Merge pull request #611 from soilSpoon/feature/antigravity

feat(antigravity): Improve Claude model compatibility

internal/util/claude_model.go

@@ -0,0 +1,10 @@
+package util
+
+import "strings"
+
+// IsClaudeThinkingModel checks if the model is a Claude thinking model
+// that requires the interleaved-thinking beta header.
+func IsClaudeThinkingModel(model string) bool {
+	lower := strings.ToLower(model)
+	return strings.Contains(lower, "claude") && strings.Contains(lower, "thinking")
+}

internal/util/claude_model_test.go

@@ -0,0 +1,41 @@
+package util
+
+import "testing"
+
+func TestIsClaudeThinkingModel(t *testing.T) {
+	tests := []struct {
+		name     string
+		model    string
+		expected bool
+	}{
+		// Claude thinking models - should return true
+		{"claude-sonnet-4-5-thinking", "claude-sonnet-4-5-thinking", true},
+		{"claude-opus-4-5-thinking", "claude-opus-4-5-thinking", true},
+		{"Claude-Sonnet-Thinking uppercase", "Claude-Sonnet-4-5-Thinking", true},
+		{"claude thinking mixed case", "Claude-THINKING-Model", true},
+
+		// Non-thinking Claude models - should return false
+		{"claude-sonnet-4-5 (no thinking)", "claude-sonnet-4-5", false},
+		{"claude-opus-4-5 (no thinking)", "claude-opus-4-5", false},
+		{"claude-3-5-sonnet", "claude-3-5-sonnet-20240620", false},
+
+		// Non-Claude models - should return false
+		{"gemini-3-pro-preview", "gemini-3-pro-preview", false},
+		{"gemini-thinking model", "gemini-3-pro-thinking", false}, // not Claude
+		{"gpt-4o", "gpt-4o", false},
+		{"empty string", "", false},
+
+		// Edge cases
+		{"thinking without claude", "thinking-model", false},
+		{"claude without thinking", "claude-model", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := IsClaudeThinkingModel(tt.model)
+			if result != tt.expected {
+				t.Errorf("IsClaudeThinkingModel(%q) = %v, expected %v", tt.model, result, tt.expected)
+			}
+		})
+	}
+}

internal/util/gemini_schema.go

@@ -12,10 +12,10 @@ import (
 
 var gjsonPathKeyReplacer = strings.NewReplacer(".", "\\.", "*", "\\*", "?", "\\?")
 
-// CleanJSONSchemaForGemini transforms a JSON schema to be compatible with Gemini/Antigravity API.
+// CleanJSONSchemaForAntigravity transforms a JSON schema to be compatible with Antigravity API.
 // It handles unsupported keywords, type flattening, and schema simplification while preserving
 // semantic information as description hints.
-func CleanJSONSchemaForGemini(jsonStr string) string {
+func CleanJSONSchemaForAntigravity(jsonStr string) string {
 	// Phase 1: Convert and add hints
 	jsonStr = convertRefsToHints(jsonStr)
 	jsonStr = convertConstToEnum(jsonStr)
@@ -32,6 +32,9 @@ func CleanJSONSchemaForGemini(jsonStr string) string {
 	jsonStr = removeUnsupportedKeywords(jsonStr)
 	jsonStr = cleanupRequiredFields(jsonStr)
 
+	// Phase 4: Add placeholder for empty object schemas (Claude VALIDATED mode requirement)
+	jsonStr = addEmptySchemaPlaceholder(jsonStr)
+
 	return jsonStr
 }
 
@@ -105,7 +108,8 @@ func addAdditionalPropertiesHints(jsonStr string) string {
 
 var unsupportedConstraints = []string{
 	"minLength", "maxLength", "exclusiveMinimum", "exclusiveMaximum",
-	"pattern", "minItems", "maxItems",
+	"pattern", "minItems", "maxItems", "format",
+	"default", "examples", // Claude rejects these in VALIDATED mode
 }
 
 func moveConstraintsToDescription(jsonStr string) string {
@@ -339,6 +343,52 @@ func cleanupRequiredFields(jsonStr string) string {
 	return jsonStr
 }
 
