✂️ Edit Twin MCP

Your editing twin for Final Cut Pro. Edit Twin lets Claude Code rough-cut your Final Cut Pro projects for you: it cuts retakes, "um"s and dead air, adds your colour look and dialogue sound, and hands you back a new project to finish. Then it learns from how you finish it, so each rough cut gets closer to how you'd have cut it yourself.

Note: Currently tracking what best ASR model for transcripts, captioning via this dashboard

Edit Twin is an independent, free, open-source project. It is not affiliated with, endorsed by, or sponsored by Apple Inc. Final Cut Pro is a trademark of Apple Inc.

What it does

Open a project in Final Cut Pro, then in Claude Code say:

rough cut my open project

1. Reads your edit. It exports the project and transcribes the speech on your Mac. Your video and audio never leave your Mac; Claude sees the transcript and timeline details it needs to plan the cut (see Privacy).

2. Finds what to cut: retakes where you said a line twice (it keeps the better take), stutters ("to new to new tech"), um/uh fillers and pauses.

3. Shows you the plan and waits. Nothing changes until you say OK.

4. Cuts it, then adds your style: your saved colour look on an adjustment clip over the whole edit, and your dialogue sound (gain plus Final Cut's Loudness effect).

5. Sends it back to Final Cut Pro as a new project. Your original is never touched.

It adapts to the format. Reels and shorts get tight jump cuts and a check that the first 3 seconds work as a hook. Landscape vlogs get their own pacing (looser at first, then learned from your hand edits separately from reels), and quiet B-roll, scenery and music moments are never cut as "silence".

Related MCP server: fcp-mcp-server

Captions 💬

caption my open project

Captions are timed to every word on your edit and added as Final Cut Pro titles, in your caption styles:

• Short form: one word (or a few) pops on as you say it, e.g. in a display font at the top of a vertical reel.

• Long form: subtitle lines near the bottom, measured in your font so each line fits the frame and stays comfortable to read.

Set a style up once, either by styling one title by hand in Final Cut (Edit Twin copies its font, size, colour, position and any animation exactly), or by describing it ("one word at a time, Futura, lowercase, near the top, for my reels"). Any font installed on your Mac works; Edit Twin reads the real font names from the font files and remembers the fonts you use, so next time "caption it" is enough. Misheard words are fixed before anything is added, and export_srt writes an .srt for YouTube closed captions.

How it learns your style ✨

After you polish an Edit Twin rough cut by hand, say:

learn from my edit

Edit Twin compares its version with yours, frame by frame against the original footage, and tells you what you did differently:

• which words or retakes you removed or put back,

• how much breathing room you leave before and after words,

• your audio chain (gain, Loudness, Noise Removal, EQ),

• the look on your adjustment clip,

• the fonts in your titles.

It then calibrates its pause detection to match your own trims and saves everything as your style. On the reel Edit Twin was developed with, the calibrated settings overlapped with the creator's own hand trims 72%, compared with 13% for the old loose settings. The rest were creative word-level choices, and those you keep making yourself.

Your style (including caption styles and fonts) lives on your Mac in ~/Movies/Edit Twin/style.json and ~/Movies/Edit Twin/looks/.

Install

You need:

• a Mac with Final Cut Pro (developed on 11.2; FCPXML 1.11 or newer). Apple Silicon is recommended; Intel Macs work but transcribe more slowly,

• Claude Code (needs a Claude subscription or API key),

• Homebrew, which the installer uses to get ffmpeg and Python 3.10+ if they're missing,

• git (macOS offers to install it the first time you run git),

• about 3 GB of free disk space (Python packages plus the speech model).

Then, in Terminal:

git clone https://github.com/alyssasworld/edit-twin-mcp.git
cd edit-twin-mcp
./install.sh

The installer:

• installs ffmpeg and Python 3.12 with Homebrew, only if they're missing,

• sets everything up in a private folder (.venv inside the cloned folder), so it won't touch your other Python stuff,

• installs the Python packages there: the MCP SDK, plus the speech-to-text engines for your Mac (Apple Silicon: parakeet-mlx and mlx-whisper; Intel: faster-whisper) and their dependencies (on Apple Silicon these include PyTorch, NumPy and SciPy, roughly 1 GB),

• prints which speech-to-text engine it will use and why, e.g. Speech-to-text: parakeet (auto: Apple Silicon with Parakeet installed),

• registers Edit Twin with Claude Code for all your projects (claude mcp add --scope user),

• copies the /edit-twin-rough-cut skill to ~/.claude/skills/edit-twin-rough-cut (re-running the installer updates it),

• creates the working folder ~/Movies/Edit Twin.

The first transcription downloads a free speech model from Hugging Face, once, for the engine in use: mlx-community/parakeet-tdt-0.6b-v3 on Apple Silicon, or Whisper large-v3-turbo (about 1.5 GB) where Parakeet isn't used.

Choosing the speech-to-text engine

You don't have to choose: by default (auto) Edit Twin uses Parakeet on Apple Silicon Macs for the languages it knows (English and 24 other European languages), and Whisper on Intel Macs and for any other language. On the author's footage Parakeet caught 80% of um/uh against Whisper's 35%, made fewer word errors and ran ~3.6× faster (benchmark); Whisper punctuates slightly better and knows ~99 languages.

get_style (and the server's log in /mcp) says which engine will run and why.

Names and jargon

Parakeet takes no spelling hints, so names are corrected after transcription, for both engines. Tell Claude the names you say ("Navier-Stokes, POPMART") and it saves them (update_style add_vocabulary): close misspellings ("Popma") and spacing ("Skull Panda") are corrected to them in every transcript, while real words that only look similar are left alone. Corrections that are always right can be saved as exact fixes (add_fixes, or remember_fixes when captioning). Both live in style.json under transcription.

