Merge pull request #1108 from router-for-me/modelinfo

feat(registry): support provider-specific model info lookup

internal/registry/model_definitions.go

@@ -287,6 +287,67 @@ func GetGeminiVertexModels() []*ModelInfo {
 			SupportedGenerationMethods: []string{"generateContent", "countTokens", "createCachedContent", "batchGenerateContent"},
 			Thinking:                   &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"low", "high"}},
 		},
+		// Imagen image generation models - use :predict action
+		{
+			ID:                         "imagen-4.0-generate-001",
+			Object:                     "model",
+			Created:                    1750000000,
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/imagen-4.0-generate-001",
+			Version:                    "4.0",
+			DisplayName:                "Imagen 4.0 Generate",
+			Description:                "Imagen 4.0 image generation model",
+			SupportedGenerationMethods: []string{"predict"},
+		},
+		{
+			ID:                         "imagen-4.0-ultra-generate-001",
+			Object:                     "model",
+			Created:                    1750000000,
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/imagen-4.0-ultra-generate-001",
+			Version:                    "4.0",
+			DisplayName:                "Imagen 4.0 Ultra Generate",
+			Description:                "Imagen 4.0 Ultra high-quality image generation model",
+			SupportedGenerationMethods: []string{"predict"},
+		},
+		{
+			ID:                         "imagen-3.0-generate-002",
+			Object:                     "model",
+			Created:                    1740000000,
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/imagen-3.0-generate-002",
+			Version:                    "3.0",
+			DisplayName:                "Imagen 3.0 Generate",
+			Description:                "Imagen 3.0 image generation model",
+			SupportedGenerationMethods: []string{"predict"},
+		},
+		{
+			ID:                         "imagen-3.0-fast-generate-001",
+			Object:                     "model",
+			Created:                    1740000000,
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/imagen-3.0-fast-generate-001",
+			Version:                    "3.0",
+			DisplayName:                "Imagen 3.0 Fast Generate",
+			Description:                "Imagen 3.0 fast image generation model",
+			SupportedGenerationMethods: []string{"predict"},
+		},
+		{
+			ID:                         "imagen-4.0-fast-generate-001",
+			Object:                     "model",
+			Created:                    1750000000,
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/imagen-4.0-fast-generate-001",
+			Version:                    "4.0",
+			DisplayName:                "Imagen 4.0 Fast Generate",
+			Description:                "Imagen 4.0 fast image generation model",
+			SupportedGenerationMethods: []string{"predict"},
+		},
 	}
 }
 
@@ -765,21 +826,23 @@ func GetIFlowModels() []*ModelInfo {
 type AntigravityModelConfig struct {
 	Thinking            *ThinkingSupport
 	MaxCompletionTokens int
-	Name                string
 }
 
 // GetAntigravityModelConfig returns static configuration for antigravity models.
 // Keys use upstream model names returned by the Antigravity models endpoint.
 func GetAntigravityModelConfig() map[string]*AntigravityModelConfig {
 	return map[string]*AntigravityModelConfig{
-		"gemini-2.5-flash":           {Thinking: &ThinkingSupport{Min: 0, Max: 24576, ZeroAllowed: true, DynamicAllowed: true}, Name: "models/gemini-2.5-flash"},
-		"gemini-2.5-flash-lite":      {Thinking: &ThinkingSupport{Min: 0, Max: 24576, ZeroAllowed: true, DynamicAllowed: true}, Name: "models/gemini-2.5-flash-lite"},
-		"rev19-uic3-1p":              {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true}, Name: "models/rev19-uic3-1p"},
-		"gemini-3-pro-high":          {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"low", "high"}}, Name: "models/gemini-3-pro-high"},
-		"gemini-3-pro-image":         {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"low", "high"}}, Name: "models/gemini-3-pro-image"},
-		"gemini-3-flash":             {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"minimal", "low", "medium", "high"}}, Name: "models/gemini-3-flash"},
+		"gemini-2.5-flash":           {Thinking: &ThinkingSupport{Min: 0, Max: 24576, ZeroAllowed: true, DynamicAllowed: true}},
+		"gemini-2.5-flash-lite":      {Thinking: &ThinkingSupport{Min: 0, Max: 24576, ZeroAllowed: true, DynamicAllowed: true}},
+		"rev19-uic3-1p":              {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true}},
+		"gemini-3-pro-high":          {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"low", "high"}}},
+		"gemini-3-pro-image":         {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"low", "high"}}},
+		"gemini-3-flash":             {Thinking: &ThinkingSupport{Min: 128, Max: 32768, ZeroAllowed: false, DynamicAllowed: true, Levels: []string{"minimal", "low", "medium", "high"}}},
 		"claude-sonnet-4-5-thinking": {Thinking: &ThinkingSupport{Min: 1024, Max: 128000, ZeroAllowed: true, DynamicAllowed: true}, MaxCompletionTokens: 64000},
 		"claude-opus-4-5-thinking":   {Thinking: &ThinkingSupport{Min: 1024, Max: 128000, ZeroAllowed: true, DynamicAllowed: true}, MaxCompletionTokens: 64000},
+		"claude-sonnet-4-5":          {MaxCompletionTokens: 64000},
+		"gpt-oss-120b-medium":        {},
+		"tab_flash_lite_preview":     {},
 	}
 }
 
@@ -809,10 +872,9 @@ func LookupStaticModelInfo(modelID string) *ModelInfo {
 	}
 
 	// Check Antigravity static config
-	if cfg := GetAntigravityModelConfig()[modelID]; cfg != nil && cfg.Thinking != nil {
+	if cfg := GetAntigravityModelConfig()[modelID]; cfg != nil {
 		return &ModelInfo{
 			ID:                  modelID,
-			Name:                cfg.Name,
 			Thinking:            cfg.Thinking,
 			MaxCompletionTokens: cfg.MaxCompletionTokens,
 		}

internal/registry/model_registry.go

@@ -78,6 +78,8 @@ type ThinkingSupport struct {
 type ModelRegistration struct {
 	// Info contains the model metadata
 	Info *ModelInfo
+	// InfoByProvider maps provider identifiers to specific ModelInfo to support differing capabilities.
+	InfoByProvider map[string]*ModelInfo
 	// Count is the number of active clients that can provide this model
 	Count int
 	// LastUpdated tracks when this registration was last modified
@@ -132,16 +134,19 @@ func GetGlobalRegistry() *ModelRegistry {
 	return globalRegistry
 }
 
