diff --git a/internal/runtime/executor/aistudio_executor.go b/internal/runtime/executor/aistudio_executor.go
index 17c8170f..38c348f2 100644
--- a/internal/runtime/executor/aistudio_executor.go
+++ b/internal/runtime/executor/aistudio_executor.go
@@ -59,6 +59,7 @@ func (e *AIStudioExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth,
 	if err != nil {
 		return resp, err
 	}
+
 	endpoint := e.buildEndpoint(req.Model, body.action, opts.Alt)
 	wsReq := &wsrelay.HTTPRequest{
 		Method:  http.MethodPost,
@@ -113,6 +114,7 @@ func (e *AIStudioExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth
 	if err != nil {
 		return nil, err
 	}
+
 	endpoint := e.buildEndpoint(req.Model, body.action, opts.Alt)
 	wsReq := &wsrelay.HTTPRequest{
 		Method:  http.MethodPost,
diff --git a/internal/runtime/executor/antigravity_executor.go b/internal/runtime/executor/antigravity_executor.go
index 9ade4fbb..950141f0 100644
--- a/internal/runtime/executor/antigravity_executor.go
+++ b/internal/runtime/executor/antigravity_executor.go
@@ -76,11 +76,7 @@ func (e *AntigravityExecutor) PrepareRequest(_ *http.Request, _ *cliproxyauth.Au
 
 // Execute performs a non-streaming request to the Antigravity API.
 func (e *AntigravityExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (resp cliproxyexecutor.Response, err error) {
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	isClaude := strings.Contains(strings.ToLower(upstreamModel), "claude")
+	isClaude := strings.Contains(strings.ToLower(req.Model), "claude")
 	if isClaude {
 		return e.executeClaudeNonStream(ctx, auth, req, opts)
 	}
@@ -114,7 +110,7 @@ func (e *AntigravityExecutor) Execute(ctx context.Context, auth *cliproxyauth.Au
 	var lastErr error
 
 	for idx, baseURL := range baseURLs {
-		httpReq, errReq := e.buildRequest(ctx, auth, token, upstreamModel, translated, false, opts.Alt, baseURL)
+		httpReq, errReq := e.buildRequest(ctx, auth, token, req.Model, translated, false, opts.Alt, baseURL)
 		if errReq != nil {
 			err = errReq
 			return resp, err
@@ -195,11 +191,6 @@ func (e *AntigravityExecutor) executeClaudeNonStream(ctx context.Context, auth *
 	to := sdktranslator.FromString("antigravity")
 	translated := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-
 	translated = applyThinkingMetadataCLI(translated, req.Metadata, req.Model)
 	translated = util.ApplyGemini3ThinkingLevelFromMetadataCLI(req.Model, req.Metadata, translated)
 	translated = util.ApplyDefaultThinkingIfNeededCLI(req.Model, translated)
@@ -214,7 +205,7 @@ func (e *AntigravityExecutor) executeClaudeNonStream(ctx context.Context, auth *
 	var lastErr error
 
 	for idx, baseURL := range baseURLs {
-		httpReq, errReq := e.buildRequest(ctx, auth, token, upstreamModel, translated, true, opts.Alt, baseURL)
+		httpReq, errReq := e.buildRequest(ctx, auth, token, req.Model, translated, true, opts.Alt, baseURL)
 		if errReq != nil {
 			err = errReq
 			return resp, err
@@ -530,16 +521,12 @@ func (e *AntigravityExecutor) ExecuteStream(ctx context.Context, auth *cliproxya
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
+	isClaude := strings.Contains(strings.ToLower(req.Model), "claude")
+
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("antigravity")
 	translated := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	isClaude := strings.Contains(strings.ToLower(upstreamModel), "claude")
-
 	translated = applyThinkingMetadataCLI(translated, req.Metadata, req.Model)
 	translated = util.ApplyGemini3ThinkingLevelFromMetadataCLI(req.Model, req.Metadata, translated)
 	translated = util.ApplyDefaultThinkingIfNeededCLI(req.Model, translated)
@@ -554,7 +541,7 @@ func (e *AntigravityExecutor) ExecuteStream(ctx context.Context, auth *cliproxya
 	var lastErr error
 
 	for idx, baseURL := range baseURLs {
-		httpReq, errReq := e.buildRequest(ctx, auth, token, upstreamModel, translated, true, opts.Alt, baseURL)
+		httpReq, errReq := e.buildRequest(ctx, auth, token, req.Model, translated, true, opts.Alt, baseURL)
 		if errReq != nil {
 			err = errReq
 			return nil, err
@@ -692,11 +679,7 @@ func (e *AntigravityExecutor) CountTokens(ctx context.Context, auth *cliproxyaut
 	to := sdktranslator.FromString("antigravity")
 	respCtx := context.WithValue(ctx, "alt", opts.Alt)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	isClaude := strings.Contains(strings.ToLower(upstreamModel), "claude")
+	isClaude := strings.Contains(strings.ToLower(req.Model), "claude")
 
