# usectx

- **Event:** [Built with Opus 4.7: a Claude Code hackathon](https://cerebralvalley.ai/e/built-with-4-7-hackathon)
- **When:** Apr 21 at 12:00 PM – Apr 27 at 2:00 AM (EDT)
- **Where:** Online
- **Team:** [Arth Tyagi](https://cerebralvalley.ai/u/arth)
- **GitHub:** https://github.com/arthtyagi/ctx
- **Demo video:** https://youtu.be/FwuFTUBc2-c
- **Gallery:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery/267

op0 is a creative studio built on ctx, a Managed Agents harness for auditable, self-modifying agents. The user briefs the studio; the agent reaches into a Zod-typed capability registry — twelve MA tools spanning composition (compose.character, compose.score, plus two distinct video paths: compose.video for Remotion-based slideshow stitching and compose.gen_video for generative clips via Replicate Veo / Kling / LTX), workspace control (customize_studio, studio_navigate, studio_run_rig), self-modification (instructions, save_rig, propose_rig), and mail (mail_list, mail_send) — and every durable change is a typed tool call with the user's reason attached.
The key primitive is the rig: a reusable workflow over the same registry the live agent uses. The rig DSL supports {{steps.<id>.blobUrl}} so a video step chains off prior character/score outputs — the built-in music-video rig runs character → score → video deterministically through Vercel WDK and replays into the same audit graph the live agent populates. Capabilities flagged usableInRig are eligible; side-effect tools (mail, navigate) stay live-only.
ctx's digest agent supplies the quantified proof: a coached Managed Agent improves Discord-style digest relevance from 86.0% to 93.6% in the canonical run, including an audited retire-then-upsert belief-revision moment. op0 proves the same substrate becomes a visual, musical, inbox-capable, multi-run studio — runs stack on one canvas, errors trigger one-click recovery, and the timeline editor lets you scrub trim handles to hear the cut as you make it. Same harness, richer surface

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Markdown version of https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery/267. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt