returns the stream translator for a client protocol +
+// upstream provider pair, or nil for passthrough (no translation needed).
+func NewTranslator(client ClientProtocol, provider string) Translator {
+	switch client {
+	case ClientOpenAIChat:
+		if provider == "anthropic" {
+			return &claudeToChatTranslator{}
+		}
+	case ClientOpenAIResponses:
+		if provider == "anthropic" {
+			return &claudeToResponsesTranslator{}
+		}
+	case ClientAnthropic:
+		if provider == "openai" || provider == "compatible" {
+			return &chatToClaudeTranslator{}
+		}
+	}
+	return nil
+}

server/internal/proxy/convert_wrappers.go

@@ -0,0 +1,17 @@
+package proxy
+
+import (
+	"openteam/server/internal/proxy/convert"
+)
+
+// convertRequest translates a request body from the client protocol to the
+// channel provider's native format.
+func convertRequest(route Route, provider string, body []byte, upstreamModel string) ([]byte, error) {
+	return convert.Request(clientProto(route), provider, body, upstreamModel)
+}
+
+// convertResponse translates a non-stream upstream response back to the
+// client protocol.
+func convertResponse(route Route, provider string, body []byte) ([]byte, error) {
+	return convert.Response(clientProto(route), provider, body)
+}

server/internal/proxy/gateway.go

@@ -0,0 +1,414 @@
+package proxy
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/apikey"
+	"openteam/server/internal/billing"
+	"openteam/server/internal/channel"
+	"openteam/server/internal/config"
+	"openteam/server/internal/pkg/ratelimit"
+	"openteam/server/internal/usage"
+	"openteam/server/internal/store"
+)
+
+// Protocol identifies the client-facing API protocol.
+type Protocol string
+
+const (
+	ProtocolOpenAIChat     Protocol = "openai-chat"
+	ProtocolOpenAIResponses Protocol = "openai-responses"
+	ProtocolAnthropic      Protocol = "anthropic"
+)
+
+// Route describes one proxied endpoint.
+type Route struct {
+	Protocol Protocol
+	UpstreamPath string // suffix after base URL, e.g. /v1/chat/completions
+	NativeProvider string // provider type that matches this protocol ("openai" | "anthropic")
+}
+
+var Routes = []Route{
+	{Protocol: ProtocolOpenAIChat, UpstreamPath: "/v1/chat/completions", NativeProvider: "openai"},
+	{Protocol: ProtocolOpenAIResponses, UpstreamPath: "/v1/responses", NativeProvider: "openai"},
+	{Protocol: ProtocolAnthropic, UpstreamPath: "/v1/messages", NativeProvider: "anthropic"},
+}
+
+const maxBodyBytes = 16 << 20 // 16 MiB
+
+type Gateway struct {
+	db      *gorm.DB
+	cfg     *config.Config
+	log     *zap.Logger
+	channel *channel.Service
+	billing *billing.Service
+	usage   *usage.Service
+	apiKeys *apikey.Service
+	limiter *ratelimit.Limiter
+	client  *http.Client
+}
+
+func NewGateway(db *gorm.DB, cfg *config.Config, log *zap.Logger,
+	ch *channel.Service, bill *billing.Service, use *usage.Service, ak *apikey.Service) *Gateway {
+	return &Gateway{
+		db: db, cfg: cfg, log: log,
+		channel: ch, billing: bill, usage: use, apiKeys: ak,
+		limiter: ratelimit.New(float64(cfg.RateLimit.RequestsPerMin)/60.0, cfg.RateLimit.Burst),
+		client: &http.Client{
+			// Transport-level timeout; stream reads rely on the context so a
+			// connected-but-silent upstream is still bounded.
+			Timeout: time.Duration(cfg.Proxy.DefaultTimeoutMs) * time.Millisecond,
+		},
+	}
+}
+
+// authContext carries the authenticated key + user through a proxy request.
+type authContext struct {
+	key  *store.ApiKey
+	user *store.User
+}
+
+// Handle builds a gin handler for a route.
+func (g *Gateway) Handle(route Route) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		g.proxy(c, route)
+	}
+}
+
+func (g *Gateway) proxy(c *gin.Context, route Route) {
+	start := time.Now()
+	reqID := uuid.NewString()
+	c.Header("X-Request-Id", reqID)
+
+	auth, err := g.authenticate(c)
+	if err != nil {
+		g.writeProxyError(c, route.Protocol, http.StatusUnauthorized, "invalid API key")
+		return
+	}
+
+	body, err := io.ReadAll(io.LimitReader(c.Request.Body, maxBodyBytes))
+	if err != nil {
+		g.writeProxyError(c, route.Protocol, http.StatusBadRequest, "failed to read request body")
+		return
+	}
+	if len(body) == 0 {
+		g.writeProxyError(c, route.Protocol, http.StatusBadRequest, "empty request body")
+		return
+	}
+
+	var meta struct {
+		Model  string `json:"model"`
+		Stream bool   `json:"stream"`
+	}
+	if err := json.Unmarshal(body, &meta); err != nil {
+		g.writeProxyError(c, route.Protocol, http.StatusBadRequest, "invalid JSON body: "+err.Error())
+		return
+	}
+	if meta.Model == "" {
+		g.writeProxyError(c, route.Protocol, http.StatusBadRequest, "missing model field")
+		return
+	}
+
+	// Per-key model whitelist.
+	if len(auth.key.AllowedModels) > 0 && !contains(auth.key.AllowedModels, meta.Model) {
+		g.writeProxyError(c, route.Protocol, http.StatusForbidden,
+			"model not allowed for this API key: "+meta.Model)
+		return
+	}
+
+	// Rate limit (user + key).
+	if !g.limiter.Allow(fmt.Sprintf("u:%d", auth.user.ID)) {
+		g.writeProxyError(c, route.Protocol, http.StatusTooManyRequests, "rate limit exceeded")
+		return
+	}
+	if !g.limiter.Allow(fmt.Sprintf("k:%d", auth.key.ID)) {
+		g.writeProxyError(c, route.Protocol, http.StatusTooManyRequests, "key rate limit exceeded")
+		return
+	}
+
+	// Resolve model.
+	model, err := g.channel.ResolveModel(meta.Model)
+	if err != nil {
+		g.writeProxyError(c, route.Protocol, http.StatusNotFound, err.Error())
+		return
+	}
+
+	// Channel attempts with failover: on transport/5xx failures the request is
+	// retried against another channel bound to the same model.
+	exclude := map[int64]bool{}
+	attempts := 1 + g.cfg.Proxy.MaxRetries
+	if attempts < 1 {
+		attempts = 1
+	}
+	var lastCh *store.Channel
+	formatBlocked := false
+	attempted := false
+	for attempt := 0; attempt < attempts; attempt++ {
+		ch, binding, err := g.channel.SelectChannel(model.ID, exclude)
+		if err != nil {
+			// Every bound channel was skipped for format reasons: say so
+			// clearly instead of reporting a generic upstream failure.
+			if formatBlocked && !attempted {
+				g.writeProxyError(c, route.Protocol, http.StatusBadRequest,
+					"no channel supports the "+string(route.Protocol)+" API format")
+				return
+			}
+			if attempt == 0 {
+				g.writeProxyError(c, route.Protocol, http.StatusServiceUnavailable, "no available channel for model")
+			} else {
+				g.recordError(reqID, auth, model, lastCh, start, "upstream_error")
+				g.writeProxyError(c, route.Protocol, http.StatusBadGateway, "all upstream channels failed")
+			}
+			return
+		}
+		exclude[ch.ID] = true
+		lastCh = ch
+
+		// Skip channels that cannot serve this protocol at all (no native
+		// support and no conversion path).
+		if !channelServesFormat(ch, route) {
+			formatBlocked = true
+			g.log.Debug("channel cannot serve protocol",
+				zap.String("protocol", string(route.Protocol)), zap.Int64("channel_id", ch.ID))
+			continue
+		}
+
+		// Optional balance pre-check with an estimate.
+		if g.cfg.Proxy.BillingExactBalance {
+			estIn := int64(len(body) / 4)
+			estOut := int64(512)
+			if meta.Stream {
+				estOut = int64(g.cfg.Proxy.DefaultMaxTokens)
+			}
+			est, cerr := g.billing.EstimateCost(model.ID, estIn, estOut, 0)
+			if cerr == nil {
+				if berr := g.billing.CheckBalance(auth.user.ID, est); berr != nil {
+					g.recordError(reqID, auth, model, ch, start, "insufficient_balance")
+					g.writeProxyError(c, route.Protocol, http.StatusPaymentRequired, "insufficient balance")
+					return
+				}
+			}
+		}
+
+		upstreamKey, err := g.channel.DecryptKey(ch.APIKeyEnc)
+		if err != nil {
+			g.log.Error("decrypt channel key", zap.Error(err), zap.Int64("channel_id", ch.ID))
+			g.writeProxyError(c, route.Protocol, http.StatusBadGateway, "channel key unavailable")
+			return
+		}
+
+		release, err := g.channel.Acquire(ch.ID)
+		if err != nil {