+// addEmptySchemaPlaceholder adds a placeholder "reason" property to empty object schemas.
+// Claude VALIDATED mode requires at least one property in tool schemas.
+func addEmptySchemaPlaceholder(jsonStr string) string {
+	// Find all "type" fields
+	paths := findPaths(jsonStr, "type")
+
+	// Process from deepest to shallowest (to handle nested objects properly)
+	sortByDepth(paths)
+
+	for _, p := range paths {
+		typeVal := gjson.Get(jsonStr, p)
+		if typeVal.String() != "object" {
+			continue
+		}
+
+		// Get the parent path (the object containing "type")
+		parentPath := trimSuffix(p, ".type")
+
+		// Check if properties exists and is empty or missing
+		propsPath := joinPath(parentPath, "properties")
+		propsVal := gjson.Get(jsonStr, propsPath)
+
+		needsPlaceholder := false
+		if !propsVal.Exists() {
+			// No properties field at all
+			needsPlaceholder = true
+		} else if propsVal.IsObject() && len(propsVal.Map()) == 0 {
+			// Empty properties object
+			needsPlaceholder = true
+		}
+
+		if needsPlaceholder {
+			// Add placeholder "reason" property
+			reasonPath := joinPath(propsPath, "reason")
+			jsonStr, _ = sjson.Set(jsonStr, reasonPath+".type", "string")
+			jsonStr, _ = sjson.Set(jsonStr, reasonPath+".description", "Brief explanation of why you are calling this tool")
+
+			// Add to required array
+			reqPath := joinPath(parentPath, "required")
+			jsonStr, _ = sjson.Set(jsonStr, reqPath, []string{"reason"})
+		}
+	}
+
+	return jsonStr
+}
+
 // --- Helpers ---
 
 func findPaths(jsonStr, field string) []string {

internal/util/gemini_schema_test.go

@@ -5,9 +5,11 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+
+	"github.com/tidwall/gjson"
 )
 
-func TestCleanJSONSchemaForGemini_ConstToEnum(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_ConstToEnum(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -28,11 +30,11 @@ func TestCleanJSONSchemaForGemini_ConstToEnum(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_TypeFlattening_Nullable(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_TypeFlattening_Nullable(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -60,11 +62,11 @@ func TestCleanJSONSchemaForGemini_TypeFlattening_Nullable(t *testing.T) {
 		"required": ["other"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_ConstraintsToDescription(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_ConstraintsToDescription(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -81,7 +83,7 @@ func TestCleanJSONSchemaForGemini_ConstraintsToDescription(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	// minItems should be REMOVED and moved to description
 	if strings.Contains(result, `"minItems"`) {
@@ -100,7 +102,7 @@ func TestCleanJSONSchemaForGemini_ConstraintsToDescription(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_AnyOfFlattening_SmartSelection(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AnyOfFlattening_SmartSelection(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -131,11 +133,11 @@ func TestCleanJSONSchemaForGemini_AnyOfFlattening_SmartSelection(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_OneOfFlattening(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_OneOfFlattening(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -158,11 +160,11 @@ func TestCleanJSONSchemaForGemini_OneOfFlattening(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_AllOfMerging(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AllOfMerging(t *testing.T) {
 	input := `{
 		"type": "object",
 		"allOf": [
@@ -190,11 +192,11 @@ func TestCleanJSONSchemaForGemini_AllOfMerging(t *testing.T) {
 		"required": ["a", "b"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_RefHandling(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_RefHandling(t *testing.T) {
 	input := `{
 		"definitions": {
 			"User": {
@@ -210,21 +212,29 @@ func TestCleanJSONSchemaForGemini_RefHandling(t *testing.T) {
 		}
 	}`
 
+	// After $ref is converted to placeholder object, empty schema placeholder is also added
 	expected := `{
 		"type": "object",
 		"properties": {
 			"customer": {
 				"type": "object",
-				"description": "See: User"
+				"description": "See: User",
+				"properties": {
+					"reason": {
+						"type": "string",
+						"description": "Brief explanation of why you are calling this tool"
+					}
+				},
+				"required": ["reason"]
 			}
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_RefHandling_DescriptionEscaping(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_RefHandling_DescriptionEscaping(t *testing.T) {
 	input := `{
 		"definitions": {
 			"User": {
@@ -243,21 +253,29 @@ func TestCleanJSONSchemaForGemini_RefHandling_DescriptionEscaping(t *testing.T)
 		}
 	}`
 
