Merge pull request #2268 from sususu98/fix/sanitize-tool-names

fix(translator): sanitize tool names for Gemini function_declarations compatibility

internal/translator/antigravity/claude/antigravity_claude_request.go

@@ -171,7 +171,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 						// NOTE: Do NOT inject dummy thinking blocks here.
 						// Antigravity API validates signatures, so dummy values are rejected.
 
-						functionName := contentResult.Get("name").String()
+						functionName := util.SanitizeFunctionName(contentResult.Get("name").String())
 						argsResult := contentResult.Get("input")
 						functionID := contentResult.Get("id").String()
 
@@ -233,7 +233,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 
 							functionResponseJSON := []byte(`{}`)
 							functionResponseJSON, _ = sjson.SetBytes(functionResponseJSON, "id", toolCallID)
-							functionResponseJSON, _ = sjson.SetBytes(functionResponseJSON, "name", funcName)
+							functionResponseJSON, _ = sjson.SetBytes(functionResponseJSON, "name", util.SanitizeFunctionName(funcName))
 
 							responseData := ""
 							if functionResponseResult.Type == gjson.String {
@@ -398,6 +398,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 				inputSchema := util.CleanJSONSchemaForAntigravity(inputSchemaResult.Raw)
 				tool, _ := sjson.DeleteBytes([]byte(toolResult.Raw), "input_schema")
 				tool, _ = sjson.SetRawBytes(tool, "parametersJsonSchema", []byte(inputSchema))
+				tool, _ = sjson.SetBytes(tool, "name", util.SanitizeFunctionName(gjson.GetBytes(tool, "name").String()))
 				for toolKey := range gjson.ParseBytes(tool).Map() {
 					if util.InArray(allowedToolKeys, toolKey) {
 						continue
@@ -471,7 +472,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 		case "tool":
 			out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.mode", "ANY")
 			if toolChoiceName != "" {
-				out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.allowedFunctionNames", []string{toolChoiceName})
+				out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.allowedFunctionNames", []string{util.SanitizeFunctionName(toolChoiceName)})
 			}
 		}
 	}

internal/translator/antigravity/claude/antigravity_claude_response.go

@@ -44,6 +44,10 @@ type Params struct {
 
 	// Signature caching support
 	CurrentThinkingText strings.Builder // Accumulates thinking text for signature caching
+
+	// Reverse map: sanitized Gemini function name → original Claude tool name.
+	// Populated lazily on the first response chunk from the original request JSON.
+	ToolNameMap map[string]string
 }
 
 // toolUseIDCounter provides a process-wide unique counter for tool use identifiers.
@@ -71,6 +75,7 @@ func ConvertAntigravityResponseToClaude(_ context.Context, _ string, originalReq
 			HasFirstResponse: false,
 			ResponseType:     0,
 			ResponseIndex:    0,
+			ToolNameMap:      util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
 	modelName := gjson.GetBytes(requestRawJSON, "model").String()
@@ -212,7 +217,7 @@ func ConvertAntigravityResponseToClaude(_ context.Context, _ string, originalReq
 				// Handle function/tool calls from the AI model
 				// This processes tool usage requests and formats them for Claude Code API compatibility
 				params.HasToolUse = true
-				fcName := functionCallResult.Get("name").String()
+				fcName := util.RestoreSanitizedToolName(params.ToolNameMap, functionCallResult.Get("name").String())
 
 				// Handle state transitions when switching to function calls
 				// Close any existing function call block first
@@ -348,7 +353,7 @@ func resolveStopReason(params *Params) string {
 // Returns:
 //   - []byte: A Claude-compatible JSON response.
 func ConvertAntigravityResponseToClaudeNonStream(_ context.Context, _ string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) []byte {
-	_ = originalRequestRawJSON
+	toolNameMap := util.SanitizedToolNameMap(originalRequestRawJSON)
 	modelName := gjson.GetBytes(requestRawJSON, "model").String()
 
 	root := gjson.ParseBytes(rawJSON)
@@ -450,7 +455,7 @@ func ConvertAntigravityResponseToClaudeNonStream(_ context.Context, _ string, or
 				flushText()
 				hasToolCall = true
 
-				name := functionCall.Get("name").String()
+				name := util.RestoreSanitizedToolName(toolNameMap, functionCall.Get("name").String())
 				toolIDCounter++
 				toolBlock := []byte(`{"type":"tool_use","id":"","name":"","input":{}}`)
 				toolBlock, _ = sjson.SetBytes(toolBlock, "id", fmt.Sprintf("tool_%d", toolIDCounter))

internal/translator/antigravity/openai/chat-completions/antigravity_openai_request.go

