different-ai/openwork · error · SafeProbeFailure

request_id_mismatch

request_id_mismatch

Error message

request_id_mismatch

What it means

parseJsonRpcResult throws SafeProbeFailure("request_id_mismatch") when the response's 'id' does not strictly equal the request id the probe generated. JSON-RPC correlation requires id echo; any mismatch indicates a response for a different request or a tampered/buggy server.

Source

Thrown at apps/server/src/agent-context-cloud-probe.ts:532

    if (line.startsWith(":")) continue;
    const colon = line.indexOf(":");
    const field = colon < 0 ? line : line.slice(0, colon);
    const rawValue = colon < 0 ? "" : line.slice(colon + 1);
    const value = rawValue.startsWith(" ") ? rawValue.slice(1) : rawValue;
    if (field === "event") event = value;
    if (field === "data") data.push(value);
  }
  dispatch();
  if (messages.length !== 1) throw new SafeProbeFailure("invalid_json");
  return messages[0];
}

function parseJsonRpcResult(payload: unknown, requestId: string): Record<string, unknown> {
  if (!isRecord(payload) || payload.jsonrpc !== "2.0") {
    throw new SafeProbeFailure("invalid_jsonrpc_envelope");
  }
  if (Object.hasOwn(payload, "error")) throw new SafeProbeFailure("jsonrpc_error");
  if (payload.id !== requestId) throw new SafeProbeFailure("request_id_mismatch");
  if (!isRecord(payload.result)) throw new SafeProbeFailure("invalid_jsonrpc_envelope");
  return payload.result;
}

function requireSupportedProtocolVersion(initializeResult: Record<string, unknown>): void {
  const version = initializeResult.protocolVersion;
  if (typeof version !== "string" || version.length === 0 || version.length > MAX_PROTOCOL_HEADER_LENGTH) {
    throw new SafeProbeFailure("invalid_jsonrpc_envelope");
  }
  if (version !== MCP_PROTOCOL_VERSION) throw new SafeProbeFailure("unsupported_protocol_version");
}

function validateCatalog(rpcResult: Record<string, unknown>): { toolIds: string[]; totalToolCount: number } {
  if (rpcResult.nextCursor !== undefined && rpcResult.nextCursor !== null) {
    throw new SafeProbeFailure("pagination_unsupported");
  }
  if (!Array.isArray(rpcResult.tools) || rpcResult.tools.length > MAX_TOOL_COUNT) {
    throw new SafeProbeFailure("invalid_catalog");

View on GitHub (pinned to 2b7df46e8a)

Solutions

1. Verify the server echoes the exact 'id' value from the request (same type and value)
2. Test the endpoint with a single sequential request to rule out interleaving bugs
3. Update the server's JSON-RPC implementation to a spec-compliant version
4. Check for proxies that cache or reroute responses between concurrent clients

Example fix

// before (server)
res.write(JSON.stringify({jsonrpc:"2.0",id:"req-1",result})) // request id was 1 (number)
// after
res.write(JSON.stringify({jsonrpc:"2.0",id:requestId,result}))

const echoed = (body as Record<string, unknown> | null)?.id;
if (echoed !== requestId) throw new Error(`response id ${JSON.stringify(echoed)} does not match request id ${JSON.stringify(requestId)}`);

function hasMatchingId(payload: unknown, requestId: unknown): payload is { id: unknown } & Record<string, unknown> {
  return typeof payload === "object" && payload !== null && (payload as Record<string, unknown>).id === requestId;
}

try {
  const result = parseJsonRpcResult(payload, requestId);
} catch (e) {
  if (e instanceof SafeProbeFailure && e.code === "request_id_mismatch") {
    // log both ids and body; treat server as non-compliant or serialized behind a misbehaving proxy
  } else throw e;
}

When it happens

Trigger: Server responds with id: null, omits id, returns a string id where a number was sent (or vice versa), or echoes a stale id.

Common situations: Server implementation reuses or regenerates ids; a multiplexing proxy returns the wrong pending response; server coerces numeric ids to strings; concurrent requests interleaved incorrectly.

Related errors

• invalid_jsonrpc_envelope
• jsonrpc_error
• MCP_INITIALIZE
• MCP_PROVIDER_DECLARED_ERROR
• MCP_HTTP_CONTENT_TYPE

AI-assisted analysis of different-ai/openwork@2b7df46e8a (2026-09-01). Data as JSON: /api/errors/503d4198f2ae670f. Report an issue: GitHub.