+			g.writeProxyError(c, route.Protocol, http.StatusServiceUnavailable, "channel unavailable")
+			return
+		}
+		attempted = true
+		retryable := g.forward(c, route, meta.Model, ch, binding.UpstreamModel, upstreamKey, body, start, reqID, auth, model)
+		release()
+		if !retryable {
+			return
+		}
+		g.log.Warn("upstream failed, retrying on another channel",
+			zap.Int64("model_id", model.ID), zap.Int64("channel_id", ch.ID), zap.Int("attempt", attempt+1))
+	}
+	if formatBlocked && !attempted {
+		g.writeProxyError(c, route.Protocol, http.StatusBadRequest,
+			"no channel supports the "+string(route.Protocol)+" API format")
+		return
+	}
+	g.recordError(reqID, auth, model, lastCh, start, "upstream_error")
+	g.writeProxyError(c, route.Protocol, http.StatusBadGateway, "all upstream channels failed")
+}
+
+// forward decides passthrough vs conversion and calls the upstream.
+// It returns true when the failure is retryable on another channel.
+func (g *Gateway) forward(c *gin.Context, route Route, clientModel string,
+	ch *store.Channel, upstreamModel, upstreamKey string, body []byte,
+	start time.Time, reqID string, auth *authContext, model *store.Model) bool {
+
+	upstreamBody, converted := g.prepareUpstreamBody(route, ch, body, upstreamModel)
+	if converted {
+		c.Header("x-converted", "true")
+	}
+
+	// Build upstream request bound to the client context so disconnects cancel it.
+	ctx := c.Request.Context()
+	upstreamURL := strings.TrimSuffix(ch.BaseURL, "/") + upstreamPath(route, ch)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, upstreamURL, bytes.NewReader(upstreamBody))
+	if err != nil {
+		g.writeProxyError(c, route.Protocol, http.StatusBadGateway, "failed to build upstream request")
+		return false
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+upstreamKey)
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("X-Request-Id", reqID)
+	// Explicitly drop hop-by-hop / auth-ish headers we don't want forwarded.
+	copyProxyHeaders(c, req)
+
+	resp, err := g.client.Do(req)
+	if err != nil {
+		// Client disconnect vs upstream failure.
+		if errors.Is(ctx.Err(), context.Canceled) {
+			g.recordCanceled(reqID, auth, model, ch, start)
+			return false
+		}
+		g.log.Warn("upstream request failed", zap.Error(err), zap.Int64("channel_id", ch.ID))
+		return true
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 500 {
+		errBody, _ := io.ReadAll(resp.Body)
+		g.log.Warn("upstream returned 5xx", zap.Int("status", resp.StatusCode),
+			zap.Int64("channel_id", ch.ID), zap.String("body", truncateText(string(errBody), 512)))
+		return true
+	}
+	if resp.StatusCode >= 400 {
+		errBody, _ := io.ReadAll(resp.Body)
+		g.recordError(reqID, auth, model, ch, start, "upstream_"+strconv.Itoa(resp.StatusCode))
+		g.writeUpstreamError(c, route.Protocol, resp.StatusCode, errBody)
+		return false
+	}
+
+	streaming := bodyStreamFlag(body, route)
+	if streaming {
+		g.streamResponse(c, route, resp, start, reqID, auth, model, ch)
+	} else {
+		g.plainResponse(c, route, resp, start, reqID, auth, model, ch)
+	}
+	return false
+}
+
+// prepareUpstreamBody rewrites the model name, or converts the body when the
+// channel does not serve the client protocol natively. Returns the payload and
+// whether any conversion happened.
+func (g *Gateway) prepareUpstreamBody(route Route, ch *store.Channel, body []byte, upstreamModel string) ([]byte, bool) {
+	if ch.SupportsFormat(string(route.Protocol)) {
+		if upstreamModel == "" || sameModel(body, upstreamModel) {
+			return body, false
+		}
+		rewritten, err := setModelField(body, upstreamModel)
+		if err != nil {
+			return body, false
+		}
+		return rewritten, true
+	}
+	converted, err := convertRequest(route, ch.Provider, body, upstreamModel)
+	if err != nil {
+		g.log.Warn("request conversion failed, falling back to passthrough",
+			zap.Error(err), zap.String("route", string(route.Protocol)), zap.String("provider", ch.Provider))
+		return body, false
+	}
+	return converted, true
+}
+
+// streamResponse forwards an SSE stream to the client while extracting usage.
+func (g *Gateway) streamResponse(c *gin.Context, route Route, resp *http.Response,
+	start time.Time, reqID string, auth *authContext, model *store.Model, ch *store.Channel) {
+
+	c.Header("Content-Type", "text/event-stream")
+	c.Header("Cache-Control", "no-cache")
+	c.Header("Connection", "keep-alive")
+
+	if upstreamProvider(route, ch) == "anthropic" {
+		g.streamAnthropic(c, route, resp, start, reqID, auth, model, ch)
+		return
+	}
+	g.streamOpenAI(c, route, resp, start, reqID, auth, model, ch)
+}
+
+// plainResponse buffers a non-stream upstream response and returns it.
+func (g *Gateway) plainResponse(c *gin.Context, route Route, resp *http.Response,
+	start time.Time, reqID string, auth *authContext, model *store.Model, ch *store.Channel) {
+
+	raw, err := io.ReadAll(resp.Body)
+	if err != nil {
+		g.log.Warn("read upstream body", zap.Error(err))
+		g.writeProxyError(c, route.Protocol, http.StatusBadGateway, "failed to read upstream response")
+		return
+	}
+
+	out := raw
+	usageInfo := parseUsageForProtocol(route.Protocol, raw)
+	if !ch.SupportsFormat(string(route.Protocol)) {
+		converted, cerr := convertResponse(route, ch.Provider, raw)
+		if cerr == nil {
+			out = converted
+			usageInfo = parseUsageForProtocol(route.Protocol, out)
+			c.Header("x-converted", "true")
+		} else {
+			g.log.Warn("response conversion failed, forwarding raw",
+				zap.Error(cerr), zap.String("protocol", string(route.Protocol)))
+		}
+	}
+	c.Data(http.StatusOK, "application/json", out)
+	g.afterComplete(start, reqID, auth, model, ch, usageInfo, "success", "")
+}
+
+// afterComplete performs billing and usage accounting for a finished request.
+func (g *Gateway) afterComplete(start time.Time, reqID string, auth *authContext,
+	model *store.Model, ch *store.Channel, usageInfo *tokenUsage, status, errCode string) {
+
+	latency := int(time.Since(start).Milliseconds())
+	if usageInfo == nil {
+		usageInfo = &tokenUsage{}
+	}
+	cost := billing.CostFromPrices(usageInfo.input, usageInfo.output, usageInfo.cacheRead,
+		billing.PriceSnapshot{
+			InputPrice: model.InputPrice, OutputPrice: model.OutputPrice, CacheReadPrice: model.CacheReadPrice,
+		})
+
+	go func() {
+		// Asynchronous: deduct balance first, then record usage.
+		if cost.IsPositive() {
+			if _, err := g.billing.Deduct(auth.user.ID, cost, "usage", reqID); err != nil {
+				g.log.Warn("deduct balance failed", zap.Error(err),
+					zap.Int64("user_id", auth.user.ID), zap.String("request_id", reqID))
+			}
+		}
+		g.usage.Record(usage.Record{
+			RequestID:           reqID,
+			UserID:              auth.user.ID,
+			KeyID:               auth.key.ID,
+			ChannelID:           ch.ID,
+			ModelID:             model.ID,
+			ModelName:           model.Name,
+			InputTokens:         usageInfo.input,
+			OutputTokens:        usageInfo.output,
+			CacheReadTokens:     usageInfo.cacheRead,
+			CacheCreationTokens: usageInfo.cacheCreation,
+			InputPrice:          model.InputPrice,
+			OutputPrice:         model.OutputPrice,
+			CacheReadPrice:      model.CacheReadPrice,
+			Cost:                cost,
+			LatencyMs:           latency,
+			Status:              status,
+			ErrorCode:           errCode,
+		})
+		g.db.Model(&store.ApiKey{}).Where("id = ?", auth.key.ID).
+			Update("last_used_at", time.Now())
+	}()
+}
+
+func (g *Gateway) recordError(reqID string, auth *authContext, model *store.Model, ch *store.Channel, start time.Time, errCode string) {
+	g.afterComplete(start, reqID, auth, model, ch, &tokenUsage{}, "error", errCode)
+}
+
+func (g *Gateway) recordCanceled(reqID string, auth *authContext, model *store.Model, ch *store.Channel, start time.Time) {
+	g.afterComplete(start, reqID, auth, model, ch, &tokenUsage{}, "canceled", "client_disconnect")
+}

