Correlate JSON-RPC Response to Pending Requesteasy

Correlate JSON-RPC Response to Pending Request

easy Agents in Production 15 min

NumPy allowed · plain Python earns 10 bonus points

Implement request/response correlation by id, the real mechanism an MCP client uses to route an async response back to the code that's waiting for it.

Task

Implement correlate_response(pending_requests, response_id). pending_requests maps request id -> the method name that was called. Return the method name for response_id, or 'unknown' if response_id isn't a pending request.

Function Signature

correlate_response(pending_requests: dict[str, str], response_id: str) -> str

Examples

Example 1: known pending request
Input: pending_requests = {'1': 'tools/call', '2': 'resources/read'}
response_id = '1'
Output: 'tools/call'

Example 2: unknown response id
Input: pending_requests = {'1': 'tools/call'}
response_id = '99'
Output: 'unknown'

Example 3: single pending request
Input: pending_requests = {'a': 'ping'}
response_id = 'a'
Output: 'ping'

Constraints

pending_requests is a dict

Python3Saved ✓

def correlate_response(pending_requests, response_id):

# Your implementation here

pass

Case 1: known pending request

Input: pending_requests = {'1': 'tools/call', '2': 'resources/read'}
response_id = '1'

Expected: 'tools/call'

Case 2: unknown response id

Input: pending_requests = {'1': 'tools/call'}
response_id = '99'

Expected: 'unknown'

Case 3: single pending request

Input: pending_requests = {'a': 'ping'}
response_id = 'a'

Expected: 'ping'