Implements unified model routing

Migrates the AMP module to a new unified routing system, replacing the fallback handler with a router-based approach.

This change introduces a `ModelRoutingWrapper` that handles model extraction, routing decisions, and proxying based on provider availability and model mappings.
It provides a more flexible and maintainable routing mechanism by centralizing routing logic.

The changes include:
- Introducing new `routing` package with core routing logic.
- Creating characterization tests to capture existing behavior.
- Implementing model extraction and rewriting.
- Updating AMP module routes to utilize the new routing wrapper.
- Deprecating `FallbackHandler` in favor of the new `ModelRoutingWrapper`.

internal/api/modules/amp/fallback_handlers.go

@@ -86,6 +86,10 @@ func logAmpRouting(routeType AmpRouteType, requestedModel, resolvedModel, provid
 
 // FallbackHandler wraps a standard handler with fallback logic to ampcode.com
 // when the model's provider is not available in CLIProxyAPI
+//
+// Deprecated: FallbackHandler is deprecated in favor of routing.ModelRoutingWrapper.
+// Use routing.NewModelRoutingWrapper() instead for unified routing logic.
+// This type is kept for backward compatibility and test purposes.
 type FallbackHandler struct {
 	getProxy           func() *httputil.ReverseProxy
 	modelMapper        ModelMapper
@@ -94,6 +98,8 @@ type FallbackHandler struct {
 
 // NewFallbackHandler creates a new fallback handler wrapper
 // The getProxy function allows lazy evaluation of the proxy (useful when proxy is created after routes)
+//
+// Deprecated: Use routing.NewModelRoutingWrapper() instead.
 func NewFallbackHandler(getProxy func() *httputil.ReverseProxy) *FallbackHandler {
 	return &FallbackHandler{
 		getProxy:           getProxy,
@@ -102,6 +108,8 @@ func NewFallbackHandler(getProxy func() *httputil.ReverseProxy) *FallbackHandler
 }
 
 // NewFallbackHandlerWithMapper creates a new fallback handler with model mapping support
+//
+// Deprecated: Use routing.NewModelRoutingWrapper() instead.
 func NewFallbackHandlerWithMapper(getProxy func() *httputil.ReverseProxy, mapper ModelMapper, forceModelMappings func() bool) *FallbackHandler {
 	if forceModelMappings == nil {
 		forceModelMappings = func() bool { return false }