@@ -286,7 +286,7 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 							continue
 						}
 						fid := tc.Get("id").String()
-						fname := tc.Get("function.name").String()
+						fname := util.SanitizeFunctionName(tc.Get("function.name").String())
 						fargs := tc.Get("function.arguments").String()
 						node, _ = sjson.SetBytes(node, "parts."+itoa(p)+".functionCall.id", fid)
 						node, _ = sjson.SetBytes(node, "parts."+itoa(p)+".functionCall.name", fname)
@@ -309,7 +309,7 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 					for _, fid := range fIDs {
 						if name, ok := tcID2Name[fid]; ok {
 							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.id", fid)
-							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", name)
+							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", util.SanitizeFunctionName(name))
 							resp := toolResponses[fid]
 							if resp == "" {
 								resp = "{}"
@@ -384,7 +384,9 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 						}
 						fnRaw = string(fnRawBytes)
 					}
-					fnRaw, _ = sjson.Delete(fnRaw, "strict")
+					fnRawBytes := []byte(fnRaw)
+					fnRawBytes, _ = sjson.SetBytes(fnRawBytes, "name", util.SanitizeFunctionName(fn.Get("name").String()))
+					fnRaw, _ = sjson.Delete(string(fnRawBytes), "strict")
 					if !hasFunction {
 						functionToolNode, _ = sjson.SetRawBytes(functionToolNode, "functionDeclarations", []byte("[]"))
 					}

internal/translator/antigravity/openai/chat-completions/antigravity_openai_response.go

@@ -13,6 +13,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	log "github.com/sirupsen/logrus"
 
 	. "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/gemini/openai/chat-completions"
@@ -26,6 +27,7 @@ type convertCliResponseToOpenAIChatParams struct {
 	FunctionIndex        int
 	SawToolCall          bool   // Tracks if any tool call was seen in the entire stream
 	UpstreamFinishReason string // Caches the upstream finish reason for final chunk
+	SanitizedNameMap     map[string]string
 }
 
 // functionCallIDCounter provides a process-wide unique counter for function call identifiers.
@@ -50,8 +52,12 @@ func ConvertAntigravityResponseToOpenAI(_ context.Context, _ string, originalReq
 		*param = &convertCliResponseToOpenAIChatParams{
 			UnixTimestamp:    0,
 			FunctionIndex:    0,
+			SanitizedNameMap: util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
+	if (*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap == nil {
+		(*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap = util.SanitizedToolNameMap(originalRequestRawJSON)
+	}
 
 	if bytes.Equal(rawJSON, []byte("[DONE]")) {
 		return [][]byte{}
@@ -159,7 +165,7 @@ func ConvertAntigravityResponseToOpenAI(_ context.Context, _ string, originalReq
 				}
 
 				functionCallTemplate := []byte(`{"id": "","index": 0,"type": "function","function": {"name": "","arguments": ""}}`)
-				fcName := functionCallResult.Get("name").String()
+				fcName := util.RestoreSanitizedToolName((*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap, functionCallResult.Get("name").String())
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "id", fmt.Sprintf("%s-%d-%d", fcName, time.Now().UnixNano(), atomic.AddUint64(&functionCallIDCounter, 1)))
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "index", functionCallIndex)
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "function.name", fcName)

internal/translator/gemini-cli/claude/gemini-cli_claude_request.go

@@ -89,7 +89,7 @@ func ConvertClaudeRequestToCLI(modelName string, inputRawJSON []byte, _ bool) []
 						contentJSON, _ = sjson.SetRawBytes(contentJSON, "parts.-1", part)
 
 					case "tool_use":
-						functionName := contentResult.Get("name").String()
+						functionName := util.SanitizeFunctionName(contentResult.Get("name").String())
 						functionArgs := contentResult.Get("input").String()
 						argsResult := gjson.Parse(functionArgs)
 						if argsResult.IsObject() && gjson.Valid(functionArgs) {
@@ -112,7 +112,7 @@ func ConvertClaudeRequestToCLI(modelName string, inputRawJSON []byte, _ bool) []
 						}
 						responseData := contentResult.Get("content").Raw
 						part := []byte(`{"functionResponse":{"name":"","response":{"result":""}}}`)
-						part, _ = sjson.SetBytes(part, "functionResponse.name", funcName)
+						part, _ = sjson.SetBytes(part, "functionResponse.name", util.SanitizeFunctionName(funcName))
 						part, _ = sjson.SetBytes(part, "functionResponse.response.result", responseData)
 						contentJSON, _ = sjson.SetRawBytes(contentJSON, "parts.-1", part)
 
