diff --git a/internal/runtime/executor/antigravity_executor_buildrequest_test.go b/internal/runtime/executor/antigravity_executor_buildrequest_test.go
index c5cba4ee..27dbeca4 100644
--- a/internal/runtime/executor/antigravity_executor_buildrequest_test.go
+++ b/internal/runtime/executor/antigravity_executor_buildrequest_test.go
@@ -59,6 +59,7 @@ func buildRequestBodyFromPayload(t *testing.T, modelName string) map[string]any
 										"properties": {
 											"mode": {
 												"type": "string",
+												"deprecated": true,
 												"enum": ["a", "b"],
 												"enumTitles": ["A", "B"]
 											}
@@ -156,4 +157,7 @@ func assertSchemaSanitizedAndPropertyPreserved(t *testing.T, params map[string]a
 	if _, ok := mode["enumTitles"]; ok {
 		t.Fatalf("enumTitles should be removed from nested schema")
 	}
+	if _, ok := mode["deprecated"]; ok {
+		t.Fatalf("deprecated should be removed from nested schema")
+	}
 }
diff --git a/internal/util/gemini_schema.go b/internal/util/gemini_schema.go
index b8d07bf4..8617b846 100644
--- a/internal/util/gemini_schema.go
+++ b/internal/util/gemini_schema.go
@@ -430,7 +430,7 @@ func removeUnsupportedKeywords(jsonStr string) string {
 	keywords := append(unsupportedConstraints,
 		"$schema", "$defs", "definitions", "const", "$ref", "$id", "additionalProperties",
 		"propertyNames", "patternProperties", // Gemini doesn't support these schema keywords
-		"enumTitles", "prefill", // Claude/OpenCode schema metadata fields unsupported by Gemini
+		"enumTitles", "prefill", "deprecated", // Schema metadata fields unsupported by Gemini
 	)
 
 	deletePaths := make([]string, 0)