+	// After $ref is converted, empty schema placeholder is also added
 	expected := `{
 		"type": "object",
 		"properties": {
 			"customer": {
 				"type": "object",
-				"description": "He said \"hi\"\\nsecond line (See: User)"
+				"description": "He said \"hi\"\\nsecond line (See: User)",
+				"properties": {
+					"reason": {
+						"type": "string",
+						"description": "Brief explanation of why you are calling this tool"
+					}
+				},
+				"required": ["reason"]
 			}
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_CyclicRefDefaults(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_CyclicRefDefaults(t *testing.T) {
 	input := `{
 		"definitions": {
 			"Node": {
@@ -270,7 +288,7 @@ func TestCleanJSONSchemaForGemini_CyclicRefDefaults(t *testing.T) {
 		"$ref": "#/definitions/Node"
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	var resMap map[string]interface{}
 	json.Unmarshal([]byte(result), &resMap)
@@ -285,7 +303,7 @@ func TestCleanJSONSchemaForGemini_CyclicRefDefaults(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_RequiredCleanup(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_RequiredCleanup(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -304,11 +322,11 @@ func TestCleanJSONSchemaForGemini_RequiredCleanup(t *testing.T) {
 		"required": ["a", "b"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_AllOfMerging_DotKeys(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AllOfMerging_DotKeys(t *testing.T) {
 	input := `{
 		"type": "object",
 		"allOf": [
@@ -336,11 +354,11 @@ func TestCleanJSONSchemaForGemini_AllOfMerging_DotKeys(t *testing.T) {
 		"required": ["my.param", "b"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_PropertyNameCollision(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_PropertyNameCollision(t *testing.T) {
 	// A tool has an argument named "pattern" - should NOT be treated as a constraint
 	input := `{
 		"type": "object",
@@ -364,7 +382,7 @@ func TestCleanJSONSchemaForGemini_PropertyNameCollision(t *testing.T) {
 		"required": ["pattern"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 
 	var resMap map[string]interface{}
@@ -375,7 +393,7 @@ func TestCleanJSONSchemaForGemini_PropertyNameCollision(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_DotKeys(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_DotKeys(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -389,7 +407,7 @@ func TestCleanJSONSchemaForGemini_DotKeys(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	var resMap map[string]interface{}
 	if err := json.Unmarshal([]byte(result), &resMap); err != nil {
@@ -414,7 +432,7 @@ func TestCleanJSONSchemaForGemini_DotKeys(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_AnyOfAlternativeHints(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AnyOfAlternativeHints(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -428,7 +446,7 @@ func TestCleanJSONSchemaForGemini_AnyOfAlternativeHints(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if !strings.Contains(result, "Accepts:") {
 		t.Errorf("Expected alternative types hint, got: %s", result)
@@ -438,7 +456,7 @@ func TestCleanJSONSchemaForGemini_AnyOfAlternativeHints(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_NullableHint(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_NullableHint(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -450,7 +468,7 @@ func TestCleanJSONSchemaForGemini_NullableHint(t *testing.T) {
 		"required": ["name"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if !strings.Contains(result, "(nullable)") {
 		t.Errorf("Expected nullable hint, got: %s", result)
@@ -460,7 +478,7 @@ func TestCleanJSONSchemaForGemini_NullableHint(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_TypeFlattening_Nullable_DotKey(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_TypeFlattening_Nullable_DotKey(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -488,11 +506,11 @@ func TestCleanJSONSchemaForGemini_TypeFlattening_Nullable_DotKey(t *testing.T) {
 		"required": ["other"]
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_EnumHint(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_EnumHint(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -504,7 +522,7 @@ func TestCleanJSONSchemaForGemini_EnumHint(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if !strings.Contains(result, "Allowed:") {
 		t.Errorf("Expected enum values hint, got: %s", result)
@@ -514,7 +532,7 @@ func TestCleanJSONSchemaForGemini_EnumHint(t *testing.T) {
 	}
 }
 
-func TestCleanJSONSchemaForGemini_AdditionalPropertiesHint(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AdditionalPropertiesHint(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -523,14 +541,14 @@ func TestCleanJSONSchemaForGemini_AdditionalPropertiesHint(t *testing.T) {
 		"additionalProperties": false
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if !strings.Contains(result, "No extra properties allowed") {
 		t.Errorf("Expected additionalProperties hint, got: %s", result)
 	}
 }
 
-func TestCleanJSONSchemaForGemini_AnyOfFlattening_PreservesDescription(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_AnyOfFlattening_PreservesDescription(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -554,11 +572,11 @@ func TestCleanJSONSchemaForGemini_AnyOfFlattening_PreservesDescription(t *testin
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 	compareJSON(t, expected, result)
 }
 
-func TestCleanJSONSchemaForGemini_SingleEnumNoHint(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_SingleEnumNoHint(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -569,14 +587,14 @@ func TestCleanJSONSchemaForGemini_SingleEnumNoHint(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if strings.Contains(result, "Allowed:") {
 		t.Errorf("Single value enum should not add Allowed hint, got: %s", result)
 	}
 }
 