One-time Mac permissions

Open System Settings → Privacy & Security and allow the app you run Claude Code in (Terminal, iTerm, VS Code…):

Quit and reopen that app, start claude, and type /mcp. You should see edit-twin connected.

If your footage is on an external drive, keep it plugged in while editing. macOS may also ask to let Terminal access removable volumes; click Allow.

Things to ask

• "Rough cut my open project. Show me the cuts first."

• "Find my retakes and tell me which take is better."

• "Remove the pauses but keep it a bit looser, it's a vlog."

• "Save the look on my adjustment clip as warm_vlog and use it by default."

• "Put coffee.mov over 0:42 for 3 seconds and add music.m4a under everything at −18 dB."

• "Add chapter markers at each topic change."

• "Caption this reel one word at a time in Futura, lowercase, near the top. Make that my reel style."

• "Save the title at 0:03 as my vlog subtitle style."

• "Caption it" (uses your saved style for the format) · "Export an SRT for YouTube."

• "How loud is this edit?"

• "Learn from my edit."

How it works (for the curious)

Final Cut Pro doesn't let other apps edit a timeline directly, so Edit Twin uses Apple's official interchange format, FCPXML:

Final Cut Pro ──Export XML──▶ Edit Twin edits the timeline ──Import XML──▶ new project in Final Cut Pro

• Frame-accurate. All maths uses exact rational time, the same way FCPXML stores it, so cuts never drift.

• Non-destructive. Effects, keyframes, colour, roles and metadata Edit Twin doesn't touch are carried through as they are. Connected clips (B-roll, titles, music) survive cuts underneath them.

• Checked. Every result is validated against Apple's FCPXML DTD (from inside Final Cut Pro) before import, and every edit can be undone.

• Local speech-to-text with Parakeet (parakeet-mlx, Apple Silicon) or Whisper (mlx-whisper / faster-whisper, prompted to transcribe verbatim), keeping the fillers and repeats you want to cut, with your saved names corrected afterwards.

• Style learning compares the kept source ranges of the two versions, uses the audio to tell pauses from words, and grid-searches pause settings to match your trims.

• Live control of the app (menus, shortcuts, playhead) uses AppleScript / System Events.

Limits (honest list)

• Beta. So far it's been used on one creator's Mac (Final Cut Pro 11.2, Apple Silicon) with single-camera talking-head footage. I will refine this as I go, so please report what breaks!

• Mac only, and the live app controls need the permissions above. If menu automation fails on your setup, export with File → Export XML… yourself and give Claude the file path.

• Edits apply to the primary storyline. Speed-changed (retimed) clips aren't cut inside. Multicam, compound and synced clips are skipped by pause and silence detection.

• A look is saved as the effects stack on an adjustment clip. Paid plugins (e.g. colour plugins) and LUT files must be installed on the Mac that uses it.

• render_preview is a rough preview (straight cuts, no effects or titles). The real result is in Final Cut Pro.

• Captions are regular titles (one per caption), so they're easy to tweak but a long video can have hundreds of them. A caption style described in words uses Final Cut's Basic Title; copy a title you styled yourself for animation or effects. A style copied from a title keeps that title's exact size and position, so check it when using it on a project with a different resolution.

• Speech-to-text word timings are approximate (Whisper occasionally stretches them over pauses; Parakeet's word ends are within 100 ms about half the time), so always check the plan before approving.

• Parakeet's punctuation and capitals are a little weaker than Whisper's; the captions skill checks them in the dry run. Names it mishears badly (not just a close spelling) need an exact fix once.

Files and disk space

Edit Twin never changes your Final Cut Pro library or media directly. It writes:

Settings you can pass as environment variables when registering:

For example, to keep everything on an external drive, run this from the cloned folder:

claude mcp remove edit-twin --scope user
claude mcp add --scope user -e EDIT_TWIN_DIR="/Volumes/MyDrive/Edit Twin" -e HF_HOME="/Volumes/MyDrive/.huggingface" edit-twin -- "$PWD/.venv/bin/edit-twin-mcp"

Privacy

• Transcription, pause detection, loudness and previews run on your Mac. Your video and audio files are never uploaded.

• To plan and make edits, Claude receives what the tools return: transcripts, timeline details (clip names, timings, effects and media file paths), and the screenshots or preview frames you ask for. That goes to Anthropic like the rest of your Claude Code conversation.

• Edit Twin itself sends nothing anywhere. The only network access is the one-time model download from Hugging Face.

Uninstall

claude mcp remove edit-twin --scope user
rm -rf ~/.claude/skills/edit-twin-rough-cut ~/.claude/skills/edit-twin-captions
rm -rf /path/to/edit-twin-mcp            # the cloned folder, including .venv
rm -rf ~/.cache/huggingface/hub/models--mlx-community--parakeet-tdt-0.6b-v3     # Apple Silicon models
rm -rf ~/.cache/huggingface/hub/models--mlx-community--whisper-large-v3-turbo

Delete ~/Movies/Edit Twin too if you don't want to keep your style and exports.

Development

python3 -m venv .venv && .venv/bin/pip install -e '.[transcribe,parakeet]' pytest
.venv/bin/pytest -q tests     # self-contained: generates its own footage, no Final Cut Pro needed

The same tests run on GitHub Actions for every pull request (.github/workflows/tests.yml), on macOS and Linux. Apple's DTD check only runs locally on a Mac with Final Cut Pro.

Support

Edit Twin is a free, as-is side project. Issues and pull requests are welcome, but I can't promise to fix every setup. If it saves you editing time, a ⭐ or a tag on socials (@loveaction) would be nice!

License

MIT