Skill: Process Library (parent brief)

This skill is the main thread's playbook for the Analyze Video workflow step — processing the footage in a library that already exists. Use it whenever the user wants to:

• Analyze a newly created library (this is where create-library hands off after scaffolding).
• Return to an existing library and continue from wherever analysis left off.
• Add new footage to an existing library and analyze just the new clips.

It orchestrates the full transcribe-audio → contact sheets → summaries pipeline. The mechanics of each analysis step live in skills/analyze-video/SKILL.md; this skill calls into them.

Step 1 — Locate the library

You need an existing library to process. Confirm which one:

bash
ruby lib/buttercut/library.rb <name> exists   # exits 0 if it does, 1 if not

If it exists:

• Read the snapshot — one call gives you top-level metadata plus the clip-completion breakdown (video_count, incomplete_count, and the list of incomplete clips with their missing fields):

bash ruby lib/buttercut/library.rb <name> summary

• Run any schema migrations from AGENTS.md → Critical Principles before touching anything else.
• Continue from whatever step is incomplete.

If the directory exists but exists returns 1 (library.yaml missing):

• Check what files are present (transcripts/, cuts/, etc.) and inform the user of the current state.
• The library needs scaffolding — use create-library to restore consistency, then return here.

If no library directory exists:

• There's nothing to process. The user wants to start a new project — use the create-library skill first, which will hand back here once the library is scaffolded.

To find libraries by recency (for "the library I was just working on" / "resume a recent one" prompts):

bash
ruby lib/buttercut/library.rb recent [N]   # N most-recently-touched libraries (default 10)

Step 2 — Add new footage

If the user is adding new footage to an existing library, append the clips first. add_media takes videos and images together — the type is inferred from each file's extension:

bash
ruby lib/buttercut/library.rb <name> add_media /abs/new1.mov /abs/photo.jpg

Each new video entry starts with empty transcript, contact_sheet, and summary; each image entry starts with an empty summary only. Empty means "todo." The analysis steps below are idempotent and only touch clips missing an artifact, so they'll process just the new clips — and because the transcript/contact-sheet phases are video-only, images flow straight to the summary step.

If you're simply resuming or processing a freshly created library, skip this step.

Step 3 — Analyze footage

Inform the user: "Found N] videos (total size]). Starting footage analysis..."

Follow skills/analyze-video/SKILL.md end-to-end. That skill covers keeping the Mac awake during processing (caffeinate), footage processing (transcripts then contact sheets, two deterministic process_footage.rb runs), optional transcript refinement, summaries (Sonnet sub-agents, batched + rolling), and the post-analysis footage-understanding pass.

As footage gets processed, don't make assumptions about the the footage based on the filename or camera brand. A dji clip is not "drone footage" just because of the brand. DJI also makes gimbal and cinema cameras. Sony makes mirrorless cameras as well as action cameras. Don't characterize footage as aerial, drone, etc unless the footage reveals it.

bash
ruby lib/buttercut/library.rb <name> update_metadata footage_summary "subjects/locations/activities/visual style"

The full understanding pass at the end of analyze-video is where this gets refined.

Analyze ALL videos before offering to create rough cuts.

Step 4 — Verify readiness

Before reporting analysis complete, confirm the library passes the same gate the cut skill uses:

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

If it exits non-zero, run ruby lib/buttercut/library.rb <name> summary to list the incomplete clips, finish the missing artifacts (loop back into whichever analyze-video step owns them), and re-run ready until it passes. Don't claim analysis is done while Library.ready? is false.

Step 5 — Backup

After all analysis completes, automatically create a backup using the backup-library skill, scoped to just the library you processed: ruby lib/buttercut/backup_libraries.rb --library <library-name>. This writes a single archive under ~/Documents/buttercut-video-editor-backups/<library-name>/ (or wherever backups_dir in libraries/settings.yaml points). If backups_dir isn't set yet, the script silently uses the default — don't prompt during process-library.

Notes

• A single tmp/ directory inside the buttercut project root is used for all temporary files. Create subdirectories as needed and delete after use.
• Reprocessing footage: process_footage.rb only handles clips missing an artifact. To rebuild ones that already exist, re-run the relevant step (transcripts or contact-sheets) with --force (optionally --clips a.mov,b.mov). See analyze-video Step 2.
• Migrations: every time you read a library.yaml, check its schema against templates/library_template.yaml. If anything's missing or renamed, run ruby lib/buttercut/library.rb migrate to migrate all libraries at once. See AGENTS.md → Critical Principles for the migration trigger list.