@@ -151,6 +151,7 @@ func ConvertClaudeRequestToCLI(modelName string, inputRawJSON []byte, _ bool) []
 				inputSchema := util.CleanJSONSchemaForGemini(inputSchemaResult.Raw)
 				tool, _ := sjson.DeleteBytes([]byte(toolResult.Raw), "input_schema")
 				tool, _ = sjson.SetRawBytes(tool, "parametersJsonSchema", []byte(inputSchema))
+				tool, _ = sjson.SetBytes(tool, "name", util.SanitizeFunctionName(gjson.GetBytes(tool, "name").String()))
 				tool, _ = sjson.DeleteBytes(tool, "strict")
 				tool, _ = sjson.DeleteBytes(tool, "input_examples")
 				tool, _ = sjson.DeleteBytes(tool, "type")
@@ -194,7 +195,7 @@ func ConvertClaudeRequestToCLI(modelName string, inputRawJSON []byte, _ bool) []
 		case "tool":
 			out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.mode", "ANY")
 			if toolChoiceName != "" {
-				out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.allowedFunctionNames", []string{toolChoiceName})
+				out, _ = sjson.SetBytes(out, "request.toolConfig.functionCallingConfig.allowedFunctionNames", []string{util.SanitizeFunctionName(toolChoiceName)})
 			}
 		}
 	}

internal/translator/gemini-cli/claude/gemini-cli_claude_response.go

@@ -28,6 +28,9 @@ type Params struct {
 	ResponseType     int  // Current response type: 0=none, 1=content, 2=thinking, 3=function
 	ResponseIndex    int  // Index counter for content blocks in the streaming response
 	HasContent       bool // Tracks whether any content (text, thinking, or tool use) has been output
+
+	// Reverse map: sanitized Gemini function name → original Claude tool name.
+	ToolNameMap map[string]string
 }
 
 // toolUseIDCounter provides a process-wide unique counter for tool use identifiers.
@@ -55,6 +58,7 @@ func ConvertGeminiCLIResponseToClaude(_ context.Context, _ string, originalReque
 			HasFirstResponse: false,
 			ResponseType:     0,
 			ResponseIndex:    0,
+			ToolNameMap:      util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
 
@@ -165,7 +169,7 @@ func ConvertGeminiCLIResponseToClaude(_ context.Context, _ string, originalReque
 				// Handle function/tool calls from the AI model
 				// This processes tool usage requests and formats them for Claude Code API compatibility
 				usedTool = true
-				fcName := functionCallResult.Get("name").String()
+				fcName := util.RestoreSanitizedToolName((*param).(*Params).ToolNameMap, functionCallResult.Get("name").String())
 
 				// Handle state transitions when switching to function calls
 				// Close any existing function call block first
@@ -248,7 +252,7 @@ func ConvertGeminiCLIResponseToClaude(_ context.Context, _ string, originalReque
 // Returns:
 //   - []byte: A Claude-compatible JSON response.
 func ConvertGeminiCLIResponseToClaudeNonStream(_ context.Context, _ string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) []byte {
-	_ = originalRequestRawJSON
+	toolNameMap := util.SanitizedToolNameMap(originalRequestRawJSON)
 	_ = requestRawJSON
 
 	root := gjson.ParseBytes(rawJSON)
@@ -306,7 +310,7 @@ func ConvertGeminiCLIResponseToClaudeNonStream(_ context.Context, _ string, orig
 				flushText()
 				hasToolCall = true
 
-				name := functionCall.Get("name").String()
+				name := util.RestoreSanitizedToolName(toolNameMap, functionCall.Get("name").String())
 				toolIDCounter++
 				toolBlock := []byte(`{"type":"tool_use","id":"","name":"","input":{}}`)
 				toolBlock, _ = sjson.SetBytes(toolBlock, "id", fmt.Sprintf("tool_%d", toolIDCounter))

internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_request.go

@@ -251,7 +251,7 @@ func ConvertOpenAIRequestToGeminiCLI(modelName string, inputRawJSON []byte, _ bo
 							continue
 						}
 						fid := tc.Get("id").String()
-						fname := tc.Get("function.name").String()
+						fname := util.SanitizeFunctionName(tc.Get("function.name").String())
 						fargs := tc.Get("function.arguments").String()
 						node, _ = sjson.SetBytes(node, "parts."+itoa(p)+".functionCall.name", fname)
 						node, _ = sjson.SetRawBytes(node, "parts."+itoa(p)+".functionCall.args", []byte(fargs))
@@ -268,7 +268,7 @@ func ConvertOpenAIRequestToGeminiCLI(modelName string, inputRawJSON []byte, _ bo
 					pp := 0
 					for _, fid := range fIDs {
 						if name, ok := tcID2Name[fid]; ok {
-							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", name)
+							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", util.SanitizeFunctionName(name))
 							resp := toolResponses[fid]
 							if resp == "" {
 								resp = "{}"
@@ -331,6 +331,7 @@ func ConvertOpenAIRequestToGeminiCLI(modelName string, inputRawJSON []byte, _ bo
 							continue
 						}
 					}
+					fnRaw, _ = sjson.SetBytes(fnRaw, "name", util.SanitizeFunctionName(fn.Get("name").String()))
 					fnRaw, _ = sjson.DeleteBytes(fnRaw, "strict")
 					if !hasFunction {
 						functionToolNode, _ = sjson.SetRawBytes(functionToolNode, "functionDeclarations", []byte("[]"))

internal/translator/gemini-cli/openai/chat-completions/gemini-cli_openai_response.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	. "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/gemini/openai/chat-completions"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -23,6 +24,7 @@ import (
 type convertCliResponseToOpenAIChatParams struct {
 	UnixTimestamp    int64
 	FunctionIndex    int
+	SanitizedNameMap map[string]string
 }
 
 // functionCallIDCounter provides a process-wide unique counter for function call identifiers.
@@ -47,8 +49,12 @@ func ConvertCliResponseToOpenAI(_ context.Context, _ string, originalRequestRawJ
 		*param = &convertCliResponseToOpenAIChatParams{
 			UnixTimestamp:    0,
 			FunctionIndex:    0,
+			SanitizedNameMap: util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
+	if (*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap == nil {
+		(*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap = util.SanitizedToolNameMap(originalRequestRawJSON)
+	}
 
 	if bytes.Equal(rawJSON, []byte("[DONE]")) {
 		return [][]byte{}
@@ -163,7 +169,7 @@ func ConvertCliResponseToOpenAI(_ context.Context, _ string, originalRequestRawJ
 				}
 
 				functionCallTemplate := []byte(`{"id":"","index":0,"type":"function","function":{"name":"","arguments":""}}`)
-				fcName := functionCallResult.Get("name").String()
+				fcName := util.RestoreSanitizedToolName((*param).(*convertCliResponseToOpenAIChatParams).SanitizedNameMap, functionCallResult.Get("name").String())
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "id", fmt.Sprintf("%s-%d-%d", fcName, time.Now().UnixNano(), atomic.AddUint64(&functionCallIDCounter, 1)))
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "index", functionCallIndex)
 				functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "function.name", fcName)

internal/translator/gemini/claude/gemini_claude_request.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/translator/gemini/common"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -90,6 +91,7 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 								functionName = derived
 							}
 						}
+						functionName = util.SanitizeFunctionName(functionName)
 						functionArgs := contentResult.Get("input").String()
 						argsResult := gjson.Parse(functionArgs)
 						if argsResult.IsObject() && gjson.Valid(functionArgs) {
@@ -109,6 +111,7 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 						if funcName == "" {
 							funcName = toolCallID
 						}
+						funcName = util.SanitizeFunctionName(funcName)
 						responseData := contentResult.Get("content").Raw
 						part := []byte(`{"functionResponse":{"name":"","response":{"result":""}}}`)
 						part, _ = sjson.SetBytes(part, "functionResponse.name", funcName)
@@ -165,6 +168,7 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 				tool, _ = sjson.DeleteBytes(tool, "type")
 				tool, _ = sjson.DeleteBytes(tool, "cache_control")
 				tool, _ = sjson.DeleteBytes(tool, "defer_loading")
+				tool, _ = sjson.SetBytes(tool, "name", util.SanitizeFunctionName(gjson.GetBytes(tool, "name").String()))
 				if gjson.ValidBytes(tool) && gjson.ParseBytes(tool).IsObject() {
 					if !hasTools {
 						out, _ = sjson.SetRawBytes(out, "tools", []byte(`[{"functionDeclarations":[]}]`))
@@ -202,7 +206,7 @@ func ConvertClaudeRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 		case "tool":
 			out, _ = sjson.SetBytes(out, "toolConfig.functionCallingConfig.mode", "ANY")
 			if toolChoiceName != "" {
-				out, _ = sjson.SetBytes(out, "toolConfig.functionCallingConfig.allowedFunctionNames", []string{toolChoiceName})
+				out, _ = sjson.SetBytes(out, "toolConfig.functionCallingConfig.allowedFunctionNames", []string{util.SanitizeFunctionName(toolChoiceName)})
 			}
 		}
 	}