 	baseURLs := antigravityBaseURLFallbackOrder(auth)
 	httpClient := newProxyAwareHTTPClient(ctx, e.cfg, auth, 0)
diff --git a/internal/runtime/executor/claude_executor.go b/internal/runtime/executor/claude_executor.go
index 2fbb235b..f74dc1e0 100644
--- a/internal/runtime/executor/claude_executor.go
+++ b/internal/runtime/executor/claude_executor.go
@@ -49,36 +49,29 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	}
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
+	}
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("claude")
 	// Use streaming translation to preserve function calling, except for claude.
 	stream := from != to
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), stream)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
-	}
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), stream)
+	body, _ = sjson.SetBytes(body, "model", model)
 	// Inject thinking config based on model metadata for thinking variants
-	body = e.injectThinkingConfig(req.Model, req.Metadata, body)
+	body = e.injectThinkingConfig(model, req.Metadata, body)
 
-	if !strings.HasPrefix(upstreamModel, "claude-3-5-haiku") {
+	if !strings.HasPrefix(model, "claude-3-5-haiku") {
 		body = checkSystemInstructions(body)
 	}
-	body = applyPayloadConfig(e.cfg, req.Model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
 
 	// 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(req.Model, body)
+	body = ensureMaxTokensForThinking(model, body)
 
 	// Extract betas from body and convert to header
 	var extraBetas []string
@@ -170,29 +163,22 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	defer reporter.trackFailure(ctx, &err)
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("claude")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
 	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
-	}
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), true)
+	body, _ = sjson.SetBytes(body, "model", model)
 	// Inject thinking config based on model metadata for thinking variants
-	body = e.injectThinkingConfig(req.Model, req.Metadata, body)
+	body = e.injectThinkingConfig(model, req.Metadata, body)
 	body = checkSystemInstructions(body)
-	body = applyPayloadConfig(e.cfg, req.Model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
 
 	// 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(req.Model, body)
+	body = ensureMaxTokensForThinking(model, body)
 
 	// Extract betas from body and convert to header
 	var extraBetas []string
@@ -316,21 +302,14 @@ func (e *ClaudeExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Aut
 	to := sdktranslator.FromString("claude")
 	// Use streaming translation to preserve function calling, except for claude.
 	stream := from != to
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), stream)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
 	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
-	}
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), stream)
+	body, _ = sjson.SetBytes(body, "model", model)
 
-	if !strings.HasPrefix(upstreamModel, "claude-3-5-haiku") {
+	if !strings.HasPrefix(model, "claude-3-5-haiku") {
 		body = checkSystemInstructions(body)
 	}
 
diff --git a/internal/runtime/executor/codex_executor.go b/internal/runtime/executor/codex_executor.go
index 310988c1..98678c4d 100644
--- a/internal/runtime/executor/codex_executor.go
+++ b/internal/runtime/executor/codex_executor.go
@@ -49,28 +49,21 @@ func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
 	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("codex")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
-	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning.effort", false)
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
+	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
+	body = NormalizeThinkingConfig(body, model, false)
+	if errValidate := ValidateThinkingConfig(body, model); errValidate != nil {
 		return resp, errValidate
 	}
-	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body = applyPayloadConfig(e.cfg, model, body)
+	body, _ = sjson.SetBytes(body, "model", model)
 	body, _ = sjson.SetBytes(body, "stream", true)
 	body, _ = sjson.DeleteBytes(body, "previous_response_id")
 
@@ -156,30 +149,23 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
 	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("codex")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), true)
 
-	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning.effort", false)
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
+	body = NormalizeThinkingConfig(body, model, false)
+	if errValidate := ValidateThinkingConfig(body, model); errValidate != nil {
 		return nil, errValidate
 	}
-	body = applyPayloadConfig(e.cfg, req.Model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
 	body, _ = sjson.DeleteBytes(body, "previous_response_id")
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body, _ = sjson.SetBytes(body, "model", model)
 
 	url := strings.TrimSuffix(baseURL, "/") + "/responses"
 	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
@@ -266,30 +252,21 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 }
 
 func (e *CodexExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (cliproxyexecutor.Response, error) {
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel == "" {
-		upstreamModel = req.Model
-	}
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
 	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("codex")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
 
-	modelForCounting := upstreamModel
-
-	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning.effort", false)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
+	body, _ = sjson.SetBytes(body, "model", model)
 	body, _ = sjson.DeleteBytes(body, "previous_response_id")
 	body, _ = sjson.SetBytes(body, "stream", false)
 
