# Cmux Capture

Screenshot or record a cmux window from the CLI, for a pull request, a bug report, or...

- Repository: https://github.com/manaflow-ai/cmux (28635 stars)
- Category: Design
- License: see repository
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add manaflow-ai/cmux --skill cmux-capture -g -a claude-code -y`
Codex: `npx skills add manaflow-ai/cmux --skill cmux-capture -g -a codex -y`
Cursor: `npx skills add manaflow-ai/cmux --skill cmux-capture -g -a cursor -y`
Gemini CLI: `npx skills add manaflow-ai/cmux --skill cmux-capture -g -a gemini-cli -y`

## Description

Screenshot or record a cmux window from the CLI, for a pull request, a bug report, or to see what the app actually looks like right now. Use when a change is visual, when a drag or an animation cannot be described in text, or when a reviewer needs evidence rather than a claim.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Screenshots and clips of cmux

`cmux shot` writes a png or a jpeg of a cmux window. `cmux record` writes an mp4
or a gif of one. Both capture only cmux's own windows, both go through the
same permission-free path, and both work in a release build and inside CI. No
Screen Recording permission is involved and none is ever requested.

```bash
cmux shot --label settings-sheet                  # png of the frontmost window
cmux shot --jpg --max-width 1200 --out ~/before.jpg
cmux record start --gif --max-seconds 8 --label sidebar-drag
cmux record note "dragging the workspace"         # caption, drawn into the clip
cmux record stop
```

`shot` prints `<width>x<height> <bytes> <path>`. `record` prints
`<id> <state> <frames> <path>`. Both take `--json` for the whole response.

## Which one

Take a screenshot when the thing is still: a sheet, a menu, a layout, a label,
a color. Record when the thing is a change over time: a drag, an animation, a
reorder, two views settling in an order, a spinner that should stop. A
screenshot of a drag shows nothing, and a clip of a static sheet is a large file
a reviewer has to click to play.

## Working from a clip to a still

`--region x,y,w,h` is the same rectangle in both commands, in window points from
the window's top left. So a detail noticed in a clip can be shot with the same
four numbers:

```bash
cmux record start --region 0,0,420,900 --max-seconds 6   # watch the sidebar
cmux shot --region 0,0,420,900 --label sidebar-final     # keep the end state
```

## Notes for an agent recording its own cmux

The rest: https://github.com/manaflow-ai/cmux/blob/HEAD/skills/cmux-capture/SKILL.md