Y Combinator · 4× · last seen Aug 12, 2026
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Momentum
QM (Quartermaster) is an open-source multiplayer-capable agent harness for enterprises published by Y Combinator, which YC uses internally in accounting, legal, events, and engineering. The tool runs natively in Slack and on the web, is model- and harness-agnostic (supporting Pi, OpenCode, Codex, and Claude Code), and assigns each employee or room an isolated scope with its own storage, files, credentials, permissions, and sandbox. QM is available under MIT license on GitHub and is self-hosted (Fly.io or AWS) with no hosted SaaS service and no licensing costs—actual costs only arise from cloud infrastructure and model API usage.
Momentum trend
14.05.12.08.
Features
| Autonomy Level | Agent acts with the person's own credentials/permissions; three security postures (Strict/Auto/Dangerous), Strict requires human approval for every tool call, all actions are audited |
| Channels | Slack and web (native integration, same identity across both surfaces) |
| License | MIT License (open source) |
| Modalities | Text-based agent interaction with file, web-app, and browser support (agent browser support, shareable web app artifacts) |
| Platform | Cloud-first, native Slack and web UI; deploys to Fly.io or AWS in the operator's own cloud account |
| Price | Free (MIT license), no paid tier; real costs are only your own cloud hosting (Fly.io/AWS) plus model API usage |
| Release Date | July 31, 2026 (public announcement by Y Combinator) |
| Tool/MCP Integrations | Supports Pi, OpenCode, Codex, and Claude Code as interchangeable harness/model backends; connectors, crons, webhooks, skills, sandbox execution |