-// LookupModelInfo searches the dynamic registry first, then falls back to static model definitions.
-//
-// This helper exists because some code paths only have a model ID and still need Thinking and
-// max completion token metadata even when the dynamic registry hasn't been populated.
-func LookupModelInfo(modelID string) *ModelInfo {
+// LookupModelInfo searches dynamic registry (provider-specific > global) then static definitions.
+func LookupModelInfo(modelID string, provider ...string) *ModelInfo {
 	modelID = strings.TrimSpace(modelID)
 	if modelID == "" {
 		return nil
 	}
-	if info := GetGlobalRegistry().GetModelInfo(modelID); info != nil {
+
+	p := ""
+	if len(provider) > 0 {
+		p = strings.ToLower(strings.TrimSpace(provider[0]))
+	}
+
+	if info := GetGlobalRegistry().GetModelInfo(modelID, p); info != nil {
 		return info
 	}
 	return LookupStaticModelInfo(modelID)
@@ -297,6 +302,9 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 				if count, okProv := reg.Providers[oldProvider]; okProv {
 					if count <= toRemove {
 						delete(reg.Providers, oldProvider)
+						if reg.InfoByProvider != nil {
+							delete(reg.InfoByProvider, oldProvider)
+						}
 					} else {
 						reg.Providers[oldProvider] = count - toRemove
 					}
@@ -346,6 +354,12 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 		model := newModels[id]
 		if reg, ok := r.models[id]; ok {
 			reg.Info = cloneModelInfo(model)
+			if provider != "" {
+				if reg.InfoByProvider == nil {
+					reg.InfoByProvider = make(map[string]*ModelInfo)
+				}
+				reg.InfoByProvider[provider] = cloneModelInfo(model)
+			}
 			reg.LastUpdated = now
 			if reg.QuotaExceededClients != nil {
 				delete(reg.QuotaExceededClients, clientID)
@@ -409,11 +423,15 @@ func (r *ModelRegistry) addModelRegistration(modelID, provider string, model *Mo
 		if existing.SuspendedClients == nil {
 			existing.SuspendedClients = make(map[string]string)
 		}
+		if existing.InfoByProvider == nil {
+			existing.InfoByProvider = make(map[string]*ModelInfo)
+		}
 		if provider != "" {
 			if existing.Providers == nil {
 				existing.Providers = make(map[string]int)
 			}
 			existing.Providers[provider]++
+			existing.InfoByProvider[provider] = cloneModelInfo(model)
 		}
 		log.Debugf("Incremented count for model %s, now %d clients", modelID, existing.Count)
 		return
@@ -421,6 +439,7 @@ func (r *ModelRegistry) addModelRegistration(modelID, provider string, model *Mo
 
 	registration := &ModelRegistration{
 		Info:                 cloneModelInfo(model),
+		InfoByProvider:       make(map[string]*ModelInfo),
 		Count:                1,
 		LastUpdated:          now,
 		QuotaExceededClients: make(map[string]*time.Time),
@@ -428,6 +447,7 @@ func (r *ModelRegistry) addModelRegistration(modelID, provider string, model *Mo
 	}
 	if provider != "" {
 		registration.Providers = map[string]int{provider: 1}
+		registration.InfoByProvider[provider] = cloneModelInfo(model)
 	}
 	r.models[modelID] = registration
 	log.Debugf("Registered new model %s from provider %s", modelID, provider)
@@ -453,6 +473,9 @@ func (r *ModelRegistry) removeModelRegistration(clientID, modelID, provider stri
 		if count, ok := registration.Providers[provider]; ok {
 			if count <= 1 {
 				delete(registration.Providers, provider)
+				if registration.InfoByProvider != nil {
+					delete(registration.InfoByProvider, provider)
+				}
 			} else {
 				registration.Providers[provider] = count - 1
 			}
@@ -534,6 +557,9 @@ func (r *ModelRegistry) unregisterClientInternal(clientID string) {
 				if count, ok := registration.Providers[provider]; ok {
 					if count <= 1 {
 						delete(registration.Providers, provider)
+						if registration.InfoByProvider != nil {
+							delete(registration.InfoByProvider, provider)
+						}
 					} else {
 						registration.Providers[provider] = count - 1
 					}
@@ -940,12 +966,22 @@ func (r *ModelRegistry) GetModelProviders(modelID string) []string {
 	return result
 }
 
-// GetModelInfo returns the registered ModelInfo for the given model ID, if present.
-// Returns nil if the model is unknown to the registry.
-func (r *ModelRegistry) GetModelInfo(modelID string) *ModelInfo {
+// GetModelInfo returns ModelInfo, prioritizing provider-specific definition if available.
+func (r *ModelRegistry) GetModelInfo(modelID, provider string) *ModelInfo {
 	r.mutex.RLock()
 	defer r.mutex.RUnlock()
 	if reg, ok := r.models[modelID]; ok && reg != nil {
+		// Try provider specific definition first
+		if provider != "" && reg.InfoByProvider != nil {
+			if reg.Providers != nil {
+				if count, ok := reg.Providers[provider]; ok && count > 0 {
+					if info, ok := reg.InfoByProvider[provider]; ok && info != nil {
+						return info
+					}
+				}
+			}
+		}
+		// Fallback to global info (last registered)
 		return reg.Info
 	}
 	return nil

