diff --git a/open-sse/translator/formats/gemini.js b/open-sse/translator/formats/gemini.js
index 8fdfac8d..bf6c4586 100644
--- a/open-sse/translator/formats/gemini.js
+++ b/open-sse/translator/formats/gemini.js
@@ -21,7 +21,7 @@ export const UNSUPPORTED_SCHEMA_CONSTRAINTS = [
   // Dependency keywords (not supported)
   "dependencies", "dependentSchemas", "dependentRequired",
   // Other unsupported keywords
-  "title", "optional", "if", "then", "else", "contentMediaType", "contentEncoding",
+  "title", "optional", "deprecated", "if", "then", "else", "contentMediaType", "contentEncoding",
   // UI/Styling properties (from Cursor tools - NOT JSON Schema standard)
   "cornerRadius", "fillColor", "fontFamily", "fontSize", "fontWeight",
   "gap", "padding", "strokeColor", "strokeThickness", "textColor"