Hi!
I am having a recurring systemic validation error with the Zapier Model Context Protocol (MCP) server when connected to Claude Desktop. The Google Sheets connector is not working for all tool calls in my session. Every attempted action - including metadata reads (find_spreadsheet, get_spreadsheet_by_id), row actions, and even raw passthroughs (make_api_get_request) - fails immediately with an identical structural validation error before the API payload is even sent.
Exact Error Message Received in Claude:
"The Google Sheets connector is failing on every tool call... [Mentioned above] Every call returns the same validation error regardless of parameters: "needs.<field>.computed" — expected boolean, received null
Additional Context:
- Use case: Setting up a scheduled Claude Cowork task to run on a weekly basis that updates several columns in a Google Sheet based on instructions given.
- The root cause (as described by Claude - a little over my head): “The tool-manifest payload generated by the Zapier MCP server for Google Sheets violates strict JSON schema specifications. It appears the internal authentication or input dependency schema configuration defines a conditional needs.<field>.computed property, but passes a null value instead of a strict boolean (true/false). Because Claude enforces rigid schema validation for incoming tools, it rejects the it entirely.”
- Tried already: Removing/re-adding the Google Sheet app in the Zapier MCP Server; disconnecting and reconnecting the Zapier Claude connector; isolating the
Any insights or other troubleshooting ideas would be appreciated.
Thanks!!
