refactor(translator): enhance signature handling in Claude and Gemini requests, streamline cache usage and remove unnecessary tests

go.mod

@@ -21,6 +21,7 @@ require (
 	golang.org/x/crypto v0.45.0
 	golang.org/x/net v0.47.0
 	golang.org/x/oauth2 v0.30.0
+	golang.org/x/text v0.31.0
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1
 	gopkg.in/yaml.v3 v3.0.1
 )
@@ -70,7 +71,6 @@ require (
 	golang.org/x/arch v0.8.0 // indirect
 	golang.org/x/sync v0.18.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect
-	golang.org/x/text v0.31.0 // indirect
 	google.golang.org/protobuf v1.34.1 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 )

internal/translator/antigravity/claude/antigravity_claude_request.go

@@ -98,15 +98,9 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 						// Use GetThinkingText to handle wrapped thinking objects
 						thinkingText := thinking.GetThinkingText(contentResult)
 
-						signature := ""
-						signatureResult := contentResult.Get("signature")
-						hasClientSignature := signatureResult.Exists() && signatureResult.String() != ""
-
-						// Only consider cached signatures when the client provided a signature.
-						// Unsigned thinking blocks must be dropped.
-						if hasClientSignature {
 						// Always try cached signature first (more reliable than client-provided)
-							// Client may send stale or invalid signatures from other requests
+						// Client may send stale or invalid signatures from different sessions
+						signature := ""
 						if thinkingText != "" {
 							if cachedSig := cache.GetCachedSignature(modelName, thinkingText); cachedSig != "" {
 								signature = cachedSig
@@ -116,6 +110,7 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 
 						// Fallback to client signature only if cache miss and client signature is valid
 						if signature == "" {
+							signatureResult := contentResult.Get("signature")
 							clientSignature := ""
 							if signatureResult.Exists() && signatureResult.String() != "" {
 								arrayClientSignatures := strings.SplitN(signatureResult.String(), "#", 2)
@@ -130,7 +125,6 @@ func ConvertClaudeRequestToAntigravity(modelName string, inputRawJSON []byte, _
 							}
 							// log.Debugf("Using client-provided signature for thinking block")
 						}
-						}
 
 						// Store for subsequent tool_use in the same message
 						if cache.HasValidSignature(modelName, signature) {

internal/translator/antigravity/claude/antigravity_claude_request_test.go

@@ -74,6 +74,8 @@ func TestConvertClaudeRequestToAntigravity_RoleMapping(t *testing.T) {
 }
 
 func TestConvertClaudeRequestToAntigravity_ThinkingBlocks(t *testing.T) {
+	cache.ClearSignatureCache("")
+
 	// Valid signature must be at least 50 characters
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
 	thinkingText := "Let me think..."
@@ -115,6 +117,8 @@ func TestConvertClaudeRequestToAntigravity_ThinkingBlocks(t *testing.T) {
 }
 
 func TestConvertClaudeRequestToAntigravity_ThinkingBlockWithoutSignature(t *testing.T) {
+	cache.ClearSignatureCache("")
+
 	// Unsigned thinking blocks should be removed entirely (not converted to text)
 	inputJSON := []byte(`{
 		"model": "claude-sonnet-4-5-thinking",
@@ -236,6 +240,8 @@ func TestConvertClaudeRequestToAntigravity_ToolUse(t *testing.T) {
 }
 
 func TestConvertClaudeRequestToAntigravity_ToolUse_WithSignature(t *testing.T) {
+	cache.ClearSignatureCache("")
+
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
 	thinkingText := "Let me think..."
 
@@ -277,6 +283,8 @@ func TestConvertClaudeRequestToAntigravity_ToolUse_WithSignature(t *testing.T) {
 }
 
 func TestConvertClaudeRequestToAntigravity_ReorderThinking(t *testing.T) {
+	cache.ClearSignatureCache("")
+
 	// Case: text block followed by thinking block -> should be reordered to thinking first
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
 	thinkingText := "Planning..."
@@ -485,6 +493,8 @@ func TestConvertClaudeRequestToAntigravity_TrailingUnsignedThinking_Removed(t *t
 }
 
 func TestConvertClaudeRequestToAntigravity_TrailingSignedThinking_Kept(t *testing.T) {
+	cache.ClearSignatureCache("")
+
 	// Last assistant message ends with signed thinking block - should be kept
 	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
 	thinkingText := "Valid thinking..."

internal/translator/antigravity/gemini/antigravity_gemini_request.go

@@ -99,44 +99,36 @@ func ConvertGeminiRequestToAntigravity(modelName string, inputRawJSON []byte, _
 	}
 