server/internal/proxy/helpers.go

@@ -0,0 +1,248 @@
+package proxy
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"openteam/server/internal/pkg/crypto"
+	"openteam/server/internal/store"
+)
+
+// tokenUsage is the normalized usage extracted from any protocol.
+type tokenUsage struct {
+	input           int64
+	output          int64
+	cacheRead       int64
+	cacheCreation   int64
+}
+
+// respStreamEvent is the streaming shape of the OpenAI Responses API used for
+// usage sniffing on passthrough responses streams.
+type respStreamEvent struct {
+	Type     string `json:"type"`
+	Response *struct {
+		Usage *struct {
+			InputTokens  int64 `json:"input_tokens"`
+			OutputTokens int64 `json:"output_tokens"`
+		} `json:"usage"`
+	} `json:"response"`
+}
+
+// authenticate resolves the Bearer API key to a key + user.
+func (g *Gateway) authenticate(c *gin.Context) (*authContext, error) {
+	auth := c.GetHeader("Authorization")
+	token := ""
+	if strings.HasPrefix(auth, "Bearer ") {
+		token = strings.TrimPrefix(auth, "Bearer ")
+	} else if strings.HasPrefix(auth, "sk-") {
+		// Some clients send the raw key without the Bearer scheme.
+		token = auth
+	} else {
+		return nil, errUnauthorized
+	}
+
+	var key store.ApiKey
+	if err := g.db.Where("key_hash = ?", crypto.HashSHA256(token)).First(&key).Error; err != nil {
+		return nil, errUnauthorized
+	}
+	if key.Status != "active" {
+		return nil, errUnauthorized
+	}
+	if key.ExpiresAt != nil && key.ExpiresAt.Before(now()) {
+		return nil, errUnauthorized
+	}
+	var user store.User
+	if err := g.db.First(&user, key.UserID).Error; err != nil {
+		return nil, errUnauthorized
+	}
+	if user.Status != "active" {
+		return nil, errUnauthorized
+	}
+	return &authContext{key: &key, user: &user}, nil
+}
+
+var errUnauthorized = &unauthorizedError{}
+
+type unauthorizedError struct{}
+
+func (*unauthorizedError) Error() string { return "invalid API key" }
+
+// writeProxyError writes a gateway-generated error in the client's protocol.
+func (g *Gateway) writeProxyError(c *gin.Context, proto Protocol, status int, message string) {
+	c.Header("Content-Type", "application/json")
+	switch proto {
+	case ProtocolAnthropic:
+		c.AbortWithStatusJSON(status, map[string]any{
+			"type": "error",
+			"error": map[string]any{"type": statusType(status), "message": message},
+		})
+	default:
+		c.AbortWithStatusJSON(status, map[string]any{
+			"error": map[string]any{"message": message, "type": "gateway_error", "code": "gateway_error"},
+		})
+	}
+}
+
+// writeUpstreamError maps an upstream error body to the client protocol.
+func (g *Gateway) writeUpstreamError(c *gin.Context, proto Protocol, status int, body []byte) {
+	switch proto {
+	case ProtocolAnthropic:
+		// Extract the upstream Claude error if present.
+		var up struct {
+			Error struct {
+				Type    string `json:"type"`
+				Message string `json:"message"`
+			} `json:"error"`
+		}
+		if json.Unmarshal(body, &up) == nil && up.Error.Message != "" {
+			c.AbortWithStatusJSON(status, map[string]any{
+				"type":  "error",
+				"error": map[string]any{"type": up.Error.Type, "message": up.Error.Message},
+			})
+			return
+		}
+		c.AbortWithStatusJSON(status, map[string]any{
+			"type":  "error",
+			"error": map[string]any{"type": statusType(status), "message": upstreamMessage(status, body)},
+		})
+	default:
+		var up struct {
+			Error struct {
+				Message string `json:"message"`
+				Type    string `json:"type"`
+				Code    string `json:"code"`
+				Param   string `json:"param"`
+			} `json:"error"`
+		}
+		if json.Unmarshal(body, &up) == nil && up.Error.Message != "" {
+			c.AbortWithStatusJSON(status, map[string]any{
+				"error": map[string]any{
+					"message": up.Error.Message, "type": up.Error.Type, "code": up.Error.Code, "param": up.Error.Param,
+				},
+			})
+			return
+		}
+		c.AbortWithStatusJSON(status, map[string]any{
+			"error": map[string]any{
+				"message": upstreamMessage(status, body), "type": statusType(status), "code": statusType(status),
+			},
+		})
+	}
+}
+
+func statusType(status int) string {
+	switch {
+	case status == 429:
+		return "rate_limit_error"
+	case status >= 500:
+		return "api_error"
+	case status >= 400:
+		return "invalid_request_error"
+	default:
+		return "api_error"
+	}
+}
+
+func upstreamMessage(status int, body []byte) string {
+	msg := strings.TrimSpace(string(body))
+	if msg == "" {
+		msg = http.StatusText(status)
+	}
+	return truncateText(msg, 512)
+}
+
+func truncateText(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n] + "..."
+}
+
+// copyProxyHeaders forwards selected request headers upstream.
+func copyProxyHeaders(c *gin.Context, req *http.Request) {
+	for _, h := range []string{"OpenAI-Organization", "OpenAI-Beta", "anthropic-version", "anthropic-beta", "X-Stainless-Lang", "X-Stainless-Package-Version"} {
+		if v := c.GetHeader(h); v != "" {
+			req.Header.Set(h, v)
+		}
+	}
+}
+
+// bodyStreamFlag determines streaming intent from the raw body + route.
+func bodyStreamFlag(body []byte, route Route) bool {
+	var m struct {
+		Stream bool `json:"stream"`
+	}
+	_ = json.Unmarshal(body, &m)
+	return m.Stream
+}
+
+// setModelField rewrites the "model" key in a JSON object.
+func setModelField(body []byte, model string) ([]byte, error) {
+	var obj map[string]json.RawMessage
+	if err := json.Unmarshal(body, &obj); err != nil {
+		return nil, err
+	}
+	m, _ := json.Marshal(model)
+	obj["model"] = m
+	return json.Marshal(obj)
+}
+
+// sameModel reports whether the body's model already equals upstreamModel.
+func sameModel(body []byte, upstreamModel string) bool {
+	var m struct {
+		Model string `json:"model"`
+	}
+	_ = json.Unmarshal(body, &m)
+	return m.Model == upstreamModel
+}
+
+func contains(list []string, s string) bool {
+	for _, v := range list {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}
+
+// upstreamPath returns the endpoint to POST to. When the channel serves the
+// client protocol natively the route's own path is used; otherwise the request
+// is converted and must hit the channel's conversion-target path.
+func upstreamPath(route Route, ch *store.Channel) string {
+	if ch.SupportsFormat(string(route.Protocol)) {
+		return route.UpstreamPath
+	}
+	if ch.Provider == "anthropic" {
+		return "/v1/messages"
+	}
+	return "/v1/chat/completions"
+}
+
+// upstreamProvider returns the format family ("openai" | "anthropic") the
+// channel will actually speak for this request: the client's own family on
+// passthrough, otherwise the channel's conversion target.
+func upstreamProvider(route Route, ch *store.Channel) string {
+	if ch.SupportsFormat(string(route.Protocol)) {
+		return route.NativeProvider
+	}
+	return ch.Provider
+}
+
+// channelServesFormat reports whether the channel can handle the route's
+// protocol: natively, or via a conversion path that exists. Every protocol can
+// convert to either Claude or chat completions except one case: Responses-API
+// requests have no conversion into an openai-family upstream (the
+// responses->chat response side is unimplemented), so an openai-family channel
+// that does not declare responses support cannot serve them at all.
+func channelServesFormat(ch *store.Channel, route Route) bool {
+	if ch.SupportsFormat(string(route.Protocol)) {
+		return true
+	}
+	return !(route.Protocol == ProtocolOpenAIResponses && ch.Provider != "anthropic")
+}
+
+func now() time.Time { return time.Now() }

server/internal/proxy/models.go

@@ -0,0 +1,34 @@
+package proxy
+
+import (
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+)
+
+// ModelsHandler serves GET /v1/models (OpenAI-style list).
+type ModelsHandler struct {
+	db  *gorm.DB
+	gw  *Gateway
+}
+
+func NewModelsHandler(db *gorm.DB, gw *Gateway) *ModelsHandler {
+	return &ModelsHandler{db: db, gw: gw}
+}
+
+func (h *ModelsHandler) List(c *gin.Context) {
+	models, err := h.gw.channel.ListEnabledModels()
+	if err != nil {
+		c.JSON(502, gin.H{"error": gin.H{"message": "list models failed", "type": "api_error"}})
+		return
+	}
+	data := make([]gin.H, 0, len(models))
+	for _, m := range models {
+		data = append(data, gin.H{
+			"id":       m.Name,
+			"object":   "model",
+			"created":  m.CreatedAt.Unix(),
+			"owned_by": "openteam",
+		})
+	}
+	c.JSON(200, gin.H{"object": "list", "data": data})
+}