-	enc, err := tokenizerForCodexModel(modelForCounting)
+	enc, err := tokenizerForCodexModel(model)
 	if err != nil {
 		return cliproxyexecutor.Response{}, fmt.Errorf("codex executor: tokenizer init failed: %w", err)
 	}
diff --git a/internal/runtime/executor/gemini_cli_executor.go b/internal/runtime/executor/gemini_cli_executor.go
index b171041a..a3b75839 100644
--- a/internal/runtime/executor/gemini_cli_executor.go
+++ b/internal/runtime/executor/gemini_cli_executor.go
@@ -318,7 +318,7 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 
 		out := make(chan cliproxyexecutor.StreamChunk)
 		stream = out
-		go func(resp *http.Response, reqBody []byte, attempt string) {
+		go func(resp *http.Response, reqBody []byte, attemptModel string) {
 			defer close(out)
 			defer func() {
 				if errClose := resp.Body.Close(); errClose != nil {
@@ -336,14 +336,14 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 						reporter.publish(ctx, detail)
 					}
 					if bytes.HasPrefix(line, dataTag) {
-						segments := sdktranslator.TranslateStream(respCtx, to, from, attempt, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone(line), &param)
+						segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone(line), &param)
 						for i := range segments {
 							out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 						}
 					}
 				}
 
-				segments := sdktranslator.TranslateStream(respCtx, to, from, attempt, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
+				segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
 				for i := range segments {
 					out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 				}
@@ -365,12 +365,12 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 			appendAPIResponseChunk(ctx, e.cfg, data)
 			reporter.publish(ctx, parseGeminiCLIUsage(data))
 			var param any
-			segments := sdktranslator.TranslateStream(respCtx, to, from, attempt, bytes.Clone(opts.OriginalRequest), reqBody, data, &param)
+			segments := sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, data, &param)
 			for i := range segments {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 			}
 
-			segments = sdktranslator.TranslateStream(respCtx, to, from, attempt, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
+			segments = sdktranslator.TranslateStream(respCtx, to, from, attemptModel, bytes.Clone(opts.OriginalRequest), reqBody, bytes.Clone([]byte("[DONE]")), &param)
 			for i := range segments {
 				out <- cliproxyexecutor.StreamChunk{Payload: []byte(segments[i])}
 			}
@@ -417,6 +417,8 @@ func (e *GeminiCLIExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.
 	var lastStatus int
 	var lastBody []byte
 
+	// The loop variable attemptModel is only used as the concrete model id sent to the upstream
+	// Gemini CLI endpoint when iterating fallback variants.
 	for _, attemptModel := range models {
 		payload := sdktranslator.TranslateRequest(from, to, attemptModel, bytes.Clone(req.Payload), false)
 		payload = applyThinkingMetadataCLI(payload, req.Metadata, req.Model)
@@ -425,7 +427,7 @@ func (e *GeminiCLIExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.
 		payload = deleteJSONField(payload, "model")
 		payload = deleteJSONField(payload, "request.safetySettings")
 		payload = util.StripThinkingConfigIfUnsupported(req.Model, payload)
-		payload = fixGeminiCLIImageAspectRatio(attemptModel, payload)
+		payload = fixGeminiCLIImageAspectRatio(req.Model, payload)
 
 		tok, errTok := tokenSource.Token()
 		if errTok != nil {
diff --git a/internal/runtime/executor/gemini_executor.go b/internal/runtime/executor/gemini_executor.go
index da57150d..d69044b8 100644
--- a/internal/runtime/executor/gemini_executor.go
+++ b/internal/runtime/executor/gemini_executor.go
@@ -77,26 +77,22 @@ func (e *GeminiExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(model, auth); override != "" {
+		model = override
 	}
 
 	// Official Gemini API via API key or OAuth bearer
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
-	body = ApplyThinkingMetadata(body, req.Metadata, req.Model)
-	body = util.ApplyDefaultThinkingIfNeeded(req.Model, body)
-	body = util.NormalizeGeminiThinkingBudget(req.Model, body)
-	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
-	body = fixGeminiImageAspectRatio(req.Model, body)
-	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
+	body = ApplyThinkingMetadata(body, req.Metadata, model)
+	body = util.ApplyDefaultThinkingIfNeeded(model, body)
+	body = util.NormalizeGeminiThinkingBudget(model, body)
+	body = util.StripThinkingConfigIfUnsupported(model, body)
+	body = fixGeminiImageAspectRatio(model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
+	body, _ = sjson.SetBytes(body, "model", model)
 
