FableCut docs

The manual for FableCut, built from CLAUDE.md in the repo: the same text your agent reads through the fablecut_docs tool, so what you read here is what it knows.

Studio (no install)The same editor at studio.fablecut.space, with nothing to install. It edits a folder on your own disk, and Claude Code, claude.ai, ChatGPT or any MCP client can drive it by link.MCP toolsConnect an agent, and the calls it uses to read and change your timeline without burning tokens.project.jsonThe whole edit in one file: canvas, markers, tracks, media and clips.Clip propsEvery property a clip can carry and its default. A key a clip leaves out falls back to these.CompositionsBuild a lower third, a logo sting or a whole scene once as a composition, then place it anywhere as one clip that moves, masks and grades like a picture, from the bin or by an agent with addComp, inComp and precompose.Media managementFile details, search, filters, sorting, tags and collections, where each file is used, relinking missing files, and proxies for heavy footage.ProjectsKeep many projects in one FableCut: a dashboard to open, create from a canvas or template, duplicate, rename, take notes on, tag, archive and delete them, and fablecut_projects for agents.VersionsSaved copies of a project you can compare and go back to, made by you, every few minutes, and before an agent edits; restoring is never destructive, and a backup carries them all.SequencesSeveral timelines in one project - a 16:9 and a 9:16 cut, cut-downs, alternatives - sharing its media and compositions, each with its own canvas, mix and delivery settings.Editing rulesHow tracks, links, locks, targeting and the trim tools behave, for people and agents alike.Asset librarySound effects, overlays, fonts and animated SVGs that ship with the editor, and how to make your own.Audio mixHow clips reach the speakers and the export: clip gain, channels, track faders, the master, and loudness normalize.TranscriptsTurn speech into words with times, in the browser, then read, search and cut the edit like text: in the Transcript tab, or from an agent with fablecut_transcribe.CaptionsCaptions timed word by word from the transcript, in four styles, burned into the picture; SRT and WebVTT out and in.ColorGrade a clip with wheels, exposure, white balance and tone, and check it with scopes: in the Color workspace, or from an agent with setGrade and fablecut_scopes.MasksCut what a clip shows with rectangles, ellipses, bezier and free-hand shapes: feathered, expanded, inverted, combined and keyframed, from the monitor or from an agent with setMask.Track mattes and blendingCut a clip with the picture on another track by its alpha or its brightness, and lay clips over each other with blend modes, from the Inspector or from an agent with setMatte.TrackingFollow a point or a region through a video clip, then make a mask follow it or pin a title, sticker or another clip to it, from the Inspector or from an agent with fablecut_track.Shapes and parentingMotion graphics: vector shape layers with fills, strokes, groups and trim paths, null objects, parenting and the anchor point, keyframed on the monitor or by an agent with setShape and setParent.Motion pathsBend a clip's travel into a curve, turn it along the way, blur fast moves with a shutter angle, and set titles along lines, arcs, circles and drawn paths, on the monitor or by an agent with setMotionPath and setTextPath.Presets & templatesPut a ready-made entrance, exit, emphasis or loop on any clip, and place lower thirds, logo animations and social layouts whose text, colours and logo you fill in, from the bin and the Inspector or by an agent with applyPreset and addTemplate.RecipesShort answers for common edits: grades, captions, speed ramps, transitions and more, each one a few props away.Remake a referenceTurn a video you like into a blueprint of shots, beats and energy, then rebuild it with your own footage.Look at the footageShow an agent what the footage holds: one frame, a contact sheet across a clip, or the composed timeline - as an image, or as text-only measurements for models without vision.REST APIThe HTTP endpoints behind the editor, for scripts and tools that don't speak MCP.ExportThe three export engines, which range gets exported, and the ffmpeg encoding profiles.

Run#

node server.js        # → http://localhost:7777   (from npm: npx -y fablecut)

Files: index.html + style.css + app.js (editor UI), server.js (API + hosting), project.json (the timeline - THE file to edit), media/ (project footage), library/ (default asset library, see below).

How Claude Code edits a video#

Ensure the server is running (background: node server.js, or fablecut_status).
Put source files in ./media/ (copy them in, import via the UI / + URL, or fablecut_import_media with a local path or HTTPS URL).
Read project.json, modify media / clips, increment revision, write it back.
The browser UI (if open) reloads instantly. The user previews/exports from the UI.

Rules:

Prefer fablecut_set_project over direct file writes - it detects conflicts automatically (see the MCP section above). If you do write project.json directly, read it immediately before writing (never write from a stale read: if the user tweaked something in the UI between your read and write, that write destroys their changes). The UI detects external changes by revision comparison, so a write that does not bump revision is invisible to it.
Make each edit a single atomic write (read → modify → write once), and bump revision (integer). Partial multi-step edits can be picked up half-finished.
New media entries may omit duration - the browser probes it and writes it back. If you need the duration yourself, re-read project.json after a second or two, or probe with ffprobe.
Don't edit project.json while the UI may be mid-drag - the UI defers external reloads during gestures, then picks up the next change.

Edit this in CLAUDE.md The whole manual as Markdown