vault-mcp-session-drops-do-not-lose-persisted-data
MCP streamable-HTTP sessions (including vault-mcp) can disconnect mid-session from idle timeout, Traefik network blip, or session-affinity quirks — the same class of transient 421 errors seen with Graphiti. Critically, the vault data on disk at /opt/second-brain/vault/ remains fully intact; only the MCP transport layer drops. Strategy: complete all material vault writes early in a session rather than deferring to session-close phases where a disconnect cannot be recovered.