internal/runtime/executor/aistudio_executor.go

@@ -393,7 +393,7 @@ func (e *AIStudioExecutor) translateRequest(req cliproxyexecutor.Request, opts c
 	}
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, stream)
 	payload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), stream)
-	payload, err := thinking.ApplyThinking(payload, req.Model, from.String(), to.String())
+	payload, err := thinking.ApplyThinking(payload, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, translatedPayload{}, err
 	}

internal/runtime/executor/antigravity_executor.go

@@ -137,7 +137,7 @@ func (e *AntigravityExecutor) Execute(ctx context.Context, auth *cliproxyauth.Au
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -256,7 +256,7 @@ func (e *AntigravityExecutor) executeClaudeNonStream(ctx context.Context, auth *
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -622,7 +622,7 @@ func (e *AntigravityExecutor) ExecuteStream(ctx context.Context, auth *cliproxya
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -802,7 +802,7 @@ func (e *AntigravityExecutor) CountTokens(ctx context.Context, auth *cliproxyaut
 	// Prepare payload once (doesn't depend on baseURL)
 	payload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	payload, err := thinking.ApplyThinking(payload, req.Model, from.String(), to.String())
+	payload, err := thinking.ApplyThinking(payload, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}
@@ -1005,9 +1005,6 @@ func FetchAntigravityModels(ctx context.Context, auth *cliproxyauth.Auth, cfg *c
 			}
 			modelCfg := modelConfig[modelID]
 			modelName := modelID
-			if modelCfg != nil && modelCfg.Name != "" {
-				modelName = modelCfg.Name
-			}
 			modelInfo := &registry.ModelInfo{
 				ID:          modelID,
 				Name:        modelName,
@@ -1410,13 +1407,6 @@ func geminiToAntigravity(modelName string, payload []byte, projectID string) []b
 	template, _ = sjson.Delete(template, "request.safetySettings")
 	template, _ = sjson.Set(template, "request.toolConfig.functionCallingConfig.mode", "VALIDATED")
 
-	if !strings.HasPrefix(modelName, "gemini-3-") {
-		if thinkingLevel := gjson.Get(template, "request.generationConfig.thinkingConfig.thinkingLevel"); thinkingLevel.Exists() {
-			template, _ = sjson.Delete(template, "request.generationConfig.thinkingConfig.thinkingLevel")
-			template, _ = sjson.Set(template, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
-		}
-	}
-
 	if strings.Contains(modelName, "claude") {
 		gjson.Get(template, "request.tools").ForEach(func(key, tool gjson.Result) bool {
 			tool.Get("functionDeclarations").ForEach(func(funKey, funcDecl gjson.Result) bool {

internal/runtime/executor/claude_executor.go

@@ -17,7 +17,6 @@ import (
 	claudeauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/claude"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/misc"
-	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/thinking"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
@@ -106,7 +105,7 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), stream)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -119,9 +118,6 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	// Disable thinking if tool_choice forces tool use (Anthropic API constraint)
 	body = disableThinkingIfToolChoiceForced(body)
 
-	// Ensure max_tokens > thinking.budget_tokens when thinking is enabled
-	body = ensureMaxTokensForThinking(baseModel, body)
-
 	// Extract betas from body and convert to header
 	var extraBetas []string
 	extraBetas, body = extractAndRemoveBetas(body)
@@ -239,7 +235,7 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -250,9 +246,6 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	// Disable thinking if tool_choice forces tool use (Anthropic API constraint)
 	body = disableThinkingIfToolChoiceForced(body)
 
-	// Ensure max_tokens > thinking.budget_tokens when thinking is enabled
-	body = ensureMaxTokensForThinking(baseModel, body)
-
 	// Extract betas from body and convert to header
 	var extraBetas []string
 	extraBetas, body = extractAndRemoveBetas(body)
@@ -541,81 +534,6 @@ func disableThinkingIfToolChoiceForced(body []byte) []byte {
 	return body
 }
 
-// ensureMaxTokensForThinking ensures max_tokens > thinking.budget_tokens when thinking is enabled.
-// Anthropic API requires this constraint; violating it returns a 400 error.
-// This function should be called after all thinking configuration is finalized.
-// It looks up the model's MaxCompletionTokens from the registry to use as the cap.
-func ensureMaxTokensForThinking(modelName string, body []byte) []byte {
-	thinkingType := gjson.GetBytes(body, "thinking.type").String()
-	if thinkingType != "enabled" {
-		return body
-	}
-
-	budgetTokens := gjson.GetBytes(body, "thinking.budget_tokens").Int()
-	if budgetTokens <= 0 {
-		return body
-	}
-
-	maxTokens := gjson.GetBytes(body, "max_tokens").Int()
-
-	// Look up the model's max completion tokens from the registry
-	maxCompletionTokens := 0
-	if modelInfo := registry.LookupModelInfo(modelName); modelInfo != nil {
-		maxCompletionTokens = modelInfo.MaxCompletionTokens
-	}
-
-	// Fall back to budget + buffer if registry lookup fails or returns 0
-	const fallbackBuffer = 4000
-	requiredMaxTokens := budgetTokens + fallbackBuffer
-	if maxCompletionTokens > 0 {
-		requiredMaxTokens = int64(maxCompletionTokens)
-	}
-
-	if maxTokens < requiredMaxTokens {
-		body, _ = sjson.SetBytes(body, "max_tokens", requiredMaxTokens)
-	}
-	return body
-}
-
-func (e *ClaudeExecutor) resolveClaudeConfig(auth *cliproxyauth.Auth) *config.ClaudeKey {
-	if auth == nil || e.cfg == nil {
-		return nil
-	}
-	var attrKey, attrBase string
-	if auth.Attributes != nil {
-		attrKey = strings.TrimSpace(auth.Attributes["api_key"])
-		attrBase = strings.TrimSpace(auth.Attributes["base_url"])
-	}
-	for i := range e.cfg.ClaudeKey {
-		entry := &e.cfg.ClaudeKey[i]
-		cfgKey := strings.TrimSpace(entry.APIKey)
-		cfgBase := strings.TrimSpace(entry.BaseURL)
-		if attrKey != "" && attrBase != "" {
-			if strings.EqualFold(cfgKey, attrKey) && strings.EqualFold(cfgBase, attrBase) {
-				return entry
-			}
-			continue
-		}
-		if attrKey != "" && strings.EqualFold(cfgKey, attrKey) {
-			if cfgBase == "" || strings.EqualFold(cfgBase, attrBase) {
-				return entry
-			}
-		}
-		if attrKey == "" && attrBase != "" && strings.EqualFold(cfgBase, attrBase) {
-			return entry
-		}
-	}
-	if attrKey != "" {
-		for i := range e.cfg.ClaudeKey {
-			entry := &e.cfg.ClaudeKey[i]
-			if strings.EqualFold(strings.TrimSpace(entry.APIKey), attrKey) {
-				return entry
-			}
-		}
-	}
-	return nil
-}
-
 type compositeReadCloser struct {
 	io.Reader
 	closers []func() error

