Brain MCP AmbiguousParameterError on brain_record_verification_result
Diagnosis
asyncpg type inference conflict — 2 = ‘PASS’ text comparison in same query. psql handles fine; only surfaces with asyncpg strict type inference.
Fix
Add ::varchar cast to ambiguous usage: CASE WHEN $2::varchar = ‘PASS’ in /opt/mcp-servers/brain-mcp/src/brain_mcp/tools/verify.py line 91. Rebuild container.