# Readback

- **Event:** [Agents in Context Toronto: a MongoDB Hackathon](https://cerebralvalley.ai/e/mongodb-toronto-hackathon)
- **When:** Sat, Nov 14 at 9:00 AM – 9:00 PM (EST)
- **Where:** Toronto, Canada
- **Team:** [Bobber Cheng](https://cerebralvalley.ai/u/bobber)
- **GitHub:** https://github.com/bobbercheng/readback
- **Demo video:** https://youtu.be/jfFL7y8Fb38
- **Gallery:** https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/14

Readback is an agent for long, multi-step jobs that cross systems and people it does not control. It never marks a step done until a second source confirms it. Every step is a document in MongoDB Atlas whose validator rejects “verified” without evidence. After a crash the worker checks the outside system by its own reference before it resends, so nothing is done twice. A LangGraph planner (observe, plan, guard) proposes each move and can hold an irreversible step when something a person says raises a risk; it can never mark anything verified. Past failures live in Atlas Vector Search with automated embedding and become preconditions on the next job. When a step depends on a phone call, an ElevenLabs voice agent makes it, repeats back what it heard, and code checks the answer against the original request.

The demo applies this to one job: a supplier wire payment. Killed mid-submission, the agent restarts and leaves one wire at the bank, not two. On the call, a wrong digit read back by the bank is caught before release. A person approves the release, and the supplier’s receipt, picked up by a change stream, closes the case. The same core fits any work where “done” is something a person or another system told you: insurance claims, vendor onboarding, permit applications, refunds, purchase orders. The bank portal and all data in the demo are a test rig built today.

## More from Agents in Context Toronto: a MongoDB Hackathon

- [ALabs](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/11)
- [Wilco ATC](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/12)
- [ERS](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/13)
- [Countersign](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/15)
- [PromptForge](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/16)
- [Solo Yolo](https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/17)

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Markdown version of https://cerebralvalley.ai/e/mongodb-toronto-hackathon/hackathon/gallery/14. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt