Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.narrative.io/llms.txt

Use this file to discover all available pages before exploring further.

Surface: GET /agents/runs/{id}, error.type = "McpProtocol"

​
When this error occurs

The workflow’s McpToolCallActivity sent a JSON-RPC tools/call request and got back a response that:
  • Wasn’t valid JSON, or
  • Had the wrong Content-Type (expected application/json or text/event-stream), or
  • Was JSON but didn’t match JSON-RPC 2.0 (missing jsonrpc, wrong id, structural mismatch),
  • Was a JSON-RPC error with a code outside the documented range that the workflow knows how to classify (-32601 → UnknownTool, -32602 → ToolValidation, anything else → here).
This error is not retried by the workflow — the response is structurally broken, so a retry would hit the same response.

​
How to fix

This is almost always a problem on the MCP server side. Owners of the server should check their logs around the failed call timestamp. The workflow logs include the raw response body for support to inspect.