server/internal/proxy/openai/types.go

@@ -0,0 +1,87 @@
+package openai
+
+import "encoding/json"
+
+// ChatRequest is a chat completions request. Only the fields the gateway
+// needs are typed; the rest is preserved via Raw for passthrough.
+type ChatRequest struct {
+	Model       string          `json:"model"`
+	Messages    json.RawMessage `json:"messages"`
+	Stream      bool            `json:"stream"`
+	Temperature *float64        `json:"temperature"`
+	TopP        *float64        `json:"top_p"`
+	MaxTokens   *int            `json:"max_tokens"`
+	MaxCompl    *int            `json:"max_completion_tokens"`
+	Stop        json.RawMessage `json:"stop"`
+	Tools       json.RawMessage `json:"tools"`
+	ToolChoice  json.RawMessage `json:"tool_choice"`
+	ResponseFmt json.RawMessage `json:"response_format"`
+	StreamOpts  json.RawMessage `json:"stream_options"`
+	User        string          `json:"user"`
+}
+
+// ChatMessage is one message in the canonical/chat shape.
+type ChatMessage struct {
+	Role      string          `json:"role"`
+	Content   json.RawMessage `json:"content,omitempty"`
+	Name      string          `json:"name,omitempty"`
+	ToolCalls json.RawMessage `json:"tool_calls,omitempty"`
+	ToolCallID string         `json:"tool_call_id,omitempty"`
+}
+
+// Tool is a function tool definition.
+type Tool struct {
+	Type     string          `json:"type"`
+	Function FunctionTool    `json:"function"`
+}
+
+type FunctionTool struct {
+	Name        string          `json:"name"`
+	Description string          `json:"description"`
+	Parameters  json.RawMessage `json:"parameters"`
+}
+
+// ChatCompletion is the non-stream response.
+type ChatCompletion struct {
+	ID      string          `json:"id"`
+	Object  string          `json:"object"`
+	Created int64           `json:"created"`
+	Model   string          `json:"model"`
+	Choices []ChatChoice    `json:"choices"`
+	Usage   *Usage          `json:"usage,omitempty"`
+}
+
+type ChatChoice struct {
+	Index        int          `json:"index"`
+	Message      ChatMessage  `json:"message"`
+	FinishReason string       `json:"finish_reason"`
+}
+
+// Usage is the token usage block.
+type Usage struct {
+	PromptTokens     int64 `json:"prompt_tokens"`
+	CompletionTokens int64 `json:"completion_tokens"`
+	TotalTokens      int64 `json:"total_tokens"`
+}
+
+// ChatChunk is one streaming chunk.
+type ChatChunk struct {
+	ID      string        `json:"id"`
+	Object  string        `json:"object"`
+	Created int64         `json:"created"`
+	Model   string        `json:"model"`
+	Choices []ChatChunkChoice `json:"choices"`
+	Usage   *Usage        `json:"usage,omitempty"`
+}
+
+type ChatChunkChoice struct {
+	Index        int           `json:"index"`
+	Delta        ChatDelta     `json:"delta"`
+	FinishReason *string       `json:"finish_reason"`
+}
+
+type ChatDelta struct {
+	Role      string          `json:"role,omitempty"`
+	Content   string          `json:"content,omitempty"`
+	ToolCalls json.RawMessage `json:"tool_calls,omitempty"`
+}

server/internal/proxy/responses/types.go

@@ -0,0 +1,42 @@
+package responses
+
+import "encoding/json"
+
+// Request is an OpenAI Responses API request. The gateway only needs the
+// model + stream fields for routing; the full body passes through raw.
+type Request struct {
+	Model           string          `json:"model"`
+	Stream          bool            `json:"stream"`
+	Instructions    json.RawMessage `json:"instructions"`
+	Input           json.RawMessage `json:"input"`
+	MaxOutputTokens *int            `json:"max_output_tokens"`
+	PreviousResponseID string       `json:"previous_response_id"`
+	Tools           json.RawMessage `json:"tools"`
+	Reasoning       json.RawMessage `json:"reasoning"`
+	Text            json.RawMessage `json:"text"`
+	OutputFormat    json.RawMessage `json:"output_format"`
+}
+
+// Response is the non-stream Responses response.
+type Response struct {
+	ID       string       `json:"id"`
+	Object   string       `json:"object"`
+	Created  int64        `json:"created"`
+	Model    string       `json:"model"`
+	Status   string       `json:"status"`
+	Output   json.RawMessage `json:"output"`
+	Usage    *Usage       `json:"usage,omitempty"`
+}
+
+type Usage struct {
+	InputTokens          int64 `json:"input_tokens"`
+	OutputTokens         int64 `json:"output_tokens"`
+	TotalTokens          int64 `json:"total_tokens"`
+	InputTokensDetails   UsageDetails `json:"input_tokens_details,omitempty"`
+	OutputTokensDetails  UsageDetails `json:"output_tokens_details,omitempty"`
+}
+
+type UsageDetails struct {
+	CachedTokens int64 `json:"cached_tokens,omitempty"`
+	ReasoningTokens int64 `json:"reasoning_tokens,omitempty"`
+}

server/internal/proxy/stream.go

@@ -0,0 +1,201 @@
+package proxy
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+
+	"openteam/server/internal/proxy/claude"
+	"openteam/server/internal/proxy/convert"
+	"openteam/server/internal/proxy/openai"
+	"openteam/server/internal/proxy/stream"
+	"openteam/server/internal/store"
+)
+
+// streamOpenAI forwards an SSE stream to an OpenAI-protocol client.
+func (g *Gateway) streamOpenAI(c *gin.Context, route Route, resp *http.Response,
+	start time.Time, reqID string, auth *authContext, model *store.Model, ch *store.Channel) {
+
+	w := c.Writer
+	tr := convert.NewTranslator(clientProto(route), upstreamProvider(route, ch))
+	done := make(chan struct{})
+
+	if tr == nil {
+		// Passthrough: copy raw frames, sniffing usage from OpenAI chunks
+		// and Responses-API stream events.
+		var usage *tokenUsage
+		onEvent := func(ev stream.SSEEvent) {
+			if ev.Done || ev.Data == "" {
+				return
+			}
+			var chunk openai.ChatChunk
+			if json.Unmarshal([]byte(ev.Data), &chunk) == nil && chunk.Usage != nil {
+				usage = &tokenUsage{
+					input:  chunk.Usage.PromptTokens,
+					output: chunk.Usage.CompletionTokens,
+				}
+				return
+			}
+			var resp respStreamEvent
+			if json.Unmarshal([]byte(ev.Data), &resp) == nil && resp.Response != nil && resp.Response.Usage != nil {
+				usage = &tokenUsage{
+					input:  resp.Response.Usage.InputTokens,
+					output: resp.Response.Usage.OutputTokens,
+				}
+			}
+		}
+		go func() {
+			defer close(done)
+			copyRawSSE(w, resp.Body, onEvent)
+		}()
+		<-done
+		g.afterComplete(start, reqID, auth, model, ch, usage, "success", "")
+		return
+	}
+
+	// Converted: read upstream events, emit translated frames.
+	var finalUsage *tokenUsage
+	go func() {
+		defer close(done)
+		err := stream.ReadSSE(resp.Body, func(ev stream.SSEEvent) error {
+			frames, ferr := tr.Feed(ev)
+			if ferr != nil {
+				return ferr
+			}
+			for _, f := range frames {
+				if err := stream.Write(w, f); err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			g.log.Debug("upstream stream read ended", zap.Error(err))
+		}
+		fin, _ := tr.Finish()
+		for _, f := range fin {
+			_ = stream.Write(w, f)
+		}
+		if u := tr.Usage(); u != nil {
+			finalUsage = &tokenUsage{input: u.Input, output: u.Output, cacheRead: u.CacheRead, cacheCreation: u.CacheCreation}
+		}
+	}()
+	<-done
+	g.afterComplete(start, reqID, auth, model, ch, finalUsage, "success", "")
+}
+
+// streamAnthropic forwards an SSE stream to a Claude-protocol client.
+func (g *Gateway) streamAnthropic(c *gin.Context, route Route, resp *http.Response,
+	start time.Time, reqID string, auth *authContext, model *store.Model, ch *store.Channel) {
+
+	w := c.Writer
+	tr := convert.NewTranslator(clientProto(route), upstreamProvider(route, ch))
+	done := make(chan struct{})
+
+	if tr == nil {
+		// Passthrough: copy raw frames, sniffing usage from message_delta.
+		var usage *tokenUsage
+		onEvent := func(ev stream.SSEEvent) {
+			if ev.Done || ev.Data == "" {
+				return
+			}
+			var e claude.StreamEvent
+			if json.Unmarshal([]byte(ev.Data), &e) != nil || e.Type != "message_delta" {
+				return
+			}
+			var u claude.Usage
+			if json.Unmarshal(e.Usage, &u) == nil {
+				usage = &tokenUsage{
+					input: u.InputTokens, output: u.OutputTokens,
+					cacheRead: u.CacheReadInputTokens, cacheCreation: u.CacheCreationInputTokens,
+				}
+			}
+		}
+		go func() {
+			defer close(done)
+			copyRawSSE(w, resp.Body, onEvent)
+		}()
+		<-done
+		g.afterComplete(start, reqID, auth, model, ch, usage, "success", "")
+		return
+	}
+
+	// Converted: read upstream events, emit translated frames.
+	var finalUsage *tokenUsage
+	go func() {
+		defer close(done)
+		err := stream.ReadSSE(resp.Body, func(ev stream.SSEEvent) error {
+			frames, ferr := tr.Feed(ev)
+			if ferr != nil {
+				return ferr
+			}
+			for _, f := range frames {
+				if err := stream.Write(w, f); err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			g.log.Debug("upstream stream read ended", zap.Error(err))
+		}
+		fin, _ := tr.Finish()
+		for _, f := range fin {
+			_ = stream.Write(w, f)
+		}
+		if u := tr.Usage(); u != nil {
+			finalUsage = &tokenUsage{input: u.Input, output: u.Output, cacheRead: u.CacheRead, cacheCreation: u.CacheCreation}
+		}
+	}()
+	<-done
+	g.afterComplete(start, reqID, auth, model, ch, finalUsage, "success", "")
+}
+
+// copyRawSSE copies an upstream SSE stream verbatim, invoking onEvent for
+// each data frame (used for passthrough + usage sniffing).
+func copyRawSSE(w http.ResponseWriter, r io.Reader, onEvent func(stream.SSEEvent)) {
+	br := bufio.NewReader(r)
+	for {
+		line, err := br.ReadBytes('\n')
+		if len(line) > 0 {
+			if _, werr := w.Write(line); werr != nil {
+				return
+			}
+			trimmed := bytes.TrimSpace(line)
+			if bytes.HasPrefix(trimmed, []byte("data:")) {
+				data := bytes.TrimSpace(trimmed[len("data:"):])
+				ev := stream.SSEEvent{
+					Data: string(data),
+					Done: bytes.Equal(data, []byte("[DONE]")),
+				}
+				if ev.Data != "" {
+					onEvent(ev)
+				}
+			}
+		}
+		if err != nil {
+			break
+		}
+	}
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+}
+
+// clientProto maps a proxy Protocol to the convert package's protocol type.
+func clientProto(route Route) convert.ClientProtocol {
+	switch route.Protocol {
+	case ProtocolOpenAIResponses:
+		return convert.ClientOpenAIResponses
+	case ProtocolAnthropic:
+		return convert.ClientAnthropic
+	default:
+		return convert.ClientOpenAIChat
+	}
+}

