mem0 stack (phoebe): config is ENV-ONLY — never use POST /configure or dashboard config editor. GET /configure REDACTS secrets, so round-tripping it corrupts the stored pgvector password (broke prod 2026-07-18; fixed by deleting mem0_app.settings row key=config_overrides + docker restart mem0-mem0-api-1; row backup at phoebe:/root/mem0-settings-backup.sql). Correct model names need LiteLLM route prefixes: deepseek/deepseek-v4-flash, nvidia/nemotron-embed-1b-v2 (1536-dim, pinned — swapping embedder invalidates all stored vectors).