Calendar API Tools Fail With Generic Error

[akoenig]

I successfully added the Google Calendar source and the tools are registered and discoverable, but every Calendar API call fails at execution time with only a generic Tool execution failed error. The underlying Google/API/auth error is not surfaced, which makes it hard to diagnose whether this is an OAuth issue, a Google Discovery runtime issue, or a generated-tool execution bug.

Environment

• Client: Hermes Agent
• Executor: Started via executor web
• Calendar source is discoverable and reports 37 tools
• MCP connection itself appears healthy as other tool calls are functional

Steps To Reproduce

From Hermes’ mcp_executor_execute tool, run:

const res = await tools.calendar_api.calendarList.list({ maxResults: 250 });

return JSON.stringify(res, null, 2);

Expected Result

The call should return the authenticated user’s Google Calendar list, or at least return a useful underlying error such as:

• missing OAuth token
• expired token
• insufficient scopes
• Google API 401/403 response
• malformed generated request
• missing source credentials
• Discovery runtime error with details

Actual Result

The call fails with a generic error:

Error: Error: Tool execution failed
    at <anonymous> (executor-quickjs-runtime.js:43)

    at m3H (/$bunfs/root/main.js:337:107586)
    at $j (/$bunfs/root/main.js:337:107865)
    at <anonymous> (/$bunfs/root/main.js:338:2707)
    at processTicksAndRejections (native:7:39)

[akoenig]

The last release was super helpful, @RhysSullivan. Thanks! It helped me realize, thanks to the clear error message output which was introduced in this release, that I hadn’t enabled the Google Calendar API in my GCP project.