Skill: Cut

This skill builds a timeline from a library.

1. Confirm the library and pre-flight readiness

You need a library before any cut work. If one is already in context from the current conversation, use it. Otherwise show recent libraries (ruby lib/buttercut/library.rb recent 5) and let the user pick.

Once the library name is known, check if the library is ready (all footage processed).

ruby lib/buttercut/library.rb <name> ready

Exit code 0 means the library is ready for cut building (Library.ready? is the source of truth on what that means — don't re-derive the criteria here). If it exits non-zero, stop. Run ruby lib/buttercut/library.rb <name> summary to surface the incomplete clips and tell the user the library needs to finish processing (point them at the process-library skill). Don't try to cut around missing clips.

2. Determine Task Type

Ask the user with AskUserQuestion tool if available. Otherwise ask in text in this order.

Ask plainly. "Roughcut" in the user's opening request is trained vocabulary, not a confirmed choice — present the options and let them pick. Don't explain to the user why you're asking, and don't apologize for re-asking; the question stands on its own.

You're going to be tempted here to just move forward and assume the user really wants a story shaped roughcut, but they're just using this term loosely. You absolutely must tell them the next statement and question before moving forward:

If the library is processed, tell them that it's ready and the number of clips that are processed. Then ask them what kind of cut they want. Again, they probably said "roughcut", but we've just trained them on that word. You must ask.

Example framing: "Library is ready. All footage processed. What kind of cut do you want to build?"

Options:

1. Scene — One story beat, typically 30–90s.
2. Selects / Find clips — Flat reel of clips matching some criteria (best takes, mentions of a topic, B-roll on a theme).
3. Script Edit — Give ButterCut a written script and the agent will find the footage and edit to the script.
4. Custom task — Anything else you want.
5. Agent Roughcut — A full story-shaped cut. Plan with the agent and then let a sub agent make most of the decisions. (Experimental and can use a lot of tokens)

The roughcut path runs a deeper flow because the agent needs to explore the library broadly, read many summaries, generate fresh contact sheets, and shape a narrative across many clips. The other four paths the main thread handles directly with the user.

3. Build the Cut (produces YAML)

Both paths produce a YAML at libraries/[library-name]/cuts/[slug]_[YYYYMMDD_HHMMSS].yaml.

What a cut can express

A quick menu for shaping the cut with the user. Full field list and formats: skills/cut/cut_yaml_schema.md.

• Trimmed video — a clip cut to in/out points.
• Stills — an image held for a set duration (timeless and silent).
• Mute — silence a clip's own audio (e.g. you'll score it with music, or its source audio is unusable).
• Timeline format — override the output frame rate and resolution; by default they follow the first video clip.

Single-track: clips play in sequence and each carries its own audio.

Roughcut path

Read skills/cut/roughcut_path.md and follow it.

Scene / Selects / Custom / Script path

Read skills/cut/direct_path.md and follow it.

4. Verify the footage is reachable

The export reads every source file the cut references, so before exporting confirm the footage is actually live — a drive can be unplugged or renamed since the library was built:

ruby lib/buttercut/library.rb <name> verify_media

Every clip ok? Continue. If any come back missing or phantom, don't export — read skills/cut/missing_footage.md and follow it to reconnect the footage first.

Planning and building a cut don't need the drive plugged in — only the export does. So this check lives here, right before export, not at the start: the user can play with cuts on an unplugged drive and only reconnect when they're ready to hand a timeline to their editor.

5. Determine the Editing Application

Now that the cut YAML exists, resolve one editor value for the export:

1. If library.yaml has editor set, use it.
2. Otherwise fall back to libraries/settings.yaml's editor and write the value back to library.yaml.
3. If neither has one, ask the user (Final Cut Pro X / Adobe Premiere Pro / DaVinci Resolve), then save the choice to both library.yaml and libraries/settings.yaml.