 	action := "generateContent"
 	if req.Metadata != nil {
@@ -105,7 +101,7 @@ func (e *GeminiExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 		}
 	}
 	baseURL := resolveGeminiBaseURL(auth)
-	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, upstreamModel, action)
+	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, model, action)
 	if opts.Alt != "" && action != "countTokens" {
 		url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
 	}
@@ -180,28 +176,24 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(model, auth); override != "" {
+		model = override
 	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
-	body = ApplyThinkingMetadata(body, req.Metadata, req.Model)
-	body = util.ApplyDefaultThinkingIfNeeded(req.Model, body)
-	body = util.NormalizeGeminiThinkingBudget(req.Model, body)
-	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
-	body = fixGeminiImageAspectRatio(req.Model, body)
-	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), true)
+	body = ApplyThinkingMetadata(body, req.Metadata, model)
+	body = util.ApplyDefaultThinkingIfNeeded(model, body)
+	body = util.NormalizeGeminiThinkingBudget(model, body)
+	body = util.StripThinkingConfigIfUnsupported(model, body)
+	body = fixGeminiImageAspectRatio(model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
+	body, _ = sjson.SetBytes(body, "model", model)
 
 	baseURL := resolveGeminiBaseURL(auth)
-	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, upstreamModel, "streamGenerateContent")
+	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, model, "streamGenerateContent")
 	if opts.Alt == "" {
 		url = url + "?alt=sse"
 	} else {
@@ -301,29 +293,25 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 func (e *GeminiExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (cliproxyexecutor.Response, error) {
 	apiKey, bearer := geminiCreds(auth)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if modelOverride := e.resolveUpstreamModel(upstreamModel, auth); modelOverride != "" {
-		upstreamModel = modelOverride
-	} else if !strings.EqualFold(upstreamModel, req.Model) {
-		if modelOverride := e.resolveUpstreamModel(req.Model, auth); modelOverride != "" {
-			upstreamModel = modelOverride
-		}
+	model := req.Model
+	if override := e.resolveUpstreamModel(model, auth); override != "" {
+		model = override
 	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	translatedReq := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
-	translatedReq = ApplyThinkingMetadata(translatedReq, req.Metadata, req.Model)
-	translatedReq = util.StripThinkingConfigIfUnsupported(req.Model, translatedReq)
-	translatedReq = fixGeminiImageAspectRatio(req.Model, translatedReq)
+	translatedReq := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
+	translatedReq = ApplyThinkingMetadata(translatedReq, req.Metadata, model)
+	translatedReq = util.StripThinkingConfigIfUnsupported(model, translatedReq)
+	translatedReq = fixGeminiImageAspectRatio(model, translatedReq)
 	respCtx := context.WithValue(ctx, "alt", opts.Alt)
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "tools")
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "generationConfig")
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "safetySettings")
-	translatedReq, _ = sjson.SetBytes(translatedReq, "model", upstreamModel)
+	translatedReq, _ = sjson.SetBytes(translatedReq, "model", model)
 
 	baseURL := resolveGeminiBaseURL(auth)
-	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, upstreamModel, "countTokens")
+	url := fmt.Sprintf("%s/%s/models/%s:%s", baseURL, glAPIVersion, model, "countTokens")
 
 	requestBody := bytes.NewReader(translatedReq)
 
diff --git a/internal/runtime/executor/gemini_vertex_executor.go b/internal/runtime/executor/gemini_vertex_executor.go
index df8ee506..f8f4a63a 100644
--- a/internal/runtime/executor/gemini_vertex_executor.go
+++ b/internal/runtime/executor/gemini_vertex_executor.go
@@ -120,8 +120,6 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
@@ -137,7 +135,7 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
 	body = fixGeminiImageAspectRatio(req.Model, body)
 	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body, _ = sjson.SetBytes(body, "model", req.Model)
 
 	action := "generateContent"
 	if req.Metadata != nil {
@@ -146,7 +144,7 @@ func (e *GeminiVertexExecutor) executeWithServiceAccount(ctx context.Context, au
 		}
 	}
 	baseURL := vertexBaseURL(location)
-	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, upstreamModel, action)
+	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, req.Model, action)
 	if opts.Alt != "" && action != "countTokens" {
 		url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
 	}
@@ -220,24 +218,27 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
+	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
-	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(req.Model, req.Metadata); ok && util.ModelSupportsThinking(req.Model) {
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
+	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(model, req.Metadata); ok && util.ModelSupportsThinking(model) {
 		if budgetOverride != nil {
-			norm := util.NormalizeThinkingBudget(req.Model, *budgetOverride)
+			norm := util.NormalizeThinkingBudget(model, *budgetOverride)
 			budgetOverride = &norm
 		}
 		body = util.ApplyGeminiThinkingConfig(body, budgetOverride, includeOverride)
 	}
-	body = util.ApplyDefaultThinkingIfNeeded(req.Model, body)
-	body = util.NormalizeGeminiThinkingBudget(req.Model, body)
-	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
-	body = fixGeminiImageAspectRatio(req.Model, body)
-	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body = util.ApplyDefaultThinkingIfNeeded(model, body)
+	body = util.NormalizeGeminiThinkingBudget(model, body)
+	body = util.StripThinkingConfigIfUnsupported(model, body)
+	body = fixGeminiImageAspectRatio(model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
+	body, _ = sjson.SetBytes(body, "model", model)
 