internal/api/modules/amp/fallback_handlers_characterization_test.go

@@ -0,0 +1,326 @@
+package amp
+
+import (
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/routing/testutil"
+	"github.com/stretchr/testify/assert"
+)
+
+// Characterization tests for fallback_handlers.go using testutil recorders
+// These tests capture existing behavior before refactoring to routing layer
+
+func TestCharacterization_LocalProvider(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Register a mock provider for the test model
+	reg := registry.GetGlobalRegistry()
+	reg.RegisterClient("char-test-local", "anthropic", []*registry.ModelInfo{
+		{ID: "test-model-local"},
+	})
+	defer reg.UnregisterClient("char-test-local")
+
+	// Setup recorders
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create gin context
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+
+	body := `{"model": "test-model-local", "messages": [{"role": "user", "content": "hello"}]}`
+	req := httptest.NewRequest(http.MethodPost, "/api/provider/anthropic/v1/messages", bytes.NewReader([]byte(body)))
+	req.Header.Set("Content-Type", "application/json")
+	c.Request = req
+
+	// Create fallback handler with proxy recorder
+	// Create a test server to act as the proxy target
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	fh := NewFallbackHandler(func() *httputil.ReverseProxy {
+		// Create a reverse proxy that forwards to our test server
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	})
+
+	// Execute
+	wrapped := fh.WrapHandler(handlerRecorder.GinHandler())
+	wrapped(c)
+
+	// Assert: proxy NOT called
+	assert.False(t, proxyRecorder.Called, "proxy should NOT be called for local provider")
+
+	// Assert: local handler called once
+	assert.True(t, handlerRecorder.WasCalled(), "local handler should be called")
+	assert.Equal(t, 1, handlerRecorder.GetCallCount(), "local handler should be called exactly once")
+
+	// Assert: request body model unchanged
+	assert.Contains(t, string(handlerRecorder.RequestBody), "test-model-local", "request body model should be unchanged")
+}
+
+func TestCharacterization_ModelMapping(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Register a mock provider for the TARGET model (the mapped-to model)
+	reg := registry.GetGlobalRegistry()
+	reg.RegisterClient("char-test-mapped", "openai", []*registry.ModelInfo{
+		{ID: "gpt-4-local"},
+	})
+	defer reg.UnregisterClient("char-test-mapped")
+
+	// Setup recorders
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create model mapper with a mapping
+	mapper := NewModelMapper([]config.AmpModelMapping{
+		{From: "gpt-4-turbo", To: "gpt-4-local"},
+	})
+
+	// Create gin context
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+
+	// Request with original model that gets mapped
+	body := `{"model": "gpt-4-turbo", "messages": [{"role": "user", "content": "hello"}]}`
+	req := httptest.NewRequest(http.MethodPost, "/api/provider/openai/v1/chat/completions", bytes.NewReader([]byte(body)))
+	req.Header.Set("Content-Type", "application/json")
+	c.Request = req
+
+	// Create fallback handler with mapper
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	fh := NewFallbackHandlerWithMapper(func() *httputil.ReverseProxy {
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	}, mapper, func() bool { return false })
+
+	// Execute - use handler that returns model in response for rewriter to work
+	wrapped := fh.WrapHandler(handlerRecorder.GinHandlerWithModel())
+	wrapped(c)
+
+	// Assert: proxy NOT called
+	assert.False(t, proxyRecorder.Called, "proxy should NOT be called for model mapping")
+
+	// Assert: local handler called once
+	assert.True(t, handlerRecorder.WasCalled(), "local handler should be called")
+	assert.Equal(t, 1, handlerRecorder.GetCallCount(), "local handler should be called exactly once")
+
+	// Assert: request body model was rewritten to mapped model
+	assert.Contains(t, string(handlerRecorder.RequestBody), "gpt-4-local", "request body model should be rewritten to mapped model")
+	assert.NotContains(t, string(handlerRecorder.RequestBody), "gpt-4-turbo", "request body should NOT contain original model")
+
+	// Assert: context has mapped_model key set
+	mappedModel, exists := handlerRecorder.GetContextKey("mapped_model")
+	assert.True(t, exists, "context should have mapped_model key")
+	assert.Equal(t, "gpt-4-local", mappedModel, "mapped_model should be the target model")
+
+	// Assert: response body model rewritten back to original
+	// The response writer should rewrite model names in the response
+	responseBody := w.Body.String()
+	assert.Contains(t, responseBody, "gpt-4-turbo", "response should have original model name")
+}
+
+func TestCharacterization_AmpCreditsProxy(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Setup recorders - NO local provider registered, NO mapping configured
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create gin context with CloseNotifier support (required for ReverseProxy)
+	w := testutil.NewCloseNotifierRecorder()
+	c, _ := gin.CreateTestContext(w)
+
+	// Request with a model that has no local provider and no mapping
+	body := `{"model": "unknown-model-no-provider", "messages": [{"role": "user", "content": "hello"}]}`
+	req := httptest.NewRequest(http.MethodPost, "/api/provider/openai/v1/chat/completions", bytes.NewReader([]byte(body)))
+	req.Header.Set("Content-Type", "application/json")
+	c.Request = req
+
+	// Create fallback handler
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	fh := NewFallbackHandler(func() *httputil.ReverseProxy {
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	})
+
+	// Execute
+	wrapped := fh.WrapHandler(handlerRecorder.GinHandler())
+	wrapped(c)
+
+	// Assert: proxy called once
+	assert.True(t, proxyRecorder.Called, "proxy should be called when no local provider and no mapping")
+	assert.Equal(t, 1, proxyRecorder.GetCallCount(), "proxy should be called exactly once")
+
+	// Assert: local handler NOT called
+	assert.False(t, handlerRecorder.WasCalled(), "local handler should NOT be called when falling back to proxy")