internal/runtime/executor/codex_executor.go

@@ -96,7 +96,7 @@ func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	body = sdktranslator.TranslateRequest(from, to, baseModel, body, false)
 	body = misc.StripCodexUserAgent(body)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -208,7 +208,7 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 	body = sdktranslator.TranslateRequest(from, to, baseModel, body, true)
 	body = misc.StripCodexUserAgent(body)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -316,7 +316,7 @@ func (e *CodexExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Auth
 	body = sdktranslator.TranslateRequest(from, to, baseModel, body, false)
 	body = misc.StripCodexUserAgent(body)
 
-	body, err := thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err := thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}

internal/runtime/executor/gemini_cli_executor.go

@@ -123,7 +123,7 @@ func (e *GeminiCLIExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	basePayload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	basePayload, err = thinking.ApplyThinking(basePayload, req.Model, from.String(), to.String())
+	basePayload, err = thinking.ApplyThinking(basePayload, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -272,7 +272,7 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	basePayload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	basePayload, err = thinking.ApplyThinking(basePayload, req.Model, from.String(), to.String())
+	basePayload, err = thinking.ApplyThinking(basePayload, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -479,7 +479,7 @@ func (e *GeminiCLIExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.
 	for range models {
 		payload := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-		payload, err = thinking.ApplyThinking(payload, req.Model, from.String(), to.String())
+		payload, err = thinking.ApplyThinking(payload, req.Model, from.String(), to.String(), e.Identifier())
 		if err != nil {
 			return cliproxyexecutor.Response{}, err
 		}

internal/runtime/executor/gemini_executor.go

@@ -120,7 +120,7 @@ func (e *GeminiExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -222,7 +222,7 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -338,7 +338,7 @@ func (e *GeminiExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Aut
 	to := sdktranslator.FromString("gemini")
 	translatedReq := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String())
+	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}

internal/runtime/executor/gemini_vertex_executor.go

@@ -12,6 +12,7 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"time"
 
 	vertexauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/vertex"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
@@ -31,6 +32,143 @@ const (
 	vertexAPIVersion = "v1"
 )
 
+// isImagenModel checks if the model name is an Imagen image generation model.
+// Imagen models use the :predict action instead of :generateContent.
+func isImagenModel(model string) bool {
+	lowerModel := strings.ToLower(model)
+	return strings.Contains(lowerModel, "imagen")
+}
+
+// getVertexAction returns the appropriate action for the given model.
+// Imagen models use "predict", while Gemini models use "generateContent".
+func getVertexAction(model string, isStream bool) string {
+	if isImagenModel(model) {
+		return "predict"
+	}
+	if isStream {
+		return "streamGenerateContent"
+	}
+	return "generateContent"
+}
+
+// convertImagenToGeminiResponse converts Imagen API response to Gemini format
+// so it can be processed by the standard translation pipeline.
+// This ensures Imagen models return responses in the same format as gemini-3-pro-image-preview.
+func convertImagenToGeminiResponse(data []byte, model string) []byte {
+	predictions := gjson.GetBytes(data, "predictions")
+	if !predictions.Exists() || !predictions.IsArray() {
+		return data
+	}
+
+	// Build Gemini-compatible response with inlineData
+	parts := make([]map[string]any, 0)
+	for _, pred := range predictions.Array() {
+		imageData := pred.Get("bytesBase64Encoded").String()
+		mimeType := pred.Get("mimeType").String()
+		if mimeType == "" {
+			mimeType = "image/png"
+		}
+		if imageData != "" {
+			parts = append(parts, map[string]any{
+				"inlineData": map[string]any{
+					"mimeType": mimeType,
+					"data":     imageData,
+				},
+			})
+		}
+	}
+
+	// Generate unique response ID using timestamp
+	responseId := fmt.Sprintf("imagen-%d", time.Now().UnixNano())
+
+	response := map[string]any{
+		"candidates": []map[string]any{{
+			"content": map[string]any{
+				"parts": parts,
+				"role":  "model",
+			},
+			"finishReason": "STOP",
+		}},
+		"responseId":   responseId,
+		"modelVersion": model,
+		// Imagen API doesn't return token counts, set to 0 for tracking purposes
+		"usageMetadata": map[string]any{
+			"promptTokenCount":     0,
+			"candidatesTokenCount": 0,
+			"totalTokenCount":      0,
+		},
+	}
+
+	result, err := json.Marshal(response)
+	if err != nil {
+		return data
+	}
+	return result
+}
+
+// convertToImagenRequest converts a Gemini-style request to Imagen API format.
+// Imagen API uses a different structure: instances[].prompt instead of contents[].
+func convertToImagenRequest(payload []byte) ([]byte, error) {
+	// Extract prompt from Gemini-style contents
+	prompt := ""
+
+	// Try to get prompt from contents[0].parts[0].text
+	contentsText := gjson.GetBytes(payload, "contents.0.parts.0.text")
+	if contentsText.Exists() {
+		prompt = contentsText.String()
+	}
+
+	// If no contents, try messages format (OpenAI-compatible)
+	if prompt == "" {
+		messagesText := gjson.GetBytes(payload, "messages.#.content")
+		if messagesText.Exists() && messagesText.IsArray() {
+			for _, msg := range messagesText.Array() {
+				if msg.String() != "" {
+					prompt = msg.String()
+					break
+				}
+			}
+		}
+	}
+
+	// If still no prompt, try direct prompt field
+	if prompt == "" {
+		directPrompt := gjson.GetBytes(payload, "prompt")
+		if directPrompt.Exists() {
+			prompt = directPrompt.String()
+		}
+	}
+
+	if prompt == "" {
+		return nil, fmt.Errorf("imagen: no prompt found in request")
+	}
+
+	// Build Imagen API request
+	imagenReq := map[string]any{
+		"instances": []map[string]any{
+			{
+				"prompt": prompt,
+			},
+		},
+		"parameters": map[string]any{
+			"sampleCount": 1,
+		},
+	}
+
+	// Extract optional parameters
+	if aspectRatio := gjson.GetBytes(payload, "aspectRatio"); aspectRatio.Exists() {
+		imagenReq["parameters"].(map[string]any)["aspectRatio"] = aspectRatio.String()
+	}
+	if sampleCount := gjson.GetBytes(payload, "sampleCount"); sampleCount.Exists() {
+		imagenReq["parameters"].(map[string]any)["sampleCount"] = int(sampleCount.Int())
+	}
+	if negativePrompt := gjson.GetBytes(payload, "negativePrompt"); negativePrompt.Exists() {
+		imagenReq["instances"].([]map[string]any)[0]["negativePrompt"] = negativePrompt.String()
+	}
+
+	return json.Marshal(imagenReq)
+}
+
 // GeminiVertexExecutor sends requests to Vertex AI Gemini endpoints using service account credentials.
 type GeminiVertexExecutor struct {
 	cfg *config.Config
@@ -160,26 +298,38 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 	reporter := newUsageReporter(ctx, e.Identifier(), baseModel, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	from := opts.SourceFormat
-	to := sdktranslator.FromString("gemini")
+	var body []byte
 