server/internal/proxy/stream/stream.go

@@ -0,0 +1,79 @@
+package stream
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"net/http"
+	"strings"
+)
+
+// SSEEvent is a single SSE data frame.
+type SSEEvent struct {
+	Data string // the JSON payload of the `data:` line
+	Done bool   // true when the payload is [DONE]
+}
+
+// ReadSSE reads SSE frames from r, calling fn for each `data:` line.
+// It is used both for reading upstream streams and, via a pipe, for writing
+// converted streams to the client.
+func ReadSSE(r io.Reader, fn func(SSEEvent) error) error {
+	br := bufio.NewReader(r)
+	for {
+		line, err := br.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+		line = trimCRLF(line)
+		if !bytes.HasPrefix([]byte(line), []byte("data:")) {
+			continue
+		}
+		data := line[len("data:"):]
+		data = strings.TrimPrefix(data, " ")
+		if len(data) == 0 {
+			continue
+		}
+		ev := SSEEvent{Data: data, Done: bytes.Equal([]byte(data), []byte("[DONE]"))}
+		if err := fn(ev); err != nil {
+			return err
+		}
+	}
+}
+
+// Write writes an SSE event to w and flushes it.
+func Write(w http.ResponseWriter, ev SSEEvent) error {
+	if ev.Done {
+		if _, err := io.WriteString(w, "data: [DONE]\n\n"); err != nil {
+			return err
+		}
+	} else {
+		if _, err := io.WriteString(w, "data: "+ev.Data+"\n\n"); err != nil {
+			return err
+		}
+	}
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+	return nil
+}
+
+// WriteRaw writes a raw SSE frame string (with trailing newlines) and flushes.
+func WriteRaw(w http.ResponseWriter, frame []byte) error {
+	if _, err := w.Write(frame); err != nil {
+		return err
+	}
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+	return nil
+}
+
+func trimCRLF(s string) string {
+	for len(s) > 0 && (s[len(s)-1] == '\n' || s[len(s)-1] == '\r') {
+		s = s[:len(s)-1]
+	}
+	return s
+}

server/internal/proxy/usage.go

@@ -0,0 +1,48 @@
+package proxy
+
+import (
+	"encoding/json"
+
+	"openteam/server/internal/proxy/claude"
+	"openteam/server/internal/proxy/openai"
+	"openteam/server/internal/proxy/responses"
+)
+
+// parseUsageForProtocol extracts token usage from a non-stream response body.
+func parseUsageForProtocol(proto Protocol, body []byte) *tokenUsage {
+	switch proto {
+	case ProtocolAnthropic:
+		var mr claude.MessageResponse
+		if err := json.Unmarshal(body, &mr); err != nil || mr.Usage == nil {
+			return nil
+		}
+		return &tokenUsage{
+			input:         mr.Usage.InputTokens,
+			output:        mr.Usage.OutputTokens,
+			cacheRead:     mr.Usage.CacheReadInputTokens,
+			cacheCreation: mr.Usage.CacheCreationInputTokens,
+		}
+	case ProtocolOpenAIResponses:
+		var r responses.Response
+		if err := json.Unmarshal(body, &r); err != nil || r.Usage == nil {
+			return nil
+		}
+		return &tokenUsage{
+			input:     r.Usage.InputTokens,
+			output:    r.Usage.OutputTokens,
+			cacheRead: r.Usage.InputTokensDetails.CachedTokens,
+		}
+	default:
+		var cc openai.ChatCompletion
+		if err := json.Unmarshal(body, &cc); err != nil || cc.Usage == nil {
+			return nil
+		}
+		return &tokenUsage{input: cc.Usage.PromptTokens, output: cc.Usage.CompletionTokens}
+	}
+}
+
+// estimateTokensFromText is a coarse fallback used when the upstream omits usage.
+func estimateTokensFromText(s string) int64 {
+	// ~4 chars per token, per OpenAI's common heuristic.
+	return int64(len(s)/4 + 1)
+}

server/internal/recharge/handler.go

@@ -0,0 +1,84 @@
+package recharge
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+	"openteam/server/internal/user"
+)
+
+// Handler exposes the reserved recharge order endpoints.
+type Handler struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewHandler(db *gorm.DB, log *zap.Logger) *Handler {
+	return &Handler{db: db, log: log}
+}
+
+type CreateInput struct {
+	Amount decimal.Decimal `json:"amount" binding:"required"`
+	Remark string          `json:"remark"`
+}
+
+// Create handles POST /api/v1/recharges — creates a pending manual order.
+func (h *Handler) Create(c *gin.Context) {
+	u := user.Current(c)
+	var in CreateInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	if in.Amount.LessThanOrEqual(decimal.Zero) {
+		httpx.Fail(c, http.StatusBadRequest, "amount must be positive")
+		return
+	}
+	order := &store.RechargeOrder{
+		UserID: u.ID,
+		Amount: in.Amount,
+		Status: "pending",
+		Method: "manual",
+		Remark: in.Remark,
+	}
+	if err := h.db.Create(order).Error; err != nil {
+		h.log.Warn("create recharge order failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "create order failed")
+		return
+	}
+	httpx.Created(c, orderDTO(order))
+}
+
+// List handles GET /api/v1/recharges.
+func (h *Handler) List(c *gin.Context) {
+	u := user.Current(c)
+	var orders []store.RechargeOrder
+	if err := h.db.Where("user_id = ?", u.ID).Order("id DESC").Find(&orders).Error; err != nil {
+		h.log.Warn("list recharge orders failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "list orders failed")
+		return
+	}
+	out := make([]gin.H, 0, len(orders))
+	for i := range orders {
+		out = append(out, orderDTO(&orders[i]))
+	}
+	httpx.OK(c, out)
+}
+
+func orderDTO(o *store.RechargeOrder) gin.H {
+	return gin.H{
+		"id":          o.ID,
+		"amount":      o.Amount.String(),
+		"status":      o.Status,
+		"method":      o.Method,
+		"remark":      o.Remark,
+		"reviewedBy":  o.ReviewedBy,
+		"reviewedAt":  o.ReviewedAt,
+		"createdAt":   o.CreatedAt,
+	}
+}