 	// Gemini-specific handling for non-Claude models:
-	// - Remove thinking parts entirely.
 	// - Add skip_thought_signature_validator to functionCall parts so upstream can bypass signature validation.
+	// - Also mark thinking parts with the same sentinel when present (we keep the parts; we only annotate them).
 	if !strings.Contains(modelName, "claude") {
 		const skipSentinel = "skip_thought_signature_validator"
 
 		gjson.GetBytes(rawJSON, "request.contents").ForEach(func(contentIdx, content gjson.Result) bool {
-			if content.Get("role").String() != "model" {
+			if content.Get("role").String() == "model" {
-				return true
+				// First pass: collect indices of thinking parts to mark with skip sentinel
-			}
+				var thinkingIndicesToSkipSignature []int64
-			partsResult := content.Get("parts")
+				content.Get("parts").ForEach(func(partIdx, part gjson.Result) bool {
-			if !partsResult.IsArray() {
+					// Collect indices of thinking blocks to mark with skip sentinel
-				return true
-			}
-
-			parts := partsResult.Array()
-			newParts := make([]interface{}, 0, len(parts))
-			for _, part := range parts {
 					if part.Get("thought").Bool() {
-					continue
+						thinkingIndicesToSkipSignature = append(thinkingIndicesToSkipSignature, partIdx.Int())
 					}
-
+					// Add skip sentinel to functionCall parts
-				partRaw := part.Raw
 					if part.Get("functionCall").Exists() {
 						existingSig := part.Get("thoughtSignature").String()
 						if existingSig == "" || len(existingSig) < 50 {
-						updatedPart, errSet := sjson.Set(partRaw, "thoughtSignature", skipSentinel)
+							rawJSON, _ = sjson.SetBytes(rawJSON, fmt.Sprintf("request.contents.%d.parts.%d.thoughtSignature", contentIdx.Int(), partIdx.Int()), skipSentinel)
-						if errSet != nil {
-							log.WithError(errSet).Debug("failed to set thoughtSignature on functionCall part")
-						} else {
-							partRaw = updatedPart
-						}
 						}
 					}
+					return true
+				})
 
-				newParts = append(newParts, gjson.Parse(partRaw).Value())
+				// Add skip_thought_signature_validator sentinel to thinking blocks in reverse order to preserve indices
+				for i := len(thinkingIndicesToSkipSignature) - 1; i >= 0; i-- {
+					idx := thinkingIndicesToSkipSignature[i]
+					rawJSON, _ = sjson.SetBytes(rawJSON, fmt.Sprintf("request.contents.%d.parts.%d.thoughtSignature", contentIdx.Int(), idx), skipSentinel)
+				}
 			}
-
-			rawJSON, _ = sjson.SetBytes(rawJSON, fmt.Sprintf("request.contents.%d.parts", contentIdx.Int()), newParts)
 			return true
 		})
 	}

internal/translator/antigravity/gemini/antigravity_gemini_request_test.go

@@ -62,40 +62,6 @@ func TestConvertGeminiRequestToAntigravity_AddSkipSentinelToFunctionCall(t *test
 	}
 }
 
-func TestConvertGeminiRequestToAntigravity_RemoveThinkingBlocks(t *testing.T) {
-	// Thinking blocks should be removed entirely for Gemini
-	validSignature := "abc123validSignature1234567890123456789012345678901234567890"
-	inputJSON := []byte(fmt.Sprintf(`{
-		"model": "gemini-3-pro-preview",
-		"contents": [
-			{
-				"role": "model",
-				"parts": [
-					{"thought": true, "text": "Thinking...", "thoughtSignature": "%s"},
-					{"text": "Here is my response"}
-				]
-			}
-		]
-	}`, validSignature))
-
-	output := ConvertGeminiRequestToAntigravity("gemini-3-pro-preview", inputJSON, false)
-	outputStr := string(output)
-
-	// Check that thinking block is removed
-	parts := gjson.Get(outputStr, "request.contents.0.parts").Array()
-	if len(parts) != 1 {
-		t.Fatalf("Expected 1 part (thinking removed), got %d", len(parts))
-	}
-
-	// Only text part should remain
-	if parts[0].Get("thought").Bool() {
-		t.Error("Thinking block should be removed for Gemini")
-	}
-	if parts[0].Get("text").String() != "Here is my response" {
-		t.Errorf("Expected text 'Here is my response', got '%s'", parts[0].Get("text").String())
-	}
-}
-
 func TestConvertGeminiRequestToAntigravity_ParallelFunctionCalls(t *testing.T) {
 	// Multiple functionCalls should all get skip_thought_signature_validator
 	inputJSON := []byte(`{