 	action := "generateContent"
 	if req.Metadata != nil {
@@ -250,7 +251,7 @@ func (e *GeminiVertexExecutor) executeWithAPIKey(ctx context.Context, auth *clip
 	if baseURL == "" {
 		baseURL = "https://generativelanguage.googleapis.com"
 	}
-	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, upstreamModel, action)
+	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, model, action)
 	if opts.Alt != "" && action != "countTokens" {
 		url = url + fmt.Sprintf("?$alt=%s", opts.Alt)
 	}
@@ -321,8 +322,6 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
@@ -338,10 +337,10 @@ func (e *GeminiVertexExecutor) executeStreamWithServiceAccount(ctx context.Conte
 	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
 	body = fixGeminiImageAspectRatio(req.Model, body)
 	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body, _ = sjson.SetBytes(body, "model", req.Model)
 
 	baseURL := vertexBaseURL(location)
-	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, upstreamModel, "streamGenerateContent")
+	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, req.Model, "streamGenerateContent")
 	if opts.Alt == "" {
 		url = url + "?alt=sse"
 	} else {
@@ -438,30 +437,33 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
 	defer reporter.trackFailure(ctx, &err)
 
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
+	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
-	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(req.Model, req.Metadata); ok && util.ModelSupportsThinking(req.Model) {
+	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), true)
+	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(model, req.Metadata); ok && util.ModelSupportsThinking(model) {
 		if budgetOverride != nil {
-			norm := util.NormalizeThinkingBudget(req.Model, *budgetOverride)
+			norm := util.NormalizeThinkingBudget(model, *budgetOverride)
 			budgetOverride = &norm
 		}
 		body = util.ApplyGeminiThinkingConfig(body, budgetOverride, includeOverride)
 	}
-	body = util.ApplyDefaultThinkingIfNeeded(req.Model, body)
-	body = util.NormalizeGeminiThinkingBudget(req.Model, body)
-	body = util.StripThinkingConfigIfUnsupported(req.Model, body)
-	body = fixGeminiImageAspectRatio(req.Model, body)
-	body = applyPayloadConfig(e.cfg, req.Model, body)
-	body, _ = sjson.SetBytes(body, "model", upstreamModel)
+	body = util.ApplyDefaultThinkingIfNeeded(model, body)
+	body = util.NormalizeGeminiThinkingBudget(model, body)
+	body = util.StripThinkingConfigIfUnsupported(model, body)
+	body = fixGeminiImageAspectRatio(model, body)
+	body = applyPayloadConfig(e.cfg, model, body)
+	body, _ = sjson.SetBytes(body, "model", model)
 
 	// 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, upstreamModel, "streamGenerateContent")
+	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, model, "streamGenerateContent")
 	if opts.Alt == "" {
 		url = url + "?alt=sse"
 	} else {
@@ -552,8 +554,6 @@ func (e *GeminiVertexExecutor) executeStreamWithAPIKey(ctx context.Context, auth
 
 // countTokensWithServiceAccount counts tokens using service account credentials.
 func (e *GeminiVertexExecutor) countTokensWithServiceAccount(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options, projectID, location string, saJSON []byte) (cliproxyexecutor.Response, error) {
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
 	translatedReq := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
@@ -566,14 +566,14 @@ func (e *GeminiVertexExecutor) countTokensWithServiceAccount(ctx context.Context
 	}
 	translatedReq = util.StripThinkingConfigIfUnsupported(req.Model, translatedReq)
 	translatedReq = fixGeminiImageAspectRatio(req.Model, translatedReq)
-	translatedReq, _ = sjson.SetBytes(translatedReq, "model", upstreamModel)
+	translatedReq, _ = sjson.SetBytes(translatedReq, "model", req.Model)
 	respCtx := context.WithValue(ctx, "alt", opts.Alt)
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "tools")
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "generationConfig")
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "safetySettings")
 
 	baseURL := vertexBaseURL(location)
-	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, upstreamModel, "countTokens")
+	url := fmt.Sprintf("%s/%s/projects/%s/locations/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, projectID, location, req.Model, "countTokens")
 
 	httpReq, errNewReq := http.NewRequestWithContext(respCtx, http.MethodPost, url, bytes.NewReader(translatedReq))
 	if errNewReq != nil {
@@ -641,21 +641,24 @@ func (e *GeminiVertexExecutor) countTokensWithServiceAccount(ctx context.Context
 
 // countTokensWithAPIKey handles token counting using API key credentials.
 func (e *GeminiVertexExecutor) countTokensWithAPIKey(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options, apiKey, baseURL string) (cliproxyexecutor.Response, error) {
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
+	model := req.Model
+	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
+		model = override
+	}
 
