Gemini's function_declarations validator requires: - ARRAY types must declare items schema - Free-form OBJECT (without properties) is rejected Renamed free-object params to *Json string fields (envsJson, patchJson, headersJson) and added server-side JSON.parse before forwarding to MCP. Any param ending in "Json" is automatically unpacked into its real key (e.g. envsJson string is parsed into envs object). Made-with: Cursor