internal/translator/gemini/claude/gemini_claude_response.go

@@ -27,6 +27,7 @@ type Params struct {
 	ResponseIndex    int
 	HasContent       bool // Tracks whether any content (text, thinking, or tool use) has been output
 	ToolNameMap      map[string]string
+	SanitizedNameMap map[string]string
 	SawToolCall      bool
 }
 
@@ -57,6 +58,7 @@ func ConvertGeminiResponseToClaude(_ context.Context, _ string, originalRequestR
 			ResponseType:     0,
 			ResponseIndex:    0,
 			ToolNameMap:      util.ToolNameMapFromClaudeRequest(originalRequestRawJSON),
+			SanitizedNameMap: util.SanitizedToolNameMap(originalRequestRawJSON),
 			SawToolCall:      false,
 		}
 	}
@@ -167,6 +169,7 @@ func ConvertGeminiResponseToClaude(_ context.Context, _ string, originalRequestR
 				// This processes tool usage requests and formats them for Claude API compatibility
 				(*param).(*Params).SawToolCall = true
 				upstreamToolName := functionCallResult.Get("name").String()
+				upstreamToolName = util.RestoreSanitizedToolName((*param).(*Params).SanitizedNameMap, upstreamToolName)
 				clientToolName := util.MapToolName((*param).(*Params).ToolNameMap, upstreamToolName)
 
 				// FIX: Handle streaming split/delta where name might be empty in subsequent chunks.
@@ -260,6 +263,7 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 
 	root := gjson.ParseBytes(rawJSON)
 	toolNameMap := util.ToolNameMapFromClaudeRequest(originalRequestRawJSON)
+	sanitizedNameMap := util.SanitizedToolNameMap(originalRequestRawJSON)
 
 	out := []byte(`{"id":"","type":"message","role":"assistant","model":"","content":[],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":0,"output_tokens":0}}`)
 	out, _ = sjson.SetBytes(out, "id", root.Get("responseId").String())
@@ -315,6 +319,7 @@ func ConvertGeminiResponseToClaudeNonStream(_ context.Context, _ string, origina
 				hasToolCall = true
 
 				upstreamToolName := functionCall.Get("name").String()
+				upstreamToolName = util.RestoreSanitizedToolName(sanitizedNameMap, upstreamToolName)
 				clientToolName := util.MapToolName(toolNameMap, upstreamToolName)
 				toolIDCounter++
 				toolBlock := []byte(`{"type":"tool_use","id":"","name":"","input":{}}`)

internal/translator/gemini/openai/chat-completions/gemini_openai_request.go

@@ -257,7 +257,7 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 							continue
 						}
 						fid := tc.Get("id").String()
-						fname := tc.Get("function.name").String()
+						fname := util.SanitizeFunctionName(tc.Get("function.name").String())
 						fargs := tc.Get("function.arguments").String()
 						node, _ = sjson.SetBytes(node, "parts."+itoa(p)+".functionCall.name", fname)
 						node, _ = sjson.SetRawBytes(node, "parts."+itoa(p)+".functionCall.args", []byte(fargs))
@@ -274,7 +274,7 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 					pp := 0
 					for _, fid := range fIDs {
 						if name, ok := tcID2Name[fid]; ok {
-							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", name)
+							toolNode, _ = sjson.SetBytes(toolNode, "parts."+itoa(pp)+".functionResponse.name", util.SanitizeFunctionName(name))
 							resp := toolResponses[fid]
 							if resp == "" {
 								resp = "{}"
@@ -341,6 +341,9 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 						}
 						fnRaw = string(fnRawBytes)
 					}
+					fnRawBytes := []byte(fnRaw)
+					fnRawBytes, _ = sjson.SetBytes(fnRawBytes, "name", util.SanitizeFunctionName(fn.Get("name").String()))
+					fnRaw = string(fnRawBytes)
 					fnRaw, _ = sjson.Delete(fnRaw, "strict")
 					if !hasFunction {
 						functionToolNode, _ = sjson.SetRawBytes(functionToolNode, "functionDeclarations", []byte("[]"))

internal/translator/gemini/openai/chat-completions/gemini_openai_response.go

@@ -13,6 +13,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -23,6 +24,7 @@ type convertGeminiResponseToOpenAIChatParams struct {
 	UnixTimestamp int64
 	// FunctionIndex tracks tool call indices per candidate index to support multiple candidates.
 	FunctionIndex    map[int]int
+	SanitizedNameMap map[string]string
 }
 