+
+	// Assert: body forwarded to proxy is original (no rewrite)
+	assert.Contains(t, string(proxyRecorder.RequestBody), "unknown-model-no-provider", "request body model should be unchanged when proxying")
+}
+
+func TestCharacterization_BodyRestore(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Register a mock provider for the test model
+	reg := registry.GetGlobalRegistry()
+	reg.RegisterClient("char-test-body", "anthropic", []*registry.ModelInfo{
+		{ID: "test-model-body"},
+	})
+	defer reg.UnregisterClient("char-test-body")
+
+	// Setup recorders
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create gin context
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+
+	// Create a complex request body that will be read by the wrapper for model extraction
+	originalBody := `{"model": "test-model-body", "messages": [{"role": "user", "content": "hello"}], "temperature": 0.7, "stream": true}`
+	req := httptest.NewRequest(http.MethodPost, "/api/provider/anthropic/v1/messages", bytes.NewReader([]byte(originalBody)))
+	req.Header.Set("Content-Type", "application/json")
+	c.Request = req
+
+	// Create fallback handler with proxy recorder
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	fh := NewFallbackHandler(func() *httputil.ReverseProxy {
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	})
+
+	// Execute
+	wrapped := fh.WrapHandler(handlerRecorder.GinHandler())
+	wrapped(c)
+
+	// Assert: local handler called (not proxy, since we have a local provider)
+	assert.True(t, handlerRecorder.WasCalled(), "local handler should be called")
+	assert.False(t, proxyRecorder.Called, "proxy should NOT be called for local provider")
+
+	// Assert: handler receives complete original body
+	// This verifies that the body was properly restored after the wrapper read it for model extraction
+	assert.Equal(t, originalBody, string(handlerRecorder.RequestBody), "handler should receive complete original body after wrapper reads it for model extraction")
+}
+
+// TestCharacterization_GeminiV1Beta1_PostModels tests that POST requests with /models/ path use Gemini bridge handler
+// This is a characterization test for the route gating logic in routes.go
+func TestCharacterization_GeminiV1Beta1_PostModels(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Register a mock provider for the test model (Gemini format uses path-based model extraction)
+	reg := registry.GetGlobalRegistry()
+	reg.RegisterClient("char-test-gemini", "google", []*registry.ModelInfo{
+		{ID: "gemini-pro"},
+	})
+	defer reg.UnregisterClient("char-test-gemini")
+
+	// Setup recorders
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create a test server for the proxy
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	// Create fallback handler
+	fh := NewFallbackHandler(func() *httputil.ReverseProxy {
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	})
+
+	// Create the Gemini bridge handler (simulating what routes.go does)
+	geminiBridge := createGeminiBridgeHandler(handlerRecorder.GinHandler())
+	geminiV1Beta1Handler := fh.WrapHandler(geminiBridge)
+
+	// Create router with the same gating logic as routes.go
+	r := gin.New()
+	r.Any("/api/provider/google/v1beta1/*path", func(c *gin.Context) {
+		if c.Request.Method == "POST" {
+			if path := c.Param("path"); strings.Contains(path, "/models/") {
+				// POST with /models/ path -> use Gemini bridge with fallback handler
+				geminiV1Beta1Handler(c)
+				return
+			}
+		}
+		// Non-POST or no /models/ in path -> proxy upstream
+		proxyRecorder.ServeHTTP(c.Writer, c.Request)
+	})
+
+	// Execute: POST request with /models/ in path
+	body := `{"contents": [{"role": "user", "parts": [{"text": "hello"}]}]}`
+	req := httptest.NewRequest(http.MethodPost, "/api/provider/google/v1beta1/publishers/google/models/gemini-pro:generateContent", bytes.NewReader([]byte(body)))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+
+	// Assert: local Gemini handler called
+	assert.True(t, handlerRecorder.WasCalled(), "local Gemini handler should be called for POST /models/")
+
+	// Assert: proxy NOT called
+	assert.False(t, proxyRecorder.Called, "proxy should NOT be called for POST /models/ path")
+}
+
+// TestCharacterization_GeminiV1Beta1_GetProxies tests that GET requests to Gemini v1beta1 always use proxy
+// This is a characterization test for the route gating logic in routes.go
+func TestCharacterization_GeminiV1Beta1_GetProxies(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	// Setup recorders
+	proxyRecorder := testutil.NewFakeProxyRecorder()
+	handlerRecorder := testutil.NewFakeHandlerRecorder()
+
+	// Create a test server for the proxy
+	proxyServer := httptest.NewServer(proxyRecorder.ToHandler())
+	defer proxyServer.Close()
+
+	// Create fallback handler
+	fh := NewFallbackHandler(func() *httputil.ReverseProxy {
+		targetURL, _ := url.Parse(proxyServer.URL)
+		return httputil.NewSingleHostReverseProxy(targetURL)
+	})
+
+	// Create the Gemini bridge handler
+	geminiBridge := createGeminiBridgeHandler(handlerRecorder.GinHandler())
+	geminiV1Beta1Handler := fh.WrapHandler(geminiBridge)
+
+	// Create router with the same gating logic as routes.go
+	r := gin.New()
+	r.Any("/api/provider/google/v1beta1/*path", func(c *gin.Context) {
+		if c.Request.Method == "POST" {
+			if path := c.Param("path"); strings.Contains(path, "/models/") {
+				geminiV1Beta1Handler(c)
+				return
+			}
+		}
+		proxyRecorder.ServeHTTP(c.Writer, c.Request)
+	})
+
+	// Execute: GET request (even with /models/ in path)
+	req := httptest.NewRequest(http.MethodGet, "/api/provider/google/v1beta1/publishers/google/models/gemini-pro", nil)
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+
+	// Assert: proxy called
+	assert.True(t, proxyRecorder.Called, "proxy should be called for GET requests")
+	assert.Equal(t, 1, proxyRecorder.GetCallCount(), "proxy should be called exactly once")
+
+	// Assert: local handler NOT called
+	assert.False(t, handlerRecorder.WasCalled(), "local handler should NOT be called for GET requests")
+}

