fix: resolve duplicate MCP route registration causing 50% failure rate

Fixes #7772

The issue was caused by duplicate registration of the MCP endpoint
/mcp/v1/chat/completions in both openai.go and localai.go, leading
to a race condition where requests would randomly hit different
handlers with incompatible behaviors.

Changes:
- Removed duplicate MCP route registration from openai.go
- Kept the localai.MCPStreamEndpoint as the canonical handler
- Added all three MCP route patterns for backward compatibility:
  * /v1/mcp/chat/completions
  * /mcp/v1/chat/completions
  * /mcp/chat/completions
- Added comments to clarify route ownership and prevent future conflicts
- Fixed formatting in ui_api.go

The localai.MCPStreamEndpoint handler is more feature-complete as it
supports both streaming and non-streaming modes, while the removed
openai.MCPCompletionEndpoint only supported synchronous requests.

This eliminates the ~50% failure rate where the cogito library would
receive "Invalid http method" errors when internal HTTP requests were
routed to the wrong handler.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Signed-off-by: majiayu000 <1835304752@qq.com>

core/http/routes/localai.go

@@ -137,7 +137,8 @@ func RegisterLocalAIRoutes(router *echo.Echo,
 		requestExtractor.BuildFilteredFirstAvailableDefaultModel(config.BuildUsecaseFilterFn(config.FLAG_TOKENIZE)),
 		requestExtractor.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.TokenizeRequest) }))
 
-	// MCP Stream endpoint
+	// MCP endpoint - supports both streaming and non-streaming modes
+	// Note: These are the canonical MCP routes (not duplicated in openai.go)
 	if evaluator != nil {
 		mcpStreamHandler := localai.MCPStreamEndpoint(cl, ml, evaluator, appConfig)
 		mcpStreamMiddleware := []echo.MiddlewareFunc{
@@ -154,6 +155,7 @@ func RegisterLocalAIRoutes(router *echo.Echo,
 		}
 		router.POST("/v1/mcp/chat/completions", mcpStreamHandler, mcpStreamMiddleware...)
 		router.POST("/mcp/v1/chat/completions", mcpStreamHandler, mcpStreamMiddleware...)
+		router.POST("/mcp/chat/completions", mcpStreamHandler, mcpStreamMiddleware...)
 	}
 
 	// Agent job routes

core/http/routes/openai.go

@@ -79,23 +79,8 @@ func RegisterOpenAIRoutes(app *echo.Echo,
 	app.POST("/completions", completionHandler, completionMiddleware...)
 	app.POST("/v1/engines/:model/completions", completionHandler, completionMiddleware...)
 
-	// MCPcompletion
-	mcpCompletionHandler := openai.MCPCompletionEndpoint(application.ModelConfigLoader(), application.ModelLoader(), application.TemplatesEvaluator(), application.ApplicationConfig())
-	mcpCompletionMiddleware := []echo.MiddlewareFunc{
-		traceMiddleware,
-		re.BuildFilteredFirstAvailableDefaultModel(config.BuildUsecaseFilterFn(config.FLAG_CHAT)),
-		re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }),
-		func(next echo.HandlerFunc) echo.HandlerFunc {
-			return func(c echo.Context) error {
-				if err := re.SetOpenAIRequest(c); err != nil {
-					return err
-				}
-				return next(c)
-			}
-		},
-	}
-	app.POST("/mcp/v1/chat/completions", mcpCompletionHandler, mcpCompletionMiddleware...)
-	app.POST("/mcp/chat/completions", mcpCompletionHandler, mcpCompletionMiddleware...)
+	// Note: MCP endpoints are registered in localai.go to avoid route conflicts
+	// The localai.MCPStreamEndpoint handler supports both streaming and non-streaming modes
 
 	// embeddings
 	embeddingHandler := openai.EmbeddingsEndpoint(application.ModelConfigLoader(), application.ModelLoader(), application.ApplicationConfig())

core/http/routes/ui_api.go

@@ -954,7 +954,7 @@ func RegisterUIAPIRoutes(app *echo.Echo, cl *config.ModelConfigLoader, ml *model
 		if !appConfig.EnableTracing {
 			return c.JSON(503, map[string]any{
 				"error": "Tracing disabled",
-				})
+			})
 		}
 		traces := middleware.GetTraces()
 		return c.JSON(200, map[string]interface{}{