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("gemini")
-	translatedReq := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
-	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(req.Model, req.Metadata); ok && util.ModelSupportsThinking(req.Model) {
+	translatedReq := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
+	if budgetOverride, includeOverride, ok := util.ResolveThinkingConfigFromMetadata(model, req.Metadata); ok && util.ModelSupportsThinking(model) {
 		if budgetOverride != nil {
-			norm := util.NormalizeThinkingBudget(req.Model, *budgetOverride)
+			norm := util.NormalizeThinkingBudget(model, *budgetOverride)
 			budgetOverride = &norm
 		}
 		translatedReq = util.ApplyGeminiThinkingConfig(translatedReq, budgetOverride, includeOverride)
 	}
-	translatedReq = util.StripThinkingConfigIfUnsupported(req.Model, translatedReq)
-	translatedReq = fixGeminiImageAspectRatio(req.Model, translatedReq)
-	translatedReq, _ = sjson.SetBytes(translatedReq, "model", upstreamModel)
+	translatedReq = util.StripThinkingConfigIfUnsupported(model, translatedReq)
+	translatedReq = fixGeminiImageAspectRatio(model, translatedReq)
+	translatedReq, _ = sjson.SetBytes(translatedReq, "model", model)
 	respCtx := context.WithValue(ctx, "alt", opts.Alt)
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "tools")
 	translatedReq, _ = sjson.DeleteBytes(translatedReq, "generationConfig")
@@ -665,7 +668,7 @@ func (e *GeminiVertexExecutor) countTokensWithAPIKey(ctx context.Context, auth *
 	if baseURL == "" {
 		baseURL = "https://generativelanguage.googleapis.com"
 	}
-	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, req.Model, "countTokens")
+	url := fmt.Sprintf("%s/%s/publishers/google/models/%s:%s", baseURL, vertexAPIVersion, model, "countTokens")
 
 	httpReq, errNewReq := http.NewRequestWithContext(respCtx, http.MethodPost, url, bytes.NewReader(translatedReq))
 	if errNewReq != nil {
@@ -808,3 +811,90 @@ func vertexAccessToken(ctx context.Context, cfg *config.Config, auth *cliproxyau
 	}
 	return tok.AccessToken, nil
 }
+
+// resolveUpstreamModel resolves the upstream model name from vertex-api-key configuration.
+// It matches the requested model alias against configured models and returns the actual upstream name.
+func (e *GeminiVertexExecutor) resolveUpstreamModel(alias string, auth *cliproxyauth.Auth) string {
+	trimmed := strings.TrimSpace(alias)
+	if trimmed == "" {
+		return ""
+	}
+
+	entry := e.resolveVertexConfig(auth)
+	if entry == nil {
+		return ""
+	}
+
+	normalizedModel, metadata := util.NormalizeThinkingModel(trimmed)
+
+	// Candidate names to match against configured aliases/names.
+	candidates := []string{strings.TrimSpace(normalizedModel)}
+	if !strings.EqualFold(normalizedModel, trimmed) {
+		candidates = append(candidates, trimmed)
+	}
+	if original := util.ResolveOriginalModel(normalizedModel, metadata); original != "" && !strings.EqualFold(original, normalizedModel) {
+		candidates = append(candidates, original)
+	}
+
+	for i := range entry.Models {
+		model := entry.Models[i]
+		name := strings.TrimSpace(model.Name)
+		modelAlias := strings.TrimSpace(model.Alias)
+
+		for _, candidate := range candidates {
+			if candidate == "" {
+				continue
+			}
+			if modelAlias != "" && strings.EqualFold(modelAlias, candidate) {
+				if name != "" {
+					return name
+				}
+				return candidate
+			}
+			if name != "" && strings.EqualFold(name, candidate) {
+				return name
+			}
+		}
+	}
+	return ""
+}
+
+// resolveVertexConfig finds the matching vertex-api-key configuration entry for the given auth.
+func (e *GeminiVertexExecutor) resolveVertexConfig(auth *cliproxyauth.Auth) *config.VertexCompatKey {
+	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.VertexCompatAPIKey {
+		entry := &e.cfg.VertexCompatAPIKey[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.VertexCompatAPIKey {
+			entry := &e.cfg.VertexCompatAPIKey[i]
+			if strings.EqualFold(strings.TrimSpace(entry.APIKey), attrKey) {
+				return entry
+			}
+		}
+	}
+	return nil
+}
diff --git a/internal/runtime/executor/iflow_executor.go b/internal/runtime/executor/iflow_executor.go
index 124a984e..49fd4eb7 100644
--- a/internal/runtime/executor/iflow_executor.go
+++ b/internal/runtime/executor/iflow_executor.go
@@ -58,12 +58,9 @@ func (e *IFlowExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	to := sdktranslator.FromString("openai")
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
 	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning_effort", false)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" {
-		body, _ = sjson.SetBytes(body, "model", upstreamModel)
-	}
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body, _ = sjson.SetBytes(body, "model", req.Model)
+	body = NormalizeThinkingConfig(body, req.Model, false)
+	if errValidate := ValidateThinkingConfig(body, req.Model); errValidate != nil {
 		return resp, errValidate
 	}
 	body = applyIFlowThinkingConfig(body)
@@ -151,12 +148,9 @@ func (e *IFlowExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
 
