google-calendar MCP server turned down — productivity plugin broken

Problem

The google-calendar MCP connection used by the productivity plugin stopped working today (2026-04-17). When Claude Code tries to connect, the MCP server returns a "Server Turned Down" page.

Error message

Server Turned Down
This MCP server has been turned down.

Please use https://calendarmcp.googleapis.com/mcp/v1 instead.

The error page was served from gcal.mcp.claude.com (the install URL used by the plugin).

Root cause

The original MCP server at gcal.mcp.claude.com has been shut down. The suggested replacement endpoint (https://calendarmcp.googleapis.com/mcp/v1) does not support dynamic client registration, which Claude Code requires for OAuth-based MCP servers. This means there is currently no path to reconnect to Google Calendar through this plugin.

Impact

The productivity plugin's Google Calendar integration is completely broken. Any skills or briefings that depend on calendar data (e.g., daily briefings, meeting context) will fail silently or error.

Steps to reproduce

1. Install the productivity plugin in Claude Code
2. Attempt to connect the google-calendar MCP server
3. See "Failed to reconnect to google-calendar" error and the "Server Turned Down" page

Expected behavior

The plugin should either:

• Point to an updated MCP endpoint that supports dynamic client registration, or
• Surface a clear migration guide explaining how to reconnect using the new https://calendarmcp.googleapis.com/mcp/v1 endpoint (including how to handle the auth flow without dynamic client registration)

Environment

• Claude Code version: current (as of 2026-04-17)
• Platform: macOS