-	originalPayload := bytes.Clone(req.Payload)
-	if len(opts.OriginalRequest) > 0 {
-		originalPayload = bytes.Clone(opts.OriginalRequest)
-	}
-	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
-	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
+	// Handle Imagen models with special request format
+	if isImagenModel(baseModel) {
+		imagenBody, errImagen := convertToImagenRequest(req.Payload)
+		if errImagen != nil {
+			return resp, errImagen
+		}
+		body = imagenBody
+	} else {
+		// Standard Gemini translation flow
+		from := opts.SourceFormat
+		to := sdktranslator.FromString("gemini")
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
-	if err != nil {
-		return resp, err
+		originalPayload := bytes.Clone(req.Payload)
+		if len(opts.OriginalRequest) > 0 {
+			originalPayload = bytes.Clone(opts.OriginalRequest)
+		}
+		originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
+		body = sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
+
+		body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
+		if err != nil {
+			return resp, err
+		}
+
+		body = fixGeminiImageAspectRatio(baseModel, body)
+		body = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", body, originalTranslated)
+		body, _ = sjson.SetBytes(body, "model", baseModel)
 	}
 
-	body = fixGeminiImageAspectRatio(baseModel, body)
-	body = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", body, originalTranslated)
-	body, _ = sjson.SetBytes(body, "model", baseModel)
-
-	action := "generateContent"
+	action := getVertexAction(baseModel, false)
 	if req.Metadata != nil {
 		if a, _ := req.Metadata["action"].(string); a == "countTokens" {
 			action = "countTokens"
@@ -249,6 +399,16 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 	}
 	appendAPIResponseChunk(ctx, e.cfg, data)
 	reporter.publish(ctx, parseGeminiUsage(data))
+
+	// For Imagen models, convert response to Gemini format before translation
+	// This ensures Imagen responses use the same format as gemini-3-pro-image-preview
+	if isImagenModel(baseModel) {
+		data = convertImagenToGeminiResponse(data, baseModel)
+	}
+
+	// Standard Gemini translation (works for both Gemini and converted Imagen responses)
+	from := opts.SourceFormat
+	to := sdktranslator.FromString("gemini")
 	var param any
 	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
 	resp = cliproxyexecutor.Response{Payload: []byte(out)}
@@ -272,7 +432,7 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, false)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -281,7 +441,7 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	body = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", body, originalTranslated)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	action := "generateContent"
+	action := getVertexAction(baseModel, false)
 	if req.Metadata != nil {
 		if a, _ := req.Metadata["action"].(string); a == "countTokens" {
 			action = "countTokens"
@@ -375,7 +535,7 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -384,12 +544,16 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 	body = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", body, originalTranslated)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
+	action := getVertexAction(baseModel, true)
 	baseURL := vertexBaseURL(location)
-	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, baseModel, "streamGenerateContent")
-	if opts.Alt == "" {
-		url = url + "?alt=sse"
-	} else {
-		url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
+	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, baseModel, action)
+	// Imagen models don't support streaming, skip SSE params
+	if !isImagenModel(baseModel) {
+		if opts.Alt == "" {
+			url = url + "?alt=sse"
+		} else {
+			url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
+		}
 	}
 	body, _ = sjson.DeleteBytes(body, "session_id")
 
@@ -494,7 +658,7 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 	originalTranslated := sdktranslator.TranslateRequest(from, to, baseModel, originalPayload, true)
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -503,15 +667,19 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 	body = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", body, originalTranslated)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
+	action := getVertexAction(baseModel, true)
 	// For API key auth, use simpler URL format without project/location
 	if baseURL == "" {
 		baseURL = "https://generativelanguage.googleapis.com"
 	}
-	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, baseModel, "streamGenerateContent")
-	if opts.Alt == "" {
-		url = url + "?alt=sse"
-	} else {
-		url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
+	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, baseModel, action)
+	// Imagen models don't support streaming, skip SSE params
+	if !isImagenModel(baseModel) {
+		if opts.Alt == "" {
+			url = url + "?alt=sse"
+		} else {
+			url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
+		}
 	}
 	body, _ = sjson.DeleteBytes(body, "session_id")
 