internal/api/modules/amp/model_mapping.go

@@ -276,6 +276,22 @@ func (m *DefaultModelMapper) GetMappings() map[string]string {
 	return result
 }
 
+// GetMappingsAsConfig returns the current model mappings as config.AmpModelMapping slice.
+// Safe for concurrent use.
+func (m *DefaultModelMapper) GetMappingsAsConfig() []config.AmpModelMapping {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	result := make([]config.AmpModelMapping, 0, len(m.mappings))
+	for from, to := range m.mappings {
+		result = append(result, config.AmpModelMapping{
+			From: from,
+			To:   to,
+		})
+	}
+	return result
+}
+
 type regexMapping struct {
 	re *regexp.Regexp
 	to string

internal/api/modules/amp/routes.go

@@ -5,11 +5,12 @@ import (
 	"errors"
 	"net"
 	"net/http"
-	"net/http/httputil"
 	"strings"
 
 	"github.com/gin-gonic/gin"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/logging"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/routing"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers/claude"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers/gemini"
@@ -234,19 +235,20 @@ func (m *AmpModule) registerManagementRoutes(engine *gin.Engine, baseHandler *ha
 	// If no local OAuth is available, falls back to ampcode.com proxy.
 	geminiHandlers := gemini.NewGeminiAPIHandler(baseHandler)
 	geminiBridge := createGeminiBridgeHandler(geminiHandlers.GeminiHandler)
-	geminiV1Beta1Fallback := NewFallbackHandlerWithMapper(func() *httputil.ReverseProxy {
-		return m.getProxy()
-	}, m.modelMapper, m.forceModelMappings)
-	geminiV1Beta1Handler := geminiV1Beta1Fallback.WrapHandler(geminiBridge)
 
-	// Route POST model calls through Gemini bridge with FallbackHandler.
-	// FallbackHandler checks provider -> mapping -> proxy fallback automatically.
+	// T-025: Migrated Gemini v1beta1 bridge to use ModelRoutingWrapper
+	// Create a dedicated routing wrapper for the Gemini bridge
+	geminiBridgeWrapper := m.createModelRoutingWrapper()
+	geminiV1Beta1Handler := geminiBridgeWrapper.Wrap(geminiBridge)
+
+	// Route POST model calls through Gemini bridge with ModelRoutingWrapper.
+	// ModelRoutingWrapper checks provider -> mapping -> proxy fallback automatically.
 	// All other methods (e.g., GET model listing) always proxy to upstream to preserve Amp CLI behavior.
 	ampAPI.Any("/provider/google/v1beta1/*path", func(c *gin.Context) {
 		if c.Request.Method == "POST" {
 			if path := c.Param("path"); strings.Contains(path, "/models/") {
-				// POST with /models/ path -> use Gemini bridge with fallback handler
-				// FallbackHandler will check provider/mapping and proxy if needed
+				// POST with /models/ path -> use Gemini bridge with unified routing wrapper
+				// ModelRoutingWrapper will check provider/mapping and proxy if needed
 				geminiV1Beta1Handler(c)
 				return
 			}
@@ -256,6 +258,41 @@ func (m *AmpModule) registerManagementRoutes(engine *gin.Engine, baseHandler *ha
 	})
 }
 
+// createModelRoutingWrapper creates a new ModelRoutingWrapper for unified routing.
+// This is used for testing the new routing implementation (T-021 onwards).
+func (m *AmpModule) createModelRoutingWrapper() *routing.ModelRoutingWrapper {
+	// Create a registry - in production this would be populated with actual providers
+	registry := routing.NewRegistry()
+
+	// Create a minimal config with just AmpCode settings
+	// The Router only needs AmpCode.ModelMappings and OAuthModelAlias
+	cfg := &config.Config{
+		AmpCode: func() config.AmpCode {
+			if m.modelMapper != nil {
+				return config.AmpCode{
+					ModelMappings: m.modelMapper.GetMappingsAsConfig(),
+				}
+			}
+			return config.AmpCode{}
+		}(),
+	}
+
+	// Create router with registry and config
+	router := routing.NewRouter(registry, cfg)
+
+	// Create wrapper with proxy function
+	proxyFunc := func(c *gin.Context) {
+		proxy := m.getProxy()
+		if proxy != nil {
+			proxy.ServeHTTP(c.Writer, c.Request)
+		} else {
+			c.JSON(503, gin.H{"error": "amp upstream proxy not available"})
+		}
+	}
+
+	return routing.NewModelRoutingWrapper(router, nil, nil, proxyFunc)
+}
+
 // registerProviderAliases registers /api/provider/{provider}/... routes
 // These allow Amp CLI to route requests like:
 //
@@ -269,12 +306,9 @@ func (m *AmpModule) registerProviderAliases(engine *gin.Engine, baseHandler *han
 	claudeCodeHandlers := claude.NewClaudeCodeAPIHandler(baseHandler)
 	openaiResponsesHandlers := openai.NewOpenAIResponsesAPIHandler(baseHandler)
 
-	// Create fallback handler wrapper that forwards to ampcode.com when provider not found
-	// Uses m.getProxy() for hot-reload support (proxy can be updated at runtime)
-	// Also includes model mapping support for routing unavailable models to alternatives
-	fallbackHandler := NewFallbackHandlerWithMapper(func() *httputil.ReverseProxy {
-		return m.getProxy()
-	}, m.modelMapper, m.forceModelMappings)
+	// Create unified routing wrapper (T-021 onwards)
+	// Replaces FallbackHandler with Router-based unified routing
+	routingWrapper := m.createModelRoutingWrapper()
 