 // functionCallIDCounter provides a process-wide unique counter for function call identifiers.
@@ -48,6 +50,7 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 		*param = &convertGeminiResponseToOpenAIChatParams{
 			UnixTimestamp:    0,
 			FunctionIndex:    make(map[int]int),
+			SanitizedNameMap: util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
 
@@ -56,6 +59,9 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 	if p.FunctionIndex == nil {
 		p.FunctionIndex = make(map[int]int)
 	}
+	if p.SanitizedNameMap == nil {
+		p.SanitizedNameMap = util.SanitizedToolNameMap(originalRequestRawJSON)
+	}
 
 	if bytes.HasPrefix(rawJSON, []byte("data:")) {
 		rawJSON = bytes.TrimSpace(rawJSON[5:])
@@ -191,7 +197,7 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 						}
 
 						functionCallTemplate := []byte(`{"id":"","index":0,"type":"function","function":{"name":"","arguments":""}}`)
-						fcName := functionCallResult.Get("name").String()
+						fcName := util.RestoreSanitizedToolName(p.SanitizedNameMap, functionCallResult.Get("name").String())
 						functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "id", fmt.Sprintf("%s-%d-%d", fcName, time.Now().UnixNano(), atomic.AddUint64(&functionCallIDCounter, 1)))
 						functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "index", functionCallIndex)
 						functionCallTemplate, _ = sjson.SetBytes(functionCallTemplate, "function.name", fcName)
@@ -265,6 +271,7 @@ func ConvertGeminiResponseToOpenAI(_ context.Context, _ string, originalRequestR
 // Returns:
 //   - []byte: An OpenAI-compatible JSON response containing all message content and metadata
 func ConvertGeminiResponseToOpenAINonStream(_ context.Context, _ string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) []byte {
+	sanitizedNameMap := util.SanitizedToolNameMap(originalRequestRawJSON)
 	var unixTimestamp int64
 	// Initialize template with an empty choices array to support multiple candidates.
 	template := []byte(`{"id":"","object":"chat.completion","created":123456,"model":"model","choices":[]}`)
@@ -358,7 +365,7 @@ func ConvertGeminiResponseToOpenAINonStream(_ context.Context, _ string, origina
 							choiceTemplate, _ = sjson.SetRawBytes(choiceTemplate, "message.tool_calls", []byte(`[]`))
 						}
 						functionCallItemTemplate := []byte(`{"id":"","type":"function","function":{"name":"","arguments":""}}`)
-						fcName := functionCallResult.Get("name").String()
+						fcName := util.RestoreSanitizedToolName(sanitizedNameMap, functionCallResult.Get("name").String())
 						functionCallItemTemplate, _ = sjson.SetBytes(functionCallItemTemplate, "id", fmt.Sprintf("%s-%d-%d", fcName, time.Now().UnixNano(), atomic.AddUint64(&functionCallIDCounter, 1)))
 						functionCallItemTemplate, _ = sjson.SetBytes(functionCallItemTemplate, "function.name", fcName)
 						if fcArgsResult := functionCallResult.Get("args"); fcArgsResult.Exists() {

internal/translator/gemini/openai/responses/gemini_openai-responses_request.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/translator/gemini/common"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -291,7 +292,7 @@ func ConvertOpenAIResponsesRequestToGemini(modelName string, inputRawJSON []byte
 
 			case "function_call":
 				// Handle function calls - convert to model message with functionCall
-				name := item.Get("name").String()
+				name := util.SanitizeFunctionName(item.Get("name").String())
 				arguments := item.Get("arguments").String()
 
 				modelContent := []byte(`{"role":"model","parts":[]}`)
@@ -333,6 +334,7 @@ func ConvertOpenAIResponsesRequestToGemini(modelName string, inputRawJSON []byte
 						return true
 					})
 				}
+				functionName = util.SanitizeFunctionName(functionName)
 
 				functionResponse, _ = sjson.SetBytes(functionResponse, "functionResponse.name", functionName)
 				functionResponse, _ = sjson.SetBytes(functionResponse, "functionResponse.id", callID)
@@ -375,7 +377,7 @@ func ConvertOpenAIResponsesRequestToGemini(modelName string, inputRawJSON []byte
 				funcDecl := []byte(`{"name":"","description":"","parametersJsonSchema":{}}`)
 
