- Rewrite MCP server using rmcp SDK with typed tool routing — execute_sql and psql_config are now proper MCP tools with JsonSchema parameter validation, replacing the hand-rolled JSON-RPC framing that required agents to know the wire format
- Add hint field to CLI error outputs, giving agents actionable next-step suggestions when argument parsing or startup fails
- Improve result_too_large error message to suggest stream_rows=true as the primary remedy, making the retry path clearer for agents hitting inline row/byte limits