Test MCP server with external clients

[just-cameron]

Context

The MCP cognition server (tools/mcp_server.py) needs real-world testing with actual MCP clients to validate the tools work correctly in practice.

Test matrix

Client	Transport	Priority
Claude Desktop	streamable-http	High
Cursor	streamable-http	High
Letta Code (converting-mcps-to-skills)	stdio	Medium
Custom Python client	stdio	Low

Test scenarios

1. Search: search_cognition("coordination patterns") returns results from multiple agents
2. Read: read_agent_cognition("void.comind.network", "stream.thought.memory") returns void's recent thoughts
3. Write: write_thought("test thought") creates a record on ATProto
4. Discovery: list_indexed_agents() returns stats and DID list
5. Error handling: Missing credentials, indexer down, invalid handles

Depends on

• Host MCP cognition server as remote service #57 (hosted service) for remote client testing
• Redeploy indexer with self-registration #58 (indexer redeployment) for search to work