server/internal/store/model.go

@@ -0,0 +1,196 @@
+package store
+
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+	"gorm.io/gorm"
+)
+
+// User is a registered account.
+type User struct {
+	ID           int64  `gorm:"primaryKey"`
+	Username     string `gorm:"uniqueIndex;size:64"`
+	Email        string `gorm:"uniqueIndex;size:255"`
+	PasswordHash string `gorm:"size:255"`
+	Role         string `gorm:"size:16;default:user"` // admin | user
+	Balance      decimal.Decimal `gorm:"type:numeric(20,8);default:0"`
+	Status       string `gorm:"size:16;default:active"` // active | disabled
+	InviteCode   string `gorm:"size:64"`
+	LastLoginAt  *time.Time
+	CreatedAt    time.Time
+	UpdatedAt    time.Time
+}
+
+// ApiKey is an API key issued to a user.
+type ApiKey struct {
+	ID                    int64  `gorm:"primaryKey"`
+	UserID                int64  `gorm:"index"`
+	Name                  string `gorm:"size:128"`
+	KeyHash               string `gorm:"uniqueIndex;size:128"`
+	KeyPrefix             string `gorm:"size:16"`
+	QuotaTokensPerDay     *int64
+	QuotaRequestsPerDay   *int
+	AllowedModels         []string `gorm:"serializer:json"`
+	ExpiresAt             *time.Time
+	Status                string `gorm:"size:16;default:active"` // active | revoked
+	LastUsedAt            *time.Time
+	CreatedAt             time.Time
+	UpdatedAt             time.Time
+}
+
+// Channel is an upstream provider.
+type Channel struct {
+	ID              int64  `gorm:"primaryKey"`
+	Name            string `gorm:"size:128"`
+	Provider        string `gorm:"size:32"` // openai | anthropic | compatible
+	BaseURL         string `gorm:"size:512"`
+	APIKeyEnc       string `gorm:"size:2048"` // AES-GCM ciphertext
+	Weight          int    `gorm:"default:1"`
+	Priority        int    `gorm:"default:0"` // lower = preferred
+	TimeoutMs       int    `gorm:"default:300000"`
+	MaxConcurrency  int    `gorm:"default:100"`
+	HealthStatus    string `gorm:"size:16;default:healthy"` // healthy | degraded | cooldown
+	HealthFailures  int
+	Enabled         bool     `gorm:"default:true"`
+	Formats         []string `gorm:"serializer:json"` // client API formats served natively; empty = derive from Provider
+	CreatedAt       time.Time
+	UpdatedAt       time.Time
+}
+
+// Client API format keys a channel can serve natively. They match the proxy
+// route protocol values so SupportsFormat can compare them directly.
+const (
+	FormatOpenAIChat      = "openai-chat"
+	FormatOpenAIResponses = "openai-responses"
+	FormatAnthropic       = "anthropic"
+)
+
+// FormatsResolved returns the API formats the channel serves directly. When
+// Formats is empty it falls back to the provider's native formats so legacy
+// rows behave exactly as before.
+func (c *Channel) FormatsResolved() []string {
+	if len(c.Formats) > 0 {
+		out := make([]string, len(c.Formats))
+		copy(out, c.Formats)
+		return out
+	}
+	if c.Provider == "anthropic" {
+		return []string{FormatAnthropic}
+	}
+	return []string{FormatOpenAIChat, FormatOpenAIResponses}
+}
+
+// SupportsFormat reports whether the channel serves a client protocol
+// natively (passthrough) without conversion.
+func (c *Channel) SupportsFormat(f string) bool {
+	for _, x := range c.FormatsResolved() {
+		if x == f {
+			return true
+		}
+	}
+	return false
+}
+
+// Model is the global model registry with pricing.
+type Model struct {
+	ID              int64  `gorm:"primaryKey"`
+	Name            string `gorm:"uniqueIndex;size:128"`
+	DisplayName     string `gorm:"size:255"`
+	InputPrice      decimal.Decimal `gorm:"type:numeric(20,8);default:0"` // per 1M tokens
+	OutputPrice     decimal.Decimal `gorm:"type:numeric(20,8);default:0"`
+	CacheReadPrice  decimal.Decimal `gorm:"type:numeric(20,8);default:0"`
+	Enabled         bool   `gorm:"default:true"`
+	Sort            int    `gorm:"default:0"`
+	CreatedAt       time.Time
+	UpdatedAt       time.Time
+}
+
+// ChannelModelBinding binds a global model to a channel with an upstream name.
+type ChannelModelBinding struct {
+	ID            int64 `gorm:"primaryKey"`
+	ChannelID     int64 `gorm:"index;uniqueIndex:idx_channel_model"`
+	ModelID       int64 `gorm:"index;uniqueIndex:idx_channel_model"`
+	UpstreamModel string `gorm:"size:255"`
+	Weight        int    `gorm:"default:1"`
+	Channel       Channel `gorm:"foreignKey:ChannelID"`
+	Model         Model   `gorm:"foreignKey:ModelID"`
+}
+
+// UsageLog is one proxied request's billing record.
+type UsageLog struct {
+	ID                  int64  `gorm:"primaryKey"`
+	RequestID           string `gorm:"size:128"`
+	UserID              int64  `gorm:"index:idx_user_created,priority:1"`
+	KeyID               int64
+	ChannelID           int64
+	ModelID             int64
+	ModelName           string `gorm:"size:128"`
+	InputTokens         int64
+	OutputTokens        int64
+	CacheReadTokens     int64
+	CacheCreationTokens int64
+	InputPrice          decimal.Decimal `gorm:"type:numeric(20,8)"`
+	OutputPrice         decimal.Decimal `gorm:"type:numeric(20,8)"`
+	CacheReadPrice      decimal.Decimal `gorm:"type:numeric(20,8)"`
+	Cost                decimal.Decimal `gorm:"type:numeric(20,8)"`
+	LatencyMs           int
+	Status              string `gorm:"size:16"` // success | error | canceled
+	ErrorCode           string `gorm:"size:64"`
+	CreatedAt           time.Time `gorm:"index:idx_user_created,priority:2"`
+}
+
+// UsageDaily is the pre-aggregated per-user per-model daily rollup.
+type UsageDaily struct {
+	ID                 int64  `gorm:"primaryKey"`
+	UserID             int64  `gorm:"index:idx_user_date,priority:1"`
+	ModelID            int64
+	Date               string `gorm:"size:10;index:idx_user_date,priority:2"` // YYYY-MM-DD
+	Requests           int
+	InputTokens        int64
+	OutputTokens       int64
+	CacheReadTokens    int64
+	CacheCreationTokens int64
+	Cost               decimal.Decimal `gorm:"type:numeric(20,8)"`
+}
+
+// RechargeOrder is reserved for the (paused) recharge feature.
+type RechargeOrder struct {
+	ID            int64 `gorm:"primaryKey"`
+	UserID        int64 `gorm:"index"`
+	Amount        decimal.Decimal `gorm:"type:numeric(20,8)"`
+	Status        string `gorm:"size:16;default:pending"` // pending | credited | rejected
+	Method        string `gorm:"size:16;default:manual"`  // manual | online
+	TransactionID string `gorm:"size:128"`
+	ReviewedBy    *int64
+	ReviewedAt    *time.Time
+	Remark        string `gorm:"size:512"`
+	CreatedAt     time.Time
+	UpdatedAt     time.Time
+	User          User `gorm:"foreignKey:UserID"`
+}
+
+// BalanceLog is a user balance ledger entry.
+type BalanceLog struct {
+	ID           int64 `gorm:"primaryKey"`
+	UserID       int64 `gorm:"index:idx_balance_user_created,priority:1"`
+	Change       decimal.Decimal `gorm:"type:numeric(20,8)"`
+	BalanceAfter decimal.Decimal `gorm:"type:numeric(20,8)"`
+	Type         string `gorm:"size:32"` // recharge | usage | refund | admin_adjust
+	RefID        string `gorm:"size:128"`
+	CreatedAt    time.Time `gorm:"index:idx_balance_user_created,priority:2"`
+}
+
+// SystemConfig is a key/value store for runtime settings.
+type SystemConfig struct {
+	Key   string `gorm:"primaryKey;size:128"`
+	Value []byte `gorm:"serializer:json"`
+}
+
+// Migrate creates/upgrades the schema.
+func Migrate(db *gorm.DB) error {
+	return db.AutoMigrate(
+		&User{}, &ApiKey{}, &Channel{}, &Model{}, &ChannelModelBinding{},
+		&UsageLog{}, &UsageDaily{}, &RechargeOrder{}, &BalanceLog{}, &SystemConfig{},
+	)
+}

server/internal/store/store.go

@@ -0,0 +1,44 @@
+package store
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/glebarez/sqlite"
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+func Open(driver, dsn string, debug bool) (*gorm.DB, error) {
+	cfg := &gorm.Config{}
+	if debug {
+		cfg.Logger = logger.Default.LogMode(logger.Info)
+	} else {
+		cfg.Logger = logger.Default.LogMode(logger.Warn)
+	}
+
+	var dialector gorm.Dialector
+	switch driver {
+	case "postgres":
+		dialector = postgres.Open(dsn)
+	default:
+		if err := os.MkdirAll(filepath.Dir(dsn), 0o755); err != nil {
+			return nil, fmt.Errorf("create data dir: %w", err)
+		}
+		dialector = sqlite.Open(dsn)
+	}
+
+	db, err := gorm.Open(dialector, cfg)
+	if err != nil {
+		return nil, err
+	}
+	sqlDB, err := db.DB()
+	if err != nil {
+		return nil, err
+	}
+	sqlDB.SetMaxOpenConns(20)
+	sqlDB.SetMaxIdleConns(5)
+	return db, nil
+}

