Truncated / malformed JSON

malformed-json · Transport & framing

Endpoint (Streamable HTTP)

https://chaos-mcp.thomascdnns.com/s/malformed-json/mcp

On the wire — recorded from a real request

Symptom

what you'll observe

Client errors with 'Unexpected end of JSON input' or a parse error on every call.

Cause

what this reproduces

Response serialization bug, a panic mid-write, or a proxy that truncates the body.

Fix

how you'd resolve it

Marshal the full object before writing; never stream partial JSON; check upstream proxy buffering.

Try it with curl

bash

curl -sS -X POST \
  https://chaos-mcp.thomascdnns.com/s/malformed-json/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"}
    }
  }'