MongoClaw, A mutation runtime for MongoDB with write-time agent safety

Hacker News

Share card

MongoClaw, A mutation runtime for MongoDB with write-time agent safety

I built MongoClaw because every AI enrichment pipeline I've seen hits the same concurrency bug nobody talks about. Your agent reads a document at t0. Inference takes 2 seconds. At t1, another process updates that document. At t2, the agent writes back — silently overwriting live data with output generated from a stale snapshot. Clean 200 OK. No error. That's not a prompt problem. It's a write-safety problem. MongoClaw solves it by capturing version + content hash at dispatch time and issuing a conditional write that only succeeds if the source record still matches. Stale payload? Write suppressed, reason classified, execution record persisted. It also handles: * Idempotent replay protection across all write strategies * Loop detection via agent-origin metadata * In-band policy evaluation (enrich/block/tag) after inference and before mutation Agents are declared in YAML. The runtime handles change stream ingestion, Redis-backed queuing, async execution, schema validation, and auditable writebacks. It also works with external agent endpoints — normalising heterogeneous response formats into the same execution contract. Would appreciate feedback on the write-safety mechanism specifically — curious if others have hit this problem differently.