6. Export the Cut

Run the export with the editor resolved in step 5 and the YAML produced in step 3:

# Final Cut Pro X
ruby lib/buttercut/export.rb --editor fcpx libraries/[library-name]/cuts/[slug]_[timestamp].yaml libraries/[library-name]/cuts/[slug]_[timestamp].fcpxml

# Premiere Pro
ruby lib/buttercut/export.rb --editor premiere libraries/[library-name]/cuts/[slug]_[timestamp].yaml libraries/[library-name]/cuts/[slug]_[timestamp].xml

# DaVinci Resolve
ruby lib/buttercut/export.rb --editor resolve libraries/[library-name]/cuts/[slug]_[timestamp].yaml libraries/[library-name]/cuts/[slug]_[timestamp]_resolve.fcpxml

DaVinci Resolve fallback (temporary). resolve above is the default and what every new cut should use. If the editor tells you a previous Resolve export failed to import, offer to re-export with --editor resolve_legacy instead — it writes the older FCP7 XML format Resolve exports used before FCPXML, as a compatibility fallback:

ruby lib/buttercut/export.rb --editor resolve_legacy libraries/[library-name]/cuts/[slug]_[timestamp].yaml libraries/[library-name]/cuts/[slug]_[timestamp]_resolve.xml

Don't offer this proactively or use it by default — only reach for it after the editor reports an import problem with the FCPXML export.

7. Copy File to Desktop (if enabled)

Check libraries/settings.yaml for save_to_desktop_after_export:

1. If the key is true, copy the exported XML to ~/Desktop/ so it's easy to grab and import into the editor.
2. If the key is false, skip this step.
3. If the key is missing, ask the user whether to drop a copy of every export on the Desktop, save their answer (true/false) to libraries/settings.yaml, then act on it.

cp [library xml path] ~/Desktop/

The library copy stays as the canonical artifact; the desktop copy is a convenience drop.

8. Backup Library

Run the backup-library skill. This snapshots the entire library directory so progress can be restored if needed.

9. Report Results

Surface the path to the XML — the library path, or the desktop path if that's enabled. For roughcuts, also include very abbreviated editorial notes from the sub-agent's return message; small fixes you can do directly in the YAML and re-export without another sub-agent. Do not include the YAML path — it's an internal build artifact, not something the user opens.

Include the one-line import instruction for the editor used:

• Final Cut Pro X: Open the cut in Final Cut Pro with File → Import → XML
• Adobe Premiere Pro: Open the cut in Premiere with File → Import, then select the XML file
• DaVinci Resolve: Open the cut in Resolve with File → Import → Timeline, then select the exported .fcpxml file (.xml if you used the resolve_legacy fallback)

10. Open in Editor (if enabled)

Check libraries/settings.yaml for open_in_editor_after_export:

1. If the key is true, open the exported file directly in the user's editor.
2. If the key is false, skip this step.
3. If the key is missing, ask the user whether exports should be opened automatically, save their answer (true/false) to libraries/settings.yaml, then act on it.

Use open -a with the correct application name so macOS doesn't fall back to a text editor or Xcode:

# Final Cut Pro X
open -a "Final Cut Pro" [xml path]

# Adobe Premiere Pro
open -a "Adobe Premiere Pro" [xml path]

# DaVinci Resolve
open -a "DaVinci Resolve" [xml path]

If this is enabled, tell them "I've opened the file for you in application_name. Let me know if I can help with anything else."

Use the desktop copy path if step 7 placed one there; otherwise use the library path.

Guidelines

** Important ** Talk to the user like a video editor, not a programmer. Hide technical details. Don't mention YAML at all. Don't use em or en dashes.

Bad: "Got it — 3-second podium clips only. I'll write the YAML now." Good: "Got it. Three second podium clips only. I'll start the edit." Bad: "I have a clear picture of all 48 clips. Let me build the YAML now" Good: "I have a clear picture of the event. Let me build the edit now."

Note: If users ask for you to do something that isn't natively supported by ButterCut for their video editor, read the misc-task skill for guidance.