@@ -605,7 +773,7 @@ func (e *GeminiVertexExecutor) countTokensWithServiceAccount(ctx context.Context
 
 	translatedReq := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String())
+	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}
@@ -689,7 +857,7 @@ func (e *GeminiVertexExecutor) countTokensWithAPIKey(ctx context.Context, auth *
 
 	translatedReq := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 
-	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String())
+	translatedReq, err := thinking.ApplyThinking(translatedReq, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}

internal/runtime/executor/iflow_executor.go

@@ -92,7 +92,7 @@ func (e *IFlowExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), "iflow")
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), "iflow", e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -190,7 +190,7 @@ func (e *IFlowExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), "iflow")
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), "iflow", e.Identifier())
 	if err != nil {
 		return nil, err
 	}

internal/runtime/executor/openai_compat_executor.go

@@ -92,7 +92,7 @@ func (e *OpenAICompatExecutor) Execute(ctx context.Context, auth *cliproxyauth.A
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), opts.Stream)
 	translated = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", translated, originalTranslated)
 
-	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -187,7 +187,7 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 	translated := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	translated = applyPayloadConfigWithRoot(e.cfg, baseModel, to.String(), "", translated, originalTranslated)
 
-	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err = thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}
@@ -297,7 +297,7 @@ func (e *OpenAICompatExecutor) CountTokens(ctx context.Context, auth *cliproxyau
 
 	modelForCounting := baseModel
 
-	translated, err := thinking.ApplyThinking(translated, req.Model, from.String(), to.String())
+	translated, err := thinking.ApplyThinking(translated, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return cliproxyexecutor.Response{}, err
 	}

internal/runtime/executor/qwen_executor.go

@@ -86,7 +86,7 @@ func (e *QwenExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), false)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return resp, err
 	}
@@ -172,7 +172,7 @@ func (e *QwenExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Aut
 	body := sdktranslator.TranslateRequest(from, to, baseModel, bytes.Clone(req.Payload), true)
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 
-	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String())
+	body, err = thinking.ApplyThinking(body, req.Model, from.String(), to.String(), e.Identifier())
 	if err != nil {
 		return nil, err
 	}

internal/thinking/apply.go

@@ -63,6 +63,7 @@ func IsUserDefinedModel(modelInfo *registry.ModelInfo) bool {
 //   - model: Model name, optionally with thinking suffix (e.g., "claude-sonnet-4-5(16384)")
 //   - fromFormat: Source request format (e.g., openai, codex, gemini)
 //   - toFormat: Target provider format for the request body (gemini, gemini-cli, antigravity, claude, openai, codex, iflow)
+//   - providerKey: Provider identifier used for registry model lookups (may differ from toFormat, e.g., openrouter -> openai)
 //
 // Returns:
 //   - Modified request body JSON with thinking configuration applied
@@ -79,12 +80,16 @@ func IsUserDefinedModel(modelInfo *registry.ModelInfo) bool {
 // Example:
 //
 //	// With suffix - suffix config takes priority
-//	result, err := thinking.ApplyThinking(body, "gemini-2.5-pro(8192)", "gemini", "gemini")
+//	result, err := thinking.ApplyThinking(body, "gemini-2.5-pro(8192)", "gemini", "gemini", "gemini")
 //
 //	// Without suffix - uses body config
-//	result, err := thinking.ApplyThinking(body, "gemini-2.5-pro", "gemini", "gemini")
-func ApplyThinking(body []byte, model string, fromFormat string, toFormat string) ([]byte, error) {
+//	result, err := thinking.ApplyThinking(body, "gemini-2.5-pro", "gemini", "gemini", "gemini")
+func ApplyThinking(body []byte, model string, fromFormat string, toFormat string, providerKey string) ([]byte, error) {
 	providerFormat := strings.ToLower(strings.TrimSpace(toFormat))
+	providerKey = strings.ToLower(strings.TrimSpace(providerKey))
+	if providerKey == "" {
+		providerKey = providerFormat
+	}
 	fromFormat = strings.ToLower(strings.TrimSpace(fromFormat))
 	if fromFormat == "" {
 		fromFormat = providerFormat
@@ -102,7 +107,8 @@ func ApplyThinking(body []byte, model string, fromFormat string, toFormat string
 	// 2. Parse suffix and get modelInfo
 	suffixResult := ParseSuffix(model)
 	baseModel := suffixResult.ModelName
-	modelInfo := registry.LookupModelInfo(baseModel)
+	// Use provider-specific lookup to handle capability differences across providers.
+	modelInfo := registry.LookupModelInfo(baseModel, providerKey)
 
 	// 3. Model capability check
 	// Unknown models are treated as user-defined so thinking config can still be applied.

internal/thinking/provider/claude/apply.go

@@ -80,9 +80,66 @@ func (a *Applier) Apply(body []byte, config thinking.ThinkingConfig, modelInfo *
 
 	result, _ := sjson.SetBytes(body, "thinking.type", "enabled")
 	result, _ = sjson.SetBytes(result, "thinking.budget_tokens", config.Budget)
+
+	// Ensure max_tokens > thinking.budget_tokens (Anthropic API constraint)
+	result = a.normalizeClaudeBudget(result, config.Budget, modelInfo)
 	return result, nil
 }
 
