tools/call returns JSON-RPC error

tool-rpc-error · Tools — execution

Endpoint (Streamable HTTP)

https://chaos-mcp.thomascdnns.com/s/tool-rpc-error/mcp

On the wire — recorded from a real request

Symptom

what you'll observe

Instead of a result with isError, the whole call fails with a JSON-RPC error object.

Cause

what this reproduces

The server throws and maps the exception to a protocol error rather than a tool result.

Fix

how you'd resolve it

Decide deliberately: recoverable tool failures → isError result; protocol faults → JSON-RPC error.

Try it with curl

bash

curl -sS -X POST \
  https://chaos-mcp.thomascdnns.com/s/tool-rpc-error/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json' \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
      "protocolVersion": "2024-11-05",
      "capabilities": {},
      "clientInfo": {"name": "curl", "version": "1"}
    }
  }'