 	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning_effort", false)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" {
-		body, _ = sjson.SetBytes(body, "model", upstreamModel)
-	}
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body, _ = sjson.SetBytes(body, "model", req.Model)
+	body = NormalizeThinkingConfig(body, req.Model, false)
+	if errValidate := ValidateThinkingConfig(body, req.Model); errValidate != nil {
 		return nil, errValidate
 	}
 	body = applyIFlowThinkingConfig(body)
diff --git a/internal/runtime/executor/openai_compat_executor.go b/internal/runtime/executor/openai_compat_executor.go
index 1c57c9b7..81fc31a1 100644
--- a/internal/runtime/executor/openai_compat_executor.go
+++ b/internal/runtime/executor/openai_compat_executor.go
@@ -61,12 +61,8 @@ func (e *OpenAICompatExecutor) Execute(ctx context.Context, auth *cliproxyauth.A
 	translated = applyPayloadConfigWithRoot(e.cfg, req.Model, to.String(), "", translated)
 	allowCompat := e.allowCompatReasoningEffort(req.Model, auth)
 	translated = ApplyReasoningEffortMetadata(translated, req.Metadata, req.Model, "reasoning_effort", allowCompat)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" && modelOverride == "" {
-		translated, _ = sjson.SetBytes(translated, "model", upstreamModel)
-	}
-	translated = NormalizeThinkingConfig(translated, upstreamModel, allowCompat)
-	if errValidate := ValidateThinkingConfig(translated, upstreamModel); errValidate != nil {
+	translated = NormalizeThinkingConfig(translated, req.Model, allowCompat)
+	if errValidate := ValidateThinkingConfig(translated, req.Model); errValidate != nil {
 		return resp, errValidate
 	}
 
@@ -157,12 +153,8 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 	translated = applyPayloadConfigWithRoot(e.cfg, req.Model, to.String(), "", translated)
 	allowCompat := e.allowCompatReasoningEffort(req.Model, auth)
 	translated = ApplyReasoningEffortMetadata(translated, req.Metadata, req.Model, "reasoning_effort", allowCompat)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" && modelOverride == "" {
-		translated, _ = sjson.SetBytes(translated, "model", upstreamModel)
-	}
-	translated = NormalizeThinkingConfig(translated, upstreamModel, allowCompat)
-	if errValidate := ValidateThinkingConfig(translated, upstreamModel); errValidate != nil {
+	translated = NormalizeThinkingConfig(translated, req.Model, allowCompat)
+	if errValidate := ValidateThinkingConfig(translated, req.Model); errValidate != nil {
 		return nil, errValidate
 	}
 
diff --git a/internal/runtime/executor/qwen_executor.go b/internal/runtime/executor/qwen_executor.go
index 1d4ef52d..ff6fa414 100644
--- a/internal/runtime/executor/qwen_executor.go
+++ b/internal/runtime/executor/qwen_executor.go
@@ -12,7 +12,6 @@ import (
 
 	qwenauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/qwen"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
-	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
 	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/executor"
 	sdktranslator "github.com/router-for-me/CLIProxyAPI/v6/sdk/translator"
@@ -52,12 +51,9 @@ func (e *QwenExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req
 	to := sdktranslator.FromString("openai")
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)
 	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning_effort", false)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" {
-		body, _ = sjson.SetBytes(body, "model", upstreamModel)
-	}
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body, _ = sjson.SetBytes(body, "model", req.Model)
+	body = NormalizeThinkingConfig(body, req.Model, false)
+	if errValidate := ValidateThinkingConfig(body, req.Model); errValidate != nil {
 		return resp, errValidate
 	}
 	body = applyPayloadConfig(e.cfg, req.Model, body)
@@ -132,12 +128,9 @@ func (e *QwenExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Aut
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
 