server/internal/usage/handler.go

@@ -0,0 +1,193 @@
+package usage
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/store"
+	"openteam/server/internal/user"
+)
+
+type Handler struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewHandler(db *gorm.DB, log *zap.Logger) *Handler {
+	return &Handler{db: db, log: log}
+}
+
+// Summary handles GET /api/v1/usage/summary.
+func (h *Handler) Summary(c *gin.Context) {
+	u := user.Current(c)
+	now := time.Now()
+	today := now.Format("2006-01-02")
+	month := now.Format("2006-01")
+
+	type agg struct {
+		Requests    int
+		InputTokens int64
+		OutputTokens int64
+		Cost        decimal.Decimal
+	}
+
+	todayAgg := h.aggregate(u.ID, today, today)
+	monthAgg := h.aggregate(u.ID, month+"-01", now.Format("2006-01-02"))
+	total := h.aggregate(u.ID, "", "")
+
+	httpx.OK(c, gin.H{
+		"today": gin.H{
+			"requests":     todayAgg.Requests,
+			"inputTokens":  todayAgg.InputTokens,
+			"outputTokens": todayAgg.OutputTokens,
+			"cost":         todayAgg.Cost.String(),
+		},
+		"month": gin.H{
+			"requests":     monthAgg.Requests,
+			"inputTokens":  monthAgg.InputTokens,
+			"outputTokens": monthAgg.OutputTokens,
+			"cost":         monthAgg.Cost.String(),
+		},
+		"total": gin.H{
+			"requests":     total.Requests,
+			"inputTokens":  total.InputTokens,
+			"outputTokens": total.OutputTokens,
+			"cost":         total.Cost.String(),
+		},
+	})
+}
+
+func (h *Handler) aggregate(userID int64, from, to string) struct {
+	Requests    int
+	InputTokens int64
+	OutputTokens int64
+	Cost        decimal.Decimal
+} {
+	var out struct {
+		Requests    int
+		InputTokens int64
+		OutputTokens int64
+		Cost        decimal.Decimal
+	}
+	q := h.db.Model(&store.UsageDaily{}).Where("user_id = ?", userID)
+	if from != "" {
+		q = q.Where("date >= ?", from)
+	}
+	if to != "" {
+		q = q.Where("date <= ?", to)
+	}
+	q.Select("COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+		Scan(&out)
+	return out
+}
+
+// Stats handles GET /api/v1/usage/stats?from&to&group=day|model.
+func (h *Handler) Stats(c *gin.Context) {
+	u := user.Current(c)
+	from := c.Query("from")
+	to := c.Query("to")
+	group := c.DefaultQuery("group", "day")
+
+	var rows []struct {
+		Key          string `gorm:"column:g"`
+		Requests     int
+		InputTokens  int64
+		OutputTokens int64
+		Cost         decimal.Decimal
+	}
+
+	q := h.db.Model(&store.UsageDaily{}).Where("user_id = ?", u.ID)
+	if from != "" {
+		q = q.Where("date >= ?", from)
+	}
+	if to != "" {
+		q = q.Where("date <= ?", to)
+	}
+
+	switch group {
+	case "model":
+		q = q.Joins("JOIN models ON models.id = usage_dailies.model_id").
+			Select("models.name as g, COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+			Group("models.name")
+	default:
+		q = q.Select("date as g, COALESCE(SUM(requests),0) as requests, COALESCE(SUM(input_tokens),0) as input_tokens, COALESCE(SUM(output_tokens),0) as output_tokens, COALESCE(SUM(cost),0) as cost").
+			Group("date").Order("date ASC")
+	}
+	if err := q.Scan(&rows).Error; err != nil {
+		h.log.Warn("usage stats failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "usage stats failed")
+		return
+	}
+	out := make([]gin.H, 0, len(rows))
+	for _, r := range rows {
+		out = append(out, gin.H{
+			"key":          r.Key,
+			"requests":     r.Requests,
+			"inputTokens":  r.InputTokens,
+			"outputTokens": r.OutputTokens,
+			"cost":         r.Cost.String(),
+		})
+	}
+	httpx.OK(c, out)
+}
+
+// Logs handles GET /api/v1/usage/logs?from&to&page&model&keyId.
+func (h *Handler) Logs(c *gin.Context) {
+	u := user.Current(c)
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	pageSize := 20
+	if page < 1 {
+		page = 1
+	}
+	from := c.Query("from")
+	to := c.Query("to")
+
+	q := h.db.Model(&store.UsageLog{}).Where("user_id = ?", u.ID)
+	if from != "" {
+		q = q.Where("created_at >= ?", from)
+	}
+	if to != "" {
+		q = q.Where("created_at <= ?", to+" 23:59:59")
+	}
+	if m := c.Query("model"); m != "" {
+		q = q.Where("model_name = ?", m)
+	}
+	if kid := c.Query("keyId"); kid != "" {
+		q = q.Where("key_id = ?", kid)
+	}
+
+	var total int64
+	q.Count(&total)
+
+	var logs []store.UsageLog
+	if err := q.Order("id DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&logs).Error; err != nil {
+		h.log.Warn("usage logs failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "usage logs failed")
+		return
+	}
+	out := make([]gin.H, 0, len(logs))
+	for _, l := range logs {
+		out = append(out, gin.H{
+			"id":               l.ID,
+			"requestId":        l.RequestID,
+			"model":            l.ModelName,
+			"channelId":        l.ChannelID,
+			"inputTokens":      l.InputTokens,
+			"outputTokens":     l.OutputTokens,
+			"cacheReadTokens":  l.CacheReadTokens,
+			"cost":             l.Cost.String(),
+			"latencyMs":        l.LatencyMs,
+			"status":           l.Status,
+			"errorCode":        l.ErrorCode,
+			"createdAt":        l.CreatedAt,
+		})
+	}
+	httpx.OK(c, gin.H{"total": total, "page": page, "pageSize": pageSize, "items": out})
+}

server/internal/usage/service.go

@@ -0,0 +1,91 @@
+package usage
+
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+
+	"openteam/server/internal/store"
+)
+
+type Record struct {
+	RequestID           string
+	UserID              int64
+	KeyID               int64
+	ChannelID           int64
+	ModelID             int64
+	ModelName           string
+	InputTokens         int64
+	OutputTokens        int64
+	CacheReadTokens     int64
+	CacheCreationTokens int64
+	InputPrice          decimal.Decimal
+	OutputPrice         decimal.Decimal
+	CacheReadPrice      decimal.Decimal
+	Cost                decimal.Decimal
+	LatencyMs           int
+	Status              string
+	ErrorCode           string
+}
+
+type Service struct {
+	db  *gorm.DB
+	log *zap.Logger
+}
+
+func NewService(db *gorm.DB, log *zap.Logger) *Service {
+	return &Service{db: db, log: log}
+}
+
+// Record inserts a request-level usage log and upserts the daily aggregate.
+func (s *Service) Record(r Record) error {
+	date := time.Now().Format("2006-01-02")
+	err := s.db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Create(&store.UsageLog{
+			RequestID:           r.RequestID,
+			UserID:              r.UserID,
+			KeyID:               r.KeyID,
+			ChannelID:           r.ChannelID,
+			ModelID:             r.ModelID,
+			ModelName:           r.ModelName,
+			InputTokens:         r.InputTokens,
+			OutputTokens:        r.OutputTokens,
+			CacheReadTokens:     r.CacheReadTokens,
+			CacheCreationTokens: r.CacheCreationTokens,
+			InputPrice:          r.InputPrice,
+			OutputPrice:         r.OutputPrice,
+			CacheReadPrice:      r.CacheReadPrice,
+			Cost:                r.Cost,
+			LatencyMs:           r.LatencyMs,
+			Status:              r.Status,
+			ErrorCode:           r.ErrorCode,
+			CreatedAt:           time.Now(),
+		}).Error; err != nil {
+			return err
+		}
+
+		var daily store.UsageDaily
+		err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
+			Where("user_id = ? AND model_id = ? AND date = ?", r.UserID, r.ModelID, date).
+			FirstOrCreate(&daily, store.UsageDaily{
+				UserID: r.UserID, ModelID: r.ModelID, Date: date,
+			}).Error
+		if err != nil {
+			return err
+		}
+		daily.Requests++
+		daily.InputTokens += r.InputTokens
+		daily.OutputTokens += r.OutputTokens
+		daily.CacheReadTokens += r.CacheReadTokens
+		daily.CacheCreationTokens += r.CacheCreationTokens
+		daily.Cost = daily.Cost.Add(r.Cost)
+		return tx.Save(&daily).Error
+	})
+	if err != nil {
+		s.log.Warn("record usage failed", zap.Error(err))
+	}
+	return err
+}

server/internal/user/handler.go

@@ -0,0 +1,107 @@
+package user
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+
+	"openteam/server/internal/config"
+	"openteam/server/internal/pkg/httpx"
+)
+
+type Handler struct {
+	svc *Service
+	cfg *config.Config
+	log *zap.Logger
+}
+
+func NewHandler(svc *Service, cfg *config.Config, log *zap.Logger) *Handler {
+	return &Handler{svc: svc, cfg: cfg, log: log}
+}
+
+// Register handles POST /api/v1/auth/register.
+func (h *Handler) Register(c *gin.Context) {
+	var in RegisterInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	u, pair, err := h.svc.Register(in)
+	if err != nil {
+		if errors.Is(err, ErrUserExists) {
+			httpx.Fail(c, http.StatusConflict, err.Error())
+			return
+		}
+		h.log.Warn("register failed", zap.Error(err))
+		httpx.Fail(c, http.StatusBadRequest, err.Error())
+		return
+	}
+	h.setRefreshCookie(c, pair.RefreshToken)
+	httpx.Created(c, gin.H{"user": GetPublic(u), "token": pair})
+}
+
+// Login handles POST /api/v1/auth/login.
+func (h *Handler) Login(c *gin.Context) {
+	var in LoginInput
+	if !httpx.Bind(c, &in) {
+		return
+	}
+	u, pair, err := h.svc.Login(in)
+	if err != nil {
+		if errors.Is(err, ErrBadCredentials) || errors.Is(err, ErrUserDisabled) {
+			httpx.Fail(c, http.StatusUnauthorized, err.Error())
+			return
+		}
+		h.log.Warn("login failed", zap.Error(err))
+		httpx.Fail(c, http.StatusInternalServerError, "login failed")
+		return
+	}
+	h.setRefreshCookie(c, pair.RefreshToken)
+	httpx.OK(c, gin.H{"user": GetPublic(u), "token": pair})
+}
+
+// Refresh handles POST /api/v1/auth/refresh.
+func (h *Handler) Refresh(c *gin.Context) {
+	token, err := c.Cookie(h.cfg.Auth.RefreshCookieName)
+	if err != nil || token == "" {
+		httpx.Fail(c, http.StatusUnauthorized, "missing refresh token")
+		return
+	}
+	pair, err := h.svc.Refresh(token)
+	if err != nil {
+		httpx.Fail(c, http.StatusUnauthorized, "invalid refresh token")
+		return
+	}
+	h.setRefreshCookie(c, pair.RefreshToken)
+	httpx.OK(c, gin.H{"token": pair})
+}
+
+// Logout handles POST /api/v1/auth/logout.
+func (h *Handler) Logout(c *gin.Context) {
+	c.SetCookie(h.cfg.Auth.RefreshCookieName, "", -1, "/", "", h.cfg.Auth.RefreshCookieSecure, true)
+	httpx.OK(c, gin.H{"ok": true})
+}
+
+// Me handles GET /api/v1/auth/me.
+func (h *Handler) Me(c *gin.Context) {
+	u := Current(c)
+	httpx.OK(c, GetPublic(u))
+}
+
+// Profile handles GET /api/v1/user/profile.
+func (h *Handler) Profile(c *gin.Context) {
+	u := Current(c)
+	httpx.OK(c, GetPublic(u))
+}
+
+// Balance handles GET /api/v1/user/balance.
+func (h *Handler) Balance(c *gin.Context) {
+	u := Current(c)
+	httpx.OK(c, gin.H{"balance": u.Balance.String()})
+}
+
+func (h *Handler) setRefreshCookie(c *gin.Context, token string) {
+	c.SetCookie(h.cfg.Auth.RefreshCookieName, token,
+		int(h.cfg.Auth.RefreshTokenTTL.Seconds()), "/", "", h.cfg.Auth.RefreshCookieSecure, true)
+}

