feat(antigravity): add function ID to FunctionCall and FunctionResponse models

internal/interfaces/client_models.go

@@ -85,6 +85,9 @@ type InlineData struct {
 // FunctionCall represents a tool call requested by the model.
 // It includes the function name and its arguments that the model wants to execute.
 type FunctionCall struct {
+	// ID is the identifier of the function to be called.
+	ID string `json:"id,omitempty"`
+
 	// Name is the identifier of the function to be called.
 	Name string `json:"name"`
 
@@ -95,6 +98,9 @@ type FunctionCall struct {
 // FunctionResponse represents the result of a tool execution.
 // This is sent back to the model after a tool call has been processed.
 type FunctionResponse struct {
+	// ID is the identifier of the function to be called.
+	ID string `json:"id,omitempty"`
+
 	// Name is the identifier of the function that was called.
 	Name string `json:"name"`
 

internal/translator/antigravity/claude/antigravity_claude_request.go

@@ -89,10 +89,11 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 					} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "tool_use" {
 						functionName := contentResult.Get("name").String()
 						functionArgs := contentResult.Get("input").String()
+						functionID := contentResult.Get("id").String()
 						var args map[string]any
 						if err := json.Unmarshal([]byte(functionArgs), &args); err == nil {
 							clientContent.Parts = append(clientContent.Parts, client.Part{
-								FunctionCall:     &client.FunctionCall{Name: functionName, Args: args},
+								FunctionCall:     &client.FunctionCall{ID: functionID, Name: functionName, Args: args},
 								ThoughtSignature: geminiCLIClaudeThoughtSignature,
 							})
 						}
@@ -105,7 +106,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 								funcName = strings.Join(toolCallIDs[0:len(toolCallIDs)-1], "-")
 							}
 							responseData := contentResult.Get("content").Raw
-							functionResponse := client.FunctionResponse{Name: funcName, Response: map[string]interface{}{"result": responseData}}
+							functionResponse := client.FunctionResponse{ID: toolCallID, Name: funcName, Response: map[string]interface{}{"result": responseData}}
 							clientContent.Parts = append(clientContent.Parts, client.Part{FunctionResponse: &functionResponse})
 						}
 					}

internal/translator/antigravity/claude/antigravity_claude_response.go

@@ -141,6 +141,8 @@ func ConvertAntigravityResponseToClaude(_ context.Context, _ string, originalReq
 						params.ResponseType = 2 // Set state to thinking
 					}
 				} else {
+					finishReasonResult := gjson.GetBytes(rawJSON, "response.candidates.0.finishReason")
+					if partTextResult.String() != "" || !finishReasonResult.Exists() {
 						// Process regular text content (user-visible output)
 						// Continue existing text block if already in content state
 						if params.ResponseType == 1 {
@@ -172,6 +174,7 @@ func ConvertAntigravityResponseToClaude(_ context.Context, _ string, originalReq
 							params.ResponseType = 1 // Set state to content
 						}
 					}
+				}
 			} else if functionCallResult.Exists() {
 				// Handle function/tool calls from the AI model
 				// This processes tool usage requests and formats them for Claude Code API compatibility

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

@@ -251,6 +251,7 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 							fid := tc.Get("id").String()
 							fname := 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)
 							node, _ = sjson.SetRawBytes(node, "parts."+itoa(p)+".functionCall.args", []byte(fargs))
 							node, _ = sjson.SetBytes(node, "parts."+itoa(p)+".thoughtSignature", geminiCLIFunctionThoughtSignature)
@@ -266,6 +267,7 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 						pp := 0
 						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)
 								resp := toolResponses[fid]
 								if resp == "" {

internal/translator/codex/gemini/codex_gemini_response.go

@@ -327,7 +327,7 @@ func buildReverseMapFromGeminiOriginal(original []byte) map[string]string {
 func mustMarshalJSON(v interface{}) string {
 	data, err := json.Marshal(v)
 	if err != nil {
-		panic(err)
+		return ""
 	}
 	return string(data)
 }

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

@@ -249,6 +249,7 @@ func ConvertOpenAIResponsesRequestToGemini(modelName string, inputRawJSON []byte
 				functionCall := `{"functionCall":{"name":"","args":{}}}`
 				functionCall, _ = sjson.Set(functionCall, "functionCall.name", name)
 				functionCall, _ = sjson.Set(functionCall, "thoughtSignature", geminiResponsesThoughtSignature)
+				functionCall, _ = sjson.Set(functionCall, "functionCall.id", item.Get("call_id").String())
 
 				// Parse arguments JSON string and set as args object
 				if arguments != "" {
@@ -285,6 +286,7 @@ func ConvertOpenAIResponsesRequestToGemini(modelName string, inputRawJSON []byte
 				}
 
 				functionResponse, _ = sjson.Set(functionResponse, "functionResponse.name", functionName)
+				functionResponse, _ = sjson.Set(functionResponse, "functionResponse.id", callID)
 
 				// Set the raw JSON output directly (preserves string encoding)
 				if outputRaw != "" && outputRaw != "null" {