 				if name := tool.Get("name"); name.Exists() {
-					funcDecl, _ = sjson.SetBytes(funcDecl, "name", name.String())
+					funcDecl, _ = sjson.SetBytes(funcDecl, "name", util.SanitizeFunctionName(name.String()))
 				}
 				if desc := tool.Get("description"); desc.Exists() {
 					funcDecl, _ = sjson.SetBytes(funcDecl, "description", desc.String())

internal/translator/gemini/openai/responses/gemini_openai-responses_response.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	translatorcommon "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/common"
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -41,6 +42,7 @@ type geminiToResponsesState struct {
 	FuncNames        map[int]string
 	FuncCallIDs      map[int]string
 	FuncDone         map[int]bool
+	SanitizedNameMap map[string]string
 }
 
 // responseIDCounter provides a process-wide unique counter for synthesized response identifiers.
@@ -94,6 +96,7 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 			FuncNames:        make(map[int]string),
 			FuncCallIDs:      make(map[int]string),
 			FuncDone:         make(map[int]bool),
+			SanitizedNameMap: util.SanitizedToolNameMap(originalRequestRawJSON),
 		}
 	}
 	st := (*param).(*geminiToResponsesState)
@@ -109,6 +112,9 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 	if st.FuncDone == nil {
 		st.FuncDone = make(map[int]bool)
 	}
+	if st.SanitizedNameMap == nil {
+		st.SanitizedNameMap = util.SanitizedToolNameMap(originalRequestRawJSON)
+	}
 
 	if bytes.HasPrefix(rawJSON, []byte("data:")) {
 		rawJSON = bytes.TrimSpace(rawJSON[5:])
@@ -306,7 +312,7 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 				// Responses streaming requires message done events before the next output_item.added.
 				finalizeReasoning()
 				finalizeMessage()
-				name := fc.Get("name").String()
+				name := util.RestoreSanitizedToolName(st.SanitizedNameMap, fc.Get("name").String())
 				idx := st.NextIndex
 				st.NextIndex++
 				// Ensure buffers
@@ -565,6 +571,7 @@ func ConvertGeminiResponseToOpenAIResponses(_ context.Context, modelName string,
 func ConvertGeminiResponseToOpenAIResponsesNonStream(_ context.Context, _ string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) []byte {
 	root := gjson.ParseBytes(rawJSON)
 	root = unwrapGeminiResponseRoot(root)
+	sanitizedNameMap := util.SanitizedToolNameMap(originalRequestRawJSON)
 
 	// Base response scaffold
 	resp := []byte(`{"id":"","object":"response","created_at":0,"status":"completed","background":false,"error":null,"incomplete_details":null}`)
@@ -694,7 +701,7 @@ func ConvertGeminiResponseToOpenAIResponsesNonStream(_ context.Context, _ string
 				return true
 			}
 			if fc := p.Get("functionCall"); fc.Exists() {
-				name := fc.Get("name").String()
+				name := util.RestoreSanitizedToolName(sanitizedNameMap, fc.Get("name").String())
 				args := fc.Get("args")
 				callID := fmt.Sprintf("call_%x_%d", time.Now().UnixNano(), atomic.AddUint64(&funcCallIDCounter, 1))
 				itemJSON := []byte(`{"id":"","type":"function_call","status":"completed","arguments":"","call_id":"","name":""}`)