server/internal/user/middleware.go

@@ -0,0 +1,74 @@
+package user
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+
+	"openteam/server/internal/pkg/httpx"
+	"openteam/server/internal/pkg/jwt"
+	"openteam/server/internal/store"
+)
+
+const (
+	ctxUserKey = "current_user"
+	ctxClaimsKey = "current_claims"
+)
+
+// Current returns the authenticated user (set by Middleware).
+func Current(c *gin.Context) *store.User {
+	if v, ok := c.Get(ctxUserKey); ok {
+		if u, ok := v.(*store.User); ok {
+			return u
+		}
+	}
+	return nil
+}
+
+// Claims returns the JWT claims of the current request.
+func Claims(c *gin.Context) *jwt.Claims {
+	if v, ok := c.Get(ctxClaimsKey); ok {
+		if cl, ok := v.(*jwt.Claims); ok {
+			return cl
+		}
+	}
+	return nil
+}
+
+// Middleware authenticates the management API via an access token.
+func (s *Service) Middleware(secret string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		auth := c.GetHeader("Authorization")
+		if !strings.HasPrefix(auth, "Bearer ") {
+			httpx.Fail(c, http.StatusUnauthorized, "missing bearer token")
+			return
+		}
+		token := strings.TrimPrefix(auth, "Bearer ")
+		claims, err := jwt.Parse(secret, token)
+		if err != nil || claims.Type != "access" {
+			httpx.Fail(c, http.StatusUnauthorized, "invalid or expired token")
+			return
+		}
+		var u store.User
+		if err := s.db.First(&u, claims.UserID).Error; err != nil || u.Status != "active" {
+			httpx.Fail(c, http.StatusUnauthorized, "user not found or disabled")
+			return
+		}
+		c.Set(ctxUserKey, &u)
+		c.Set(ctxClaimsKey, claims)
+		c.Next()
+	}
+}
+
+// RequireAdmin guards admin-only routes.
+func RequireAdmin() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		u := Current(c)
+		if u == nil || u.Role != "admin" {
+			httpx.Fail(c, http.StatusForbidden, "admin only")
+			return
+		}
+		c.Next()
+	}
+}

server/internal/user/service.go

@@ -0,0 +1,192 @@
+package user
+
+import (
+	"encoding/json"
+	"errors"
+	"time"
+
+	"github.com/shopspring/decimal"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
+	"openteam/server/internal/config"
+	"openteam/server/internal/pkg/jwt"
+	"openteam/server/internal/pkg/password"
+	"openteam/server/internal/store"
+)
+
+var (
+	ErrUserExists     = errors.New("username or email already exists")
+	ErrBadCredentials = errors.New("invalid username/email or password")
+	ErrUserDisabled   = errors.New("account disabled")
+	ErrInvalidRefresh = errors.New("invalid refresh token")
+)
+
+type Service struct {
+	db  *gorm.DB
+	cfg *config.Config
+	log *zap.Logger
+}
+
+func NewService(db *gorm.DB, cfg *config.Config, log *zap.Logger) *Service {
+	return &Service{db: db, cfg: cfg, log: log}
+}
+
+type RegisterInput struct {
+	Username   string `json:"username" binding:"required,min=3,max=64"`
+	Email      string `json:"email" binding:"required,email"`
+	Password   string `json:"password" binding:"required,min=8,max=128"`
+	InviteCode string `json:"inviteCode"`
+}
+
+type TokenPair struct {
+	AccessToken  string `json:"accessToken"`
+	TokenType    string `json:"tokenType"`
+	ExpiresIn    int64  `json:"expiresIn"`
+	RefreshToken string `json:"refreshToken"`
+}
+
+// Register creates a user. Returns a token pair plus the created user.
+func (s *Service) Register(in RegisterInput) (*store.User, *TokenPair, error) {
+	if s.cfg.Registration.Mode == "invite" {
+		// Invite mode: validate the invite code before allowing signup.
+		ok, err := s.validateInviteCode(in.InviteCode)
+		if err != nil {
+			return nil, nil, err
+		}
+		if !ok {
+			return nil, nil, errors.New("invalid invite code")
+		}
+	}
+
+	hash, err := password.Hash(in.Password)
+	if err != nil {
+		return nil, nil, err
+	}
+	u := &store.User{
+		Username:     in.Username,
+		Email:        in.Email,
+		PasswordHash: hash,
+		Role:         "user",
+		Balance:      decimalZero(),
+		Status:       "active",
+		InviteCode:   in.InviteCode,
+	}
+	if err := s.db.Create(u).Error; err != nil {
+		if errors.Is(err, gorm.ErrDuplicatedKey) {
+			return nil, nil, ErrUserExists
+		}
+		return nil, nil, err
+	}
+	pair, err := s.issuePair(u)
+	if err != nil {
+		return nil, nil, err
+	}
+	return u, pair, nil
+}
+
+type LoginInput struct {
+	Account  string `json:"account" binding:"required"` // username or email
+	Password string `json:"password" binding:"required"`
+}
+
+// Login authenticates by username or email and returns a token pair.
+func (s *Service) Login(in LoginInput) (*store.User, *TokenPair, error) {
+	var u store.User
+	err := s.db.Where("username = ? OR email = ?", in.Account, in.Account).First(&u).Error
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		return nil, nil, ErrBadCredentials
+	}
+	if err != nil {
+		return nil, nil, err
+	}
+	ok, err := password.Verify(in.Password, u.PasswordHash)
+	if err != nil || !ok {
+		return nil, nil, ErrBadCredentials
+	}
+	if u.Status != "active" {
+		return nil, nil, ErrUserDisabled
+	}
+	now := time.Now()
+	u.LastLoginAt = &now
+	s.db.Model(&u).Update("last_login_at", now)
+	pair, err := s.issuePair(&u)
+	if err != nil {
+		return nil, nil, err
+	}
+	return &u, pair, nil
+}
+
+// Refresh issues a new access token from a valid refresh token.
+func (s *Service) Refresh(refreshToken string) (*TokenPair, error) {
+	claims, err := jwt.Parse(s.cfg.Auth.JWTSecret, refreshToken)
+	if err != nil || claims.Type != "refresh" {
+		return nil, ErrInvalidRefresh
+	}
+	var u store.User
+	if err := s.db.First(&u, claims.UserID).Error; err != nil {
+		return nil, ErrInvalidRefresh
+	}
+	if u.Status != "active" {
+		return nil, ErrUserDisabled
+	}
+	return s.issuePair(&u)
+}
+
+// GetByID loads a user.
+func (s *Service) GetByID(id int64) (*store.User, error) {
+	var u store.User
+	if err := s.db.First(&u, id).Error; err != nil {
+		return nil, err
+	}
+	return &u, nil
+}
+
+// GetPublic returns a user DTO without secrets.
+func GetPublic(u *store.User) map[string]any {
+	return map[string]any{
+		"id":         u.ID,
+		"username":   u.Username,
+		"email":      u.Email,
+		"role":       u.Role,
+		"balance":    u.Balance.String(),
+		"status":     u.Status,
+		"createdAt":  u.CreatedAt,
+		"lastLoginAt": u.LastLoginAt,
+	}
+}
+
+func (s *Service) validateInviteCode(code string) (bool, error) {
+	var conf store.SystemConfig
+	if err := s.db.First(&conf, "key = ?", "invite_codes").Error; err != nil {
+		return false, nil
+	}
+	var codes map[string]bool
+	if len(conf.Value) > 0 {
+		if err := json.Unmarshal(conf.Value, &codes); err != nil {
+			return false, err
+		}
+	}
+	return codes[code], nil
+}
+
+func (s *Service) issuePair(u *store.User) (*TokenPair, error) {
+	access, err := jwt.SignAccess(s.cfg.Auth.JWTSecret, u.ID, u.Username, u.Role, s.cfg.Auth.AccessTokenTTL)
+	if err != nil {
+		return nil, err
+	}
+	refresh, err := jwt.SignRefresh(s.cfg.Auth.JWTSecret, u.ID, s.cfg.Auth.RefreshTokenTTL)
+	if err != nil {
+		return nil, err
+	}
+	return &TokenPair{
+		AccessToken: access,
+		TokenType:   "Bearer",
+		ExpiresIn:   int64(s.cfg.Auth.AccessTokenTTL.Seconds()),
+		RefreshToken: refresh,
+	}, nil
+}
+
+func decimalZero() decimal.Decimal {
+	return decimal.NewFromInt(0)
+}