-func TestCleanJSONSchemaForGemini_MultipleNonNullTypes(t *testing.T) {
+func TestCleanJSONSchemaForAntigravity_MultipleNonNullTypes(t *testing.T) {
 	input := `{
 		"type": "object",
 		"properties": {
@@ -586,7 +604,7 @@ func TestCleanJSONSchemaForGemini_MultipleNonNullTypes(t *testing.T) {
 		}
 	}`
 
-	result := CleanJSONSchemaForGemini(input)
+	result := CleanJSONSchemaForAntigravity(input)
 
 	if !strings.Contains(result, "Accepts:") {
 		t.Errorf("Expected multiple types hint, got: %s", result)
@@ -676,3 +694,190 @@ func compareJSON(t *testing.T, expectedJSON, actualJSON string) {
 		t.Errorf("JSON mismatch:\nExpected:\n%s\n\nActual:\n%s", string(expBytes), string(actBytes))
 	}
 }
+
+// ============================================================================
+// Empty Schema Placeholder Tests
+// ============================================================================
+
+func TestCleanJSONSchemaForAntigravity_EmptySchemaPlaceholder(t *testing.T) {
+	// Empty object schema with no properties should get a placeholder
+	input := `{
+		"type": "object"
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// Should have placeholder property added
+	if !strings.Contains(result, `"reason"`) {
+		t.Errorf("Empty schema should have 'reason' placeholder property, got: %s", result)
+	}
+	if !strings.Contains(result, `"required"`) {
+		t.Errorf("Empty schema should have 'required' with 'reason', got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_EmptyPropertiesPlaceholder(t *testing.T) {
+	// Object with empty properties object
+	input := `{
+		"type": "object",
+		"properties": {}
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// Should have placeholder property added
+	if !strings.Contains(result, `"reason"`) {
+		t.Errorf("Empty properties should have 'reason' placeholder, got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_NonEmptySchemaUnchanged(t *testing.T) {
+	// Schema with properties should NOT get placeholder
+	input := `{
+		"type": "object",
+		"properties": {
+			"name": {"type": "string"}
+		},
+		"required": ["name"]
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// Should NOT have placeholder property
+	if strings.Contains(result, `"reason"`) {
+		t.Errorf("Non-empty schema should NOT have 'reason' placeholder, got: %s", result)
+	}
+	// Original properties should be preserved
+	if !strings.Contains(result, `"name"`) {
+		t.Errorf("Original property 'name' should be preserved, got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_NestedEmptySchema(t *testing.T) {
+	// Nested empty object in items should also get placeholder
+	input := `{
+		"type": "object",
+		"properties": {
+			"items": {
+				"type": "array",
+				"items": {
+					"type": "object"
+				}
+			}
+		}
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// Nested empty object should also get placeholder
+	// Check that the nested object has a reason property
+	parsed := gjson.Parse(result)
+	nestedProps := parsed.Get("properties.items.items.properties")
+	if !nestedProps.Exists() || !nestedProps.Get("reason").Exists() {
+		t.Errorf("Nested empty object should have 'reason' placeholder, got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_EmptySchemaWithDescription(t *testing.T) {
+	// Empty schema with description should preserve description and add placeholder
+	input := `{
+		"type": "object",
+		"description": "An empty object"
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// Should have both description and placeholder
+	if !strings.Contains(result, `"An empty object"`) {
+		t.Errorf("Description should be preserved, got: %s", result)
+	}
+	if !strings.Contains(result, `"reason"`) {
+		t.Errorf("Empty schema should have 'reason' placeholder, got: %s", result)
+	}
+}
+
+// ============================================================================
+// Format field handling (ad-hoc patch removal)
+// ============================================================================
+
+func TestCleanJSONSchemaForAntigravity_FormatFieldRemoval(t *testing.T) {
+	// format:"uri" should be removed and added as hint
+	input := `{
+		"type": "object",
+		"properties": {
+			"url": {
+				"type": "string",
+				"format": "uri",
+				"description": "A URL"
+			}
+		}
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// format should be removed
+	if strings.Contains(result, `"format"`) {
+		t.Errorf("format field should be removed, got: %s", result)
+	}
+	// hint should be added to description
+	if !strings.Contains(result, "format: uri") {
+		t.Errorf("format hint should be added to description, got: %s", result)
+	}
+	// original description should be preserved
+	if !strings.Contains(result, "A URL") {
+		t.Errorf("Original description should be preserved, got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_FormatFieldNoDescription(t *testing.T) {
+	// format without description should create description with hint
+	input := `{
+		"type": "object",
+		"properties": {
+			"email": {
+				"type": "string",
+				"format": "email"
+			}
+		}
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// format should be removed
+	if strings.Contains(result, `"format"`) {
+		t.Errorf("format field should be removed, got: %s", result)
+	}
+	// hint should be added
+	if !strings.Contains(result, "format: email") {
+		t.Errorf("format hint should be added, got: %s", result)
+	}
+}
+
+func TestCleanJSONSchemaForAntigravity_MultipleFormats(t *testing.T) {
+	// Multiple format fields should all be handled
+	input := `{
+		"type": "object",
+		"properties": {
+			"url": {"type": "string", "format": "uri"},
+			"email": {"type": "string", "format": "email"},
+			"date": {"type": "string", "format": "date-time"}
+		}
+	}`
+
+	result := CleanJSONSchemaForAntigravity(input)
+
+	// All format fields should be removed
+	if strings.Contains(result, `"format"`) {
+		t.Errorf("All format fields should be removed, got: %s", result)
+	}
+	// All hints should be added
+	if !strings.Contains(result, "format: uri") {
+		t.Errorf("uri format hint should be added, got: %s", result)
+	}
+	if !strings.Contains(result, "format: email") {
+		t.Errorf("email format hint should be added, got: %s", result)
+	}
+	if !strings.Contains(result, "format: date-time") {
+		t.Errorf("date-time format hint should be added, got: %s", result)
+	}
+}