internal/util/sanitize_test.go

@@ -54,3 +54,77 @@ func TestSanitizeFunctionName(t *testing.T) {
 		})
 	}
 }
+
+func TestSanitizedToolNameMap(t *testing.T) {
+	t.Run("returns map for tools needing sanitization", func(t *testing.T) {
+		raw := []byte(`{"tools":[
+			{"name":"valid_tool","input_schema":{}},
+			{"name":"mcp/server/read","input_schema":{}},
+			{"name":"tool@v2","input_schema":{}}
+		]}`)
+		m := SanitizedToolNameMap(raw)
+		if m == nil {
+			t.Fatal("expected non-nil map")
+		}
+		if m["mcp_server_read"] != "mcp/server/read" {
+			t.Errorf("expected mcp_server_read → mcp/server/read, got %q", m["mcp_server_read"])
+		}
+		if m["tool_v2"] != "tool@v2" {
+			t.Errorf("expected tool_v2 → tool@v2, got %q", m["tool_v2"])
+		}
+		if _, exists := m["valid_tool"]; exists {
+			t.Error("valid_tool should not be in the map (no sanitization needed)")
+		}
+	})
+
+	t.Run("returns nil when no tools need sanitization", func(t *testing.T) {
+		raw := []byte(`{"tools":[{"name":"Read","input_schema":{}},{"name":"Write","input_schema":{}}]}`)
+		m := SanitizedToolNameMap(raw)
+		if m != nil {
+			t.Errorf("expected nil, got %v", m)
+		}
+	})
+
+	t.Run("returns nil for empty/missing tools", func(t *testing.T) {
+		if m := SanitizedToolNameMap([]byte(`{}`)); m != nil {
+			t.Error("expected nil for no tools")
+		}
+		if m := SanitizedToolNameMap(nil); m != nil {
+			t.Error("expected nil for nil input")
+		}
+	})
+
+	t.Run("collision keeps first mapping", func(t *testing.T) {
+		raw := []byte(`{"tools":[
+			{"name":"read/file","input_schema":{}},
+			{"name":"read@file","input_schema":{}}
+		]}`)
+		m := SanitizedToolNameMap(raw)
+		if m == nil {
+			t.Fatal("expected non-nil map")
+		}
+		if m["read_file"] != "read/file" {
+			t.Errorf("expected first mapping read/file, got %q", m["read_file"])
+		}
+	})
+}
+
+func TestRestoreSanitizedToolName(t *testing.T) {
+	m := map[string]string{
+		"mcp_server_read": "mcp/server/read",
+		"tool_v2":         "tool@v2",
+	}
+
+	if got := RestoreSanitizedToolName(m, "mcp_server_read"); got != "mcp/server/read" {
+		t.Errorf("expected mcp/server/read, got %q", got)
+	}
+	if got := RestoreSanitizedToolName(m, "unknown"); got != "unknown" {
+		t.Errorf("expected passthrough for unknown, got %q", got)
+	}
+	if got := RestoreSanitizedToolName(nil, "name"); got != "name" {
+		t.Errorf("expected passthrough for nil map, got %q", got)
+	}
+	if got := RestoreSanitizedToolName(m, ""); got != "" {
+		t.Errorf("expected empty for empty name, got %q", got)
+	}
+}

internal/util/translator.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"strings"
 
+	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
@@ -243,6 +244,9 @@ func ToolNameMapFromClaudeRequest(rawJSON []byte) map[string]string {
 	out := make(map[string]string, len(toolResults))
 	tools.ForEach(func(_, tool gjson.Result) bool {
 		name := strings.TrimSpace(tool.Get("name").String())
+		if name == "" {
+			name = strings.TrimSpace(tool.Get("function.name").String())
+		}
 		if name == "" {
 			return true
 		}
@@ -271,3 +275,54 @@ func MapToolName(toolNameMap map[string]string, name string) string {
 	}
 	return name
 }
+
+// SanitizedToolNameMap builds a sanitized-name → original-name map from Claude request tools.
+// It is used to restore exact tool names for clients (e.g. Claude Code) after the proxy
+// sanitizes tool names for Gemini/Vertex API compatibility via SanitizeFunctionName.
+// Only entries where sanitization actually changes the name are included.
+func SanitizedToolNameMap(rawJSON []byte) map[string]string {
+	if len(rawJSON) == 0 || !gjson.ValidBytes(rawJSON) {
+		return nil
+	}
+
+	tools := gjson.GetBytes(rawJSON, "tools")
+	if !tools.Exists() || !tools.IsArray() {
+		return nil
+	}
+
+	out := make(map[string]string)
+	tools.ForEach(func(_, tool gjson.Result) bool {
+		name := strings.TrimSpace(tool.Get("name").String())
+		if name == "" {
+			return true
+		}
+		sanitized := SanitizeFunctionName(name)
+		if sanitized == name {
+			return true
+		}
+		if _, exists := out[sanitized]; !exists {
+			out[sanitized] = name
+		} else {
+			log.Warnf("sanitized tool name collision: %q and %q both map to %q, keeping first", out[sanitized], name, sanitized)
+		}
+		return true
+	})
+
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
+// RestoreSanitizedToolName looks up a sanitized function name in the provided map
+// and returns the original client-facing name. If no mapping exists, it returns
+// the sanitized name unchanged.
+func RestoreSanitizedToolName(toolNameMap map[string]string, sanitizedName string) string {
+	if sanitizedName == "" || toolNameMap == nil {
+		return sanitizedName
+	}
+	if original, ok := toolNameMap[sanitizedName]; ok {
+		return original
+	}
+	return sanitizedName
+}