+// normalizeClaudeBudget applies Claude-specific constraints to ensure max_tokens > budget_tokens.
+// Anthropic API requires this constraint; violating it returns a 400 error.
+func (a *Applier) normalizeClaudeBudget(body []byte, budgetTokens int, modelInfo *registry.ModelInfo) []byte {
+	if budgetTokens <= 0 {
+		return body
+	}
+
+	// Ensure the request satisfies Claude constraints:
+	//  1) Determine effective max_tokens (request overrides model default)
+	//  2) If budget_tokens >= max_tokens, reduce budget_tokens to max_tokens-1
+	//  3) If the adjusted budget falls below the model minimum, leave the request unchanged
+	//  4) If max_tokens came from model default, write it back into the request
+
+	effectiveMax, setDefaultMax := a.effectiveMaxTokens(body, modelInfo)
+	if setDefaultMax && effectiveMax > 0 {
+		body, _ = sjson.SetBytes(body, "max_tokens", effectiveMax)
+	}
+
+	// Compute the budget we would apply after enforcing budget_tokens < max_tokens.
+	adjustedBudget := budgetTokens
+	if effectiveMax > 0 && adjustedBudget >= effectiveMax {
+		adjustedBudget = effectiveMax - 1
+	}
+
+	minBudget := 0
+	if modelInfo != nil && modelInfo.Thinking != nil {
+		minBudget = modelInfo.Thinking.Min
+	}
+	if minBudget > 0 && adjustedBudget > 0 && adjustedBudget < minBudget {
+		// If enforcing the max_tokens constraint would push the budget below the model minimum,
+		// leave the request unchanged.
+		return body
+	}
+
+	if adjustedBudget != budgetTokens {
+		body, _ = sjson.SetBytes(body, "thinking.budget_tokens", adjustedBudget)
+	}
+
+	return body
+}
+
+// effectiveMaxTokens returns the max tokens to cap thinking:
+// prefer request-provided max_tokens; otherwise fall back to model default.
+// The boolean indicates whether the value came from the model default (and thus should be written back).
+func (a *Applier) effectiveMaxTokens(body []byte, modelInfo *registry.ModelInfo) (max int, fromModel bool) {
+	if maxTok := gjson.GetBytes(body, "max_tokens"); maxTok.Exists() && maxTok.Int() > 0 {
+		return int(maxTok.Int()), false
+	}
+	if modelInfo != nil && modelInfo.MaxCompletionTokens > 0 {
+		return modelInfo.MaxCompletionTokens, true
+	}
+	return 0, false
+}
+
 func applyCompatibleClaude(body []byte, config thinking.ThinkingConfig) ([]byte, error) {
 	if config.Mode != thinking.ModeBudget && config.Mode != thinking.ModeNone && config.Mode != thinking.ModeAuto {
 		return body, nil

internal/translator/antigravity/claude/antigravity_claude_request.go

@@ -124,11 +124,11 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 					if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "thinking" {
 						// Use GetThinkingText to handle wrapped thinking objects
 						thinkingText := thinking.GetThinkingText(contentResult)
-						signatureResult := contentResult.Get("signature")
-						clientSignature := ""
-						if signatureResult.Exists() && signatureResult.String() != "" {
-							clientSignature = signatureResult.String()
-						}
+						// signatureResult := contentResult.Get("signature")
+						// clientSignature := ""
+						// if signatureResult.Exists() && signatureResult.String() != "" {
+						// 	clientSignature = signatureResult.String()
+						// }
 
 						// Always try cached signature first (more reliable than client-provided)
 						// Client may send stale or invalid signatures from different sessions
@@ -140,11 +140,11 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 							}
 						}
 
-						// Fallback to client signature only if cache miss and client signature is valid
-						if signature == "" && cache.HasValidSignature(clientSignature) {
-							signature = clientSignature
-							// log.Debugf("Using client-provided signature for thinking block")
-						}
+						// NOTE: We do NOT fallback to client signature anymore.
+						// Client signatures from Claude models are incompatible with Antigravity/Gemini API.
+						// When switching between models (e.g., Claude Opus -> Gemini Flash), the Claude
+						// signatures will cause "Corrupted thought signature" errors.
+						// If we have no cached signature, the thinking block will be skipped below.
 
 						// Store for subsequent tool_use in the same message
 						if cache.HasValidSignature(signature) {

internal/translator/antigravity/claude/antigravity_claude_request_test.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/cache"
 	"github.com/tidwall/gjson"
 )
 
@@ -75,28 +76,42 @@ func TestConvertClaudeRequestToAntigravity_RoleMapping(t *testing.T) {
 func TestConvertClaudeRequestToAntigravity_ThinkingBlocks(t *testing.T) {
 	// Valid signature must be at least 50 characters
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
+	thinkingText := "Let me think..."
+
+	// Pre-cache the signature (simulating a response from the same session)
+	// The session ID is derived from the first user message hash
+	// Since there's no user message in this test, we need to add one
 	inputJSON := []byte(`{
 		"model": "claude-sonnet-4-5-thinking",
 		"messages": [
+			{
+				"role": "user",
+				"content": [{"type": "text", "text": "Test user message"}]
+			},
 			{
 				"role": "assistant",
 				"content": [
-					{"type": "thinking", "thinking": "Let me think...", "signature": "` + validSignature + `"},
+					{"type": "thinking", "thinking": "` + thinkingText + `", "signature": "` + validSignature + `"},
 					{"type": "text", "text": "Answer"}
 				]
 			}
 		]
 	}`)
 
+	// Derive session ID and cache the signature
+	sessionID := deriveSessionID(inputJSON)
+	cache.CacheSignature(sessionID, thinkingText, validSignature)
+	defer cache.ClearSignatureCache(sessionID)
+
 	output := ConvertClaudeRequestToAntigravity("claude-sonnet-4-5-thinking", inputJSON, false)
 	outputStr := string(output)
 
-	// Check thinking block conversion
-	firstPart := gjson.Get(outputStr, "request.contents.0.parts.0")
+	// Check thinking block conversion (now in contents.1 due to user message)
+	firstPart := gjson.Get(outputStr, "request.contents.1.parts.0")
 	if !firstPart.Get("thought").Bool() {
 		t.Error("thinking block should have thought: true")
 	}
-	if firstPart.Get("text").String() != "Let me think..." {
+	if firstPart.Get("text").String() != thinkingText {
 		t.Error("thinking text mismatch")
 	}
 	if firstPart.Get("thoughtSignature").String() != validSignature {
@@ -227,13 +242,19 @@ func TestConvertClaudeRequestToAntigravity_ToolUse(t *testing.T) {
 
 func TestConvertClaudeRequestToAntigravity_ToolUse_WithSignature(t *testing.T) {
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
+	thinkingText := "Let me think..."
+
 	inputJSON := []byte(`{
 		"model": "claude-sonnet-4-5-thinking",
 		"messages": [
+			{
+				"role": "user",
+				"content": [{"type": "text", "text": "Test user message"}]
+			},
 			{
 				"role": "assistant",
 				"content": [
-					{"type": "thinking", "thinking": "Let me think...", "signature": "` + validSignature + `"},
+					{"type": "thinking", "thinking": "` + thinkingText + `", "signature": "` + validSignature + `"},
 					{
 						"type": "tool_use",
 						"id": "call_123",
@@ -245,11 +266,16 @@ func TestConvertClaudeRequestToAntigravity_ToolUse_WithSignature(t *testing.T) {
 		]
 	}`)
 
+	// Derive session ID and cache the signature
+	sessionID := deriveSessionID(inputJSON)
+	cache.CacheSignature(sessionID, thinkingText, validSignature)
+	defer cache.ClearSignatureCache(sessionID)
+
 	output := ConvertClaudeRequestToAntigravity("claude-sonnet-4-5-thinking", inputJSON, false)
 	outputStr := string(output)
 
-	// Check function call has the signature from the preceding thinking block
-	part := gjson.Get(outputStr, "request.contents.0.parts.1")
+	// Check function call has the signature from the preceding thinking block (now in contents.1)
+	part := gjson.Get(outputStr, "request.contents.1.parts.1")
 	if part.Get("functionCall.name").String() != "get_weather" {
 		t.Errorf("Expected functionCall, got %s", part.Raw)
 	}
@@ -261,24 +287,35 @@ func TestConvertClaudeRequestToAntigravity_ToolUse_WithSignature(t *testing.T) {
 func TestConvertClaudeRequestToAntigravity_ReorderThinking(t *testing.T) {
 	// Case: text block followed by thinking block -> should be reordered to thinking first
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
+	thinkingText := "Planning..."
+
 	inputJSON := []byte(`{
 		"model": "claude-sonnet-4-5-thinking",
 		"messages": [
+			{
+				"role": "user",
+				"content": [{"type": "text", "text": "Test user message"}]
+			},
 			{
 				"role": "assistant",
 				"content": [
 					{"type": "text", "text": "Here is the plan."},
-					{"type": "thinking", "thinking": "Planning...", "signature": "` + validSignature + `"}
+					{"type": "thinking", "thinking": "` + thinkingText + `", "signature": "` + validSignature + `"}
 				]
 			}
 		]
 	}`)
 
+	// Derive session ID and cache the signature
+	sessionID := deriveSessionID(inputJSON)
+	cache.CacheSignature(sessionID, thinkingText, validSignature)
+	defer cache.ClearSignatureCache(sessionID)
+
 	output := ConvertClaudeRequestToAntigravity("claude-sonnet-4-5-thinking", inputJSON, false)
 	outputStr := string(output)
 
-	// Verify order: Thinking block MUST be first
-	parts := gjson.Get(outputStr, "request.contents.0.parts").Array()
+	// Verify order: Thinking block MUST be first (now in contents.1 due to user message)
+	parts := gjson.Get(outputStr, "request.contents.1.parts").Array()
 	if len(parts) != 2 {
 		t.Fatalf("Expected 2 parts, got %d", len(parts))
 	}
@@ -460,6 +497,9 @@ func TestConvertClaudeRequestToAntigravity_TrailingUnsignedThinking_Removed(t *t
 
 func TestConvertClaudeRequestToAntigravity_TrailingSignedThinking_Kept(t *testing.T) {
 	// Last assistant message ends with signed thinking block - should be kept
+	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
+	thinkingText := "Valid thinking..."
+
 	inputJSON := []byte(`{
 		"model": "claude-sonnet-4-5-thinking",
 		"messages": [
@@ -471,12 +511,17 @@ func TestConvertClaudeRequestToAntigravity_TrailingSignedThinking_Kept(t *testin
 				"role": "assistant",
 				"content": [
 					{"type": "text", "text": "Here is my answer"},
-					{"type": "thinking", "thinking": "Valid thinking...", "signature": "abc123validSignature1234567890123456789012345678901234567890"}
+					{"type": "thinking", "thinking": "` + thinkingText + `", "signature": "` + validSignature + `"}
 				]
 			}
 		]
 	}`)
 
+	// Derive session ID and cache the signature
+	sessionID := deriveSessionID(inputJSON)
+	cache.CacheSignature(sessionID, thinkingText, validSignature)
+	defer cache.ClearSignatureCache(sessionID)
+
 	output := ConvertClaudeRequestToAntigravity("claude-sonnet-4-5-thinking", inputJSON, false)
 	outputStr := string(output)
 

test/thinking_conversion_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/thinking"
 	sdktranslator "github.com/router-for-me/CLIProxyAPI/v6/sdk/translator"
 	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
 )
 
 // thinkingTestCase represents a common test case structure for both suffix and body tests.
@@ -2707,8 +2708,11 @@ func runThinkingTests(t *testing.T, cases []thinkingTestCase) {
 				[]byte(tc.inputJSON),
 				true,
 			)
+			if applyTo == "claude" {
+				body, _ = sjson.SetBytes(body, "max_tokens", 200000)
+			}
 
-			body, err := thinking.ApplyThinking(body, tc.model, tc.from, applyTo)
+			body, err := thinking.ApplyThinking(body, tc.model, tc.from, applyTo, applyTo)
 
 			if tc.expectErr {
 				if err == nil {