 	// Provider-specific routes under /api/provider/:provider
 	ampProviders := engine.Group("/api/provider")
@@ -302,33 +336,36 @@ func (m *AmpModule) registerProviderAliases(engine *gin.Engine, baseHandler *han
 	}
 
 	// Root-level routes (for providers that omit /v1, like groq/cerebras)
-	// Wrap handlers with fallback logic to forward to ampcode.com when provider not found
+	// T-022: Migrated all OpenAI routes to use ModelRoutingWrapper for unified routing
 	provider.GET("/models", ampModelsHandler) // Models endpoint doesn't need fallback (no body to check)
-	provider.POST("/chat/completions", fallbackHandler.WrapHandler(openaiHandlers.ChatCompletions))
-	provider.POST("/completions", fallbackHandler.WrapHandler(openaiHandlers.Completions))
-	provider.POST("/responses", fallbackHandler.WrapHandler(openaiResponsesHandlers.Responses))
+	provider.POST("/chat/completions", routingWrapper.Wrap(openaiHandlers.ChatCompletions))
+	provider.POST("/completions", routingWrapper.Wrap(openaiHandlers.Completions))
+	provider.POST("/responses", routingWrapper.Wrap(openaiResponsesHandlers.Responses))
 
 	// /v1 routes (OpenAI/Claude-compatible endpoints)
 	v1Amp := provider.Group("/v1")
 	{
 		v1Amp.GET("/models", ampModelsHandler) // Models endpoint doesn't need fallback
 
-		// OpenAI-compatible endpoints with fallback
-		v1Amp.POST("/chat/completions", fallbackHandler.WrapHandler(openaiHandlers.ChatCompletions))
-		v1Amp.POST("/completions", fallbackHandler.WrapHandler(openaiHandlers.Completions))
-		v1Amp.POST("/responses", fallbackHandler.WrapHandler(openaiResponsesHandlers.Responses))
+		// OpenAI-compatible endpoints with ModelRoutingWrapper
+		// T-021, T-022: Migrated to unified routing wrapper
+		v1Amp.POST("/chat/completions", routingWrapper.Wrap(openaiHandlers.ChatCompletions))
+		v1Amp.POST("/completions", routingWrapper.Wrap(openaiHandlers.Completions))
+		v1Amp.POST("/responses", routingWrapper.Wrap(openaiResponsesHandlers.Responses))
 
-		// Claude/Anthropic-compatible endpoints with fallback
-		v1Amp.POST("/messages", fallbackHandler.WrapHandler(claudeCodeHandlers.ClaudeMessages))
-		v1Amp.POST("/messages/count_tokens", fallbackHandler.WrapHandler(claudeCodeHandlers.ClaudeCountTokens))
+		// Claude/Anthropic-compatible endpoints with ModelRoutingWrapper
+		// T-023: Migrated Claude routes to unified routing wrapper
+		v1Amp.POST("/messages", routingWrapper.Wrap(claudeCodeHandlers.ClaudeMessages))
+		v1Amp.POST("/messages/count_tokens", routingWrapper.Wrap(claudeCodeHandlers.ClaudeCountTokens))
 	}
 
 	// /v1beta routes (Gemini native API)
 	// Note: Gemini handler extracts model from URL path, so fallback logic needs special handling
+	// T-024: Migrated Gemini v1beta routes to unified routing wrapper
 	v1betaAmp := provider.Group("/v1beta")
 	{
 		v1betaAmp.GET("/models", geminiHandlers.GeminiModels)
-		v1betaAmp.POST("/models/*action", fallbackHandler.WrapHandler(geminiHandlers.GeminiHandler))
+		v1betaAmp.POST("/models/*action", routingWrapper.Wrap(geminiHandlers.GeminiHandler))
 		v1betaAmp.GET("/models/*action", geminiHandlers.GeminiGetHandler)
 	}
 }