What the source did
- He spent an afternoon planning a video editor with Claude Code (Opus 5.5), then told it he was going to bed for 8 hours and to grind on it.
- He woke up to over 200 commits and a working editor. He says it took a day or two of back and forth to make it usable, and he has edited every video with it since.
- Claude drives the editor through a CLI (there's also an MCP server). Anything it changes shows up purple on the timeline, so he only rewatches the parts it touched.
- When he spots something, he leaves a comment on the timeline and tells Claude to go fix it.
- After every video he has Claude review what he changed and fold it into a skill, so it repeats fewer mistakes.
- His lesson: the slowest part of editing is now watching the video back, so the purple "agent edits" view turned out to be the most important feature.
- It replaces Filmora for his Convex videos. A project is one .tandem JSON file in the video's folder, and old Filmora projects can be imported.
- He isn't taking issues or pull requests. He suggests pointing your agent at the repo and making it your own.
“I woke up to over 200 commits and a working editor.”— Mike Cann (u/cannyshammy), Reddit (r/ClaudeCode)
Summary written by Agent Cookbook from the original post. See the original for the full context. How we source recipes
Our notes
- What it takes
- Claude Code or Codex, a Mac on macOS 15+ (Xcode 26+ to build), his open-source Tandem repo and your own footage.
- Where it breaks
- Rewatching everything instead of just the purple agent edits, keeping his paths and import settings, and expecting him to take pull requests; he wants you to fork it.
- Human checkpoint
- You review every agent edit: changes show up purple on the timeline, and you leave comments for the agent to fix.
- Tools involved
- Claude Code (or Codex), A Mac (macOS 15+, Xcode 26+ to build), ffmpeg (optional)
✓ Verified Source link checked and still live. Notes by Thomas, editor. How we verify
Get their template
Made and published by Mike Cann. Start here; it is their original, not ours.
Repo · by Mike CannTandem, his open-source repoMac only. A CLI and an MCP server let Claude Code or Codex edit the same project you have open. He asks you to fork it and have your agent make it your own instead of sending pull requests.Open it ↗Template · by Mike CannWatch him edit a video with it"This is how I make videos now", on the Convex YouTube channel.Open ↗
Their prompt
From Mike Cann Their exact wording: the setup prompt from his README, to paste into Claude Code, Codex or Cursor. Source ↗
Fork https://github.com/mikecann/tandem to my GitHub account and clone my fork
(if I don't use GitHub, or want to keep my copy private, just clone it instead),
then make it my own. It's one of Mike Cann's personal tools, so read the README
first, change anything specific to his setup to suit mine, then help me get it
running.
Approval rule
🛡
He reviews every agent edit himself: they show up purple on the timeline so he rewatches only those parts. Sending, buying, posting, and deleting always need a human.
Set it up
- Paste his prompt into Claude Code, Codex or Cursor so it forks (or clones) the repo and adapts it to your setup.
- Or set it up by hand on macOS 15+ with Xcode 26+: clone the repo, run bash setup_mac.sh, then bash install.sh.
- install.sh links the Tandem skill into ~/.claude/skills and ~/.agents/skills, so Claude Code and Codex know how to edit a .tandem project.
- In a video folder, run tandem new Video.tandem, then tandem app Video.tandem to open the editor.
- Ask your agent to make an edit, then rewatch only the purple parts it changed.
- Leave timeline comments for anything to fix and tell the agent to go fix them.
- After each video, have the agent review your changes and fold them into the skill.
Common failures
⚠
- Expecting it to run anywhere. It's Mac only and needs macOS 15+ and Xcode 26+ to build.
- Rewatching the whole video after every agent pass. The purple edits are there so you only check what changed.
- Sending him pull requests. He isn't taking them; fork it and make it yours.
- Keeping his settings. Some import recipes have paths for his own videos, so change them for your footage.
Variations
- Use MCP instead of the CLI: claude mcp add tandem with the tandem mcp command from his README.
- Import an agent-written edit list (EDL) with tandem import edl.
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