 	body = ApplyReasoningEffortMetadata(body, req.Metadata, req.Model, "reasoning_effort", false)
-	upstreamModel := util.ResolveOriginalModel(req.Model, req.Metadata)
-	if upstreamModel != "" {
-		body, _ = sjson.SetBytes(body, "model", upstreamModel)
-	}
-	body = NormalizeThinkingConfig(body, upstreamModel, false)
-	if errValidate := ValidateThinkingConfig(body, upstreamModel); errValidate != nil {
+	body, _ = sjson.SetBytes(body, "model", req.Model)
+	body = NormalizeThinkingConfig(body, req.Model, false)
+	if errValidate := ValidateThinkingConfig(body, req.Model); errValidate != nil {
 		return nil, errValidate
 	}
 	toolsResult := gjson.GetBytes(body, "tools")
diff --git a/sdk/cliproxy/auth/conductor.go b/sdk/cliproxy/auth/conductor.go
index a6eaf3c5..c480d965 100644
--- a/sdk/cliproxy/auth/conductor.go
+++ b/sdk/cliproxy/auth/conductor.go
@@ -413,7 +413,7 @@ func (m *Manager) executeWithProvider(ctx context.Context, provider string, req
 		}
 		execReq := req
 		execReq.Model, execReq.Metadata = rewriteModelForAuth(routeModel, req.Metadata, auth)
-		execReq.Metadata = m.applyOAuthModelMappingMetadata(auth, execReq.Model, execReq.Metadata)
+		execReq.Model, execReq.Metadata = m.applyOAuthModelMapping(auth, execReq.Model, execReq.Metadata)
 		resp, errExec := executor.Execute(execCtx, auth, execReq, opts)
 		result := Result{AuthID: auth.ID, Provider: provider, Model: routeModel, Success: errExec == nil}
 		if errExec != nil {
@@ -475,7 +475,7 @@ func (m *Manager) executeCountWithProvider(ctx context.Context, provider string,
 		}
 		execReq := req
 		execReq.Model, execReq.Metadata = rewriteModelForAuth(routeModel, req.Metadata, auth)
-		execReq.Metadata = m.applyOAuthModelMappingMetadata(auth, execReq.Model, execReq.Metadata)
+		execReq.Model, execReq.Metadata = m.applyOAuthModelMapping(auth, execReq.Model, execReq.Metadata)
 		resp, errExec := executor.CountTokens(execCtx, auth, execReq, opts)
 		result := Result{AuthID: auth.ID, Provider: provider, Model: routeModel, Success: errExec == nil}
 		if errExec != nil {
@@ -537,7 +537,7 @@ func (m *Manager) executeStreamWithProvider(ctx context.Context, provider string
 		}
 		execReq := req
 		execReq.Model, execReq.Metadata = rewriteModelForAuth(routeModel, req.Metadata, auth)
-		execReq.Metadata = m.applyOAuthModelMappingMetadata(auth, execReq.Model, execReq.Metadata)
+		execReq.Model, execReq.Metadata = m.applyOAuthModelMapping(auth, execReq.Model, execReq.Metadata)
 		chunks, errStream := executor.ExecuteStream(execCtx, auth, execReq, opts)
 		if errStream != nil {
 			rerr := &Error{Message: errStream.Error()}
diff --git a/sdk/cliproxy/auth/model_name_mappings.go b/sdk/cliproxy/auth/model_name_mappings.go
index 483cb9c9..f1b31aa5 100644
--- a/sdk/cliproxy/auth/model_name_mappings.go
+++ b/sdk/cliproxy/auth/model_name_mappings.go
@@ -65,17 +65,14 @@ func (m *Manager) SetOAuthModelMappings(mappings map[string][]internalconfig.Mod
 	m.modelNameMappings.Store(table)
 }
 
-func (m *Manager) applyOAuthModelMappingMetadata(auth *Auth, requestedModel string, metadata map[string]any) map[string]any {
-	original := m.resolveOAuthUpstreamModel(auth, requestedModel)
-	if original == "" {
-		return metadata
-	}
-	if metadata != nil {
-		if v, ok := metadata[util.ModelMappingOriginalModelMetadataKey]; ok {
-			if s, okStr := v.(string); okStr && strings.EqualFold(s, original) {
-				return metadata
-			}
-		}
+// applyOAuthModelMapping resolves the upstream model from OAuth model mappings
+// and returns the resolved model along with updated metadata. If a mapping exists,
+// the returned model is the upstream model and metadata contains the original
+// requested model for response translation.
+func (m *Manager) applyOAuthModelMapping(auth *Auth, requestedModel string, metadata map[string]any) (string, map[string]any) {
+	upstreamModel := m.resolveOAuthUpstreamModel(auth, requestedModel)
+	if upstreamModel == "" {
+		return requestedModel, metadata
 	}
 	out := make(map[string]any, 1)
 	if len(metadata) > 0 {
@@ -84,8 +81,8 @@ func (m *Manager) applyOAuthModelMappingMetadata(auth *Auth, requestedModel stri
 			out[k] = v
 		}
 	}
-	out[util.ModelMappingOriginalModelMetadataKey] = original
-	return out
+	out[util.ModelMappingOriginalModelMetadataKey] = upstreamModel
+	return upstreamModel, out
 }
 
 func (m *Manager) resolveOAuthUpstreamModel(auth *Auth, requestedModel string) string {