internal/util/thinking_text.go

@@ -0,0 +1,87 @@
+package util
+
+import (
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+// GetThinkingText extracts the thinking text from a content part.
+// Handles various formats:
+// - Simple string: { "thinking": "text" } or { "text": "text" }
+// - Wrapped object: { "thinking": { "text": "text", "cache_control": {...} } }
+// - Gemini-style: { "thought": true, "text": "text" }
+// Returns the extracted text string.
+func GetThinkingText(part gjson.Result) string {
+	// Try direct text field first (Gemini-style)
+	if text := part.Get("text"); text.Exists() && text.Type == gjson.String {
+		return text.String()
+	}
+
+	// Try thinking field
+	thinkingField := part.Get("thinking")
+	if !thinkingField.Exists() {
+		return ""
+	}
+
+	// thinking is a string
+	if thinkingField.Type == gjson.String {
+		return thinkingField.String()
+	}
+
+	// thinking is an object with inner text/thinking
+	if thinkingField.IsObject() {
+		if inner := thinkingField.Get("text"); inner.Exists() && inner.Type == gjson.String {
+			return inner.String()
+		}
+		if inner := thinkingField.Get("thinking"); inner.Exists() && inner.Type == gjson.String {
+			return inner.String()
+		}
+	}
+
+	return ""
+}
+
+// GetThinkingTextFromJSON extracts thinking text from a raw JSON string.
+func GetThinkingTextFromJSON(jsonStr string) string {
+	return GetThinkingText(gjson.Parse(jsonStr))
+}
+
+// SanitizeThinkingPart normalizes a thinking part to a canonical form.
+// Strips cache_control and other non-essential fields.
+// Returns the sanitized part as JSON string.
+func SanitizeThinkingPart(part gjson.Result) string {
+	// Gemini-style: { thought: true, text, thoughtSignature }
+	if part.Get("thought").Bool() {
+		result := `{"thought":true}`
+		if text := GetThinkingText(part); text != "" {
+			result, _ = sjson.Set(result, "text", text)
+		}
+		if sig := part.Get("thoughtSignature"); sig.Exists() && sig.Type == gjson.String {
+			result, _ = sjson.Set(result, "thoughtSignature", sig.String())
+		}
+		return result
+	}
+
+	// Anthropic-style: { type: "thinking", thinking, signature }
+	if part.Get("type").String() == "thinking" || part.Get("thinking").Exists() {
+		result := `{"type":"thinking"}`
+		if text := GetThinkingText(part); text != "" {
+			result, _ = sjson.Set(result, "thinking", text)
+		}
+		if sig := part.Get("signature"); sig.Exists() && sig.Type == gjson.String {
+			result, _ = sjson.Set(result, "signature", sig.String())
+		}
+		return result
+	}
+
+	// Not a thinking part, return as-is but strip cache_control
+	return StripCacheControl(part.Raw)
+}
+
+// StripCacheControl removes cache_control and providerOptions from a JSON object.
+func StripCacheControl(jsonStr string) string {
+	result := jsonStr
+	result, _ = sjson.Delete(result, "cache_control")
+	result, _ = sjson.Delete(result, "providerOptions")
+	return result
+}