figcraft/docs/mcp.md

FigCraft MCP server

FigCraft ships a Model Context Protocol server so AI agents can design with it: create and edit layers, run any menu command, inspect the result as JSON and look at it as a PNG. It speaks newline-delimited JSON-RPC 2.0 over stdio (MCP protocol 2025-06-18; 2025-03-26 and 2024-11-05 clients are accepted too).

The server lives in crates/mcp (figcraft-mcp) and is started by the CLI:

Command	Backend
figcraft-cli mcp	Headless: an in-process engine session with one untitled document. No window; renders with the CPU renderer.
figcraft-cli mcp --attach <port>	Attached: drives a running FigCraft app through its control channel (figcraft --control <port>). The user sees every change live.

--attach also takes host:port. The control channel only listens on 127.0.0.1.

Configure a client

Build the CLI first (cargo build --release -p figcraft-cli) and use the absolute path to target/release/figcraft-cli.

Claude Code

# headless
claude mcp add figcraft -- /path/to/figcraft-cli mcp
# drive the running app (start it with: figcraft --control 7979)
claude mcp add figcraft-app -- /path/to/figcraft-cli mcp --attach 7979

Or in a project's .mcp.json:

{
  "mcpServers": {
    "figcraft": { "command": "/path/to/figcraft-cli", "args": ["mcp"] }
  }
}

Claude Desktop

claude_desktop_config.json (Settings > Developer > Edit Config):

{
  "mcpServers": {
    "figcraft": { "command": "/path/to/figcraft-cli", "args": ["mcp"] },
    "figcraft-app": { "command": "/path/to/figcraft-cli", "args": ["mcp", "--attach", "7979"] }
  }
}

Conventions agents must know

• Coordinates are page units (1 unit = 1 px at 100% zoom), x right, y down.
• create_node and set_properties take x/y relative to the parent (the page when there is no parent, so they are page coordinates then). inspect_document reports parent-relative x/y plus absoluteBounds in page coordinates.
• Children of an auto-layout frame are positioned by the layout: set layout, gap, padding, mainAlign, crossAlign, sizingH/sizingV instead of x/y. More auto layout props:
  • sizingH / sizingV: fixed, hug (auto layout frames and text) or fill (children in an auto layout flow). A child can't fill an axis its parent hugs: setting fill turns the parent fixed on that axis, and a parent set to hug turns the children that filled it fixed. A layer moved out of auto layout (or whose frame loses it) keeps its size as fixed. Fill children share the space like CSS flexbox, within their min/max.
  • minWidth / maxWidth / minHeight / maxHeight (px, null removes) bound Hug, Fill and Fixed sizes; a hugging text wider than its max width wraps.
  • absolute: true takes a child out of the flow (it stays where it is and follows its constraints when the frame resizes; Fill becomes Fixed).
  • crossAlign: "baseline" lines up the first text baselines in horizontal layouts (other layers align to the top; nested auto layout frames use their first child's baseline).
  • wrap with crossGap (alias rowGap) for the gap between wrapped rows.
  • Grid (layout: "grid"): gridColumns, gridRows (minimum; rows grow), columnGap / rowGap, track sizes columnTracks / rowTracks as [120, "1fr", "auto"] (px fixed, fr fill share, auto hug) or the layout.setTrack {axis, index, sizing, value?} command; on a child, gridColumn / gridRow (0-based anchor cell, null = placed automatically) and gridColumnSpan / gridRowSpan. inspect reports a grid child's resolved gridCell.
• Every menu action is a command (list_commands), and most commands act on ids when given, else on the selection. New layers become the selection.
• Colours are "#RRGGBB" or "#RRGGBBAA". Inside fills, strokes and effects passed through the MCP tools, color may also be a hex string and gradients can be written {"type": "linearGradient", "stops": ["#7048E8", "#1098AD"]}; the server converts them to the engine's paint JSON.
• Colour profile: colour values are in the file's profile, sRGB (default) or Display P3 (inspect_document reports colorProfile). file.colorProfile {profile: srgb|displayP3, convert?} changes it: convert (default true) converts every colour value so colours keep their appearance; false keeps the values and reinterprets them. Images are treated as sRGB and managed into the file's space. PNG exports are tagged (sRGB chunk, or a Display P3 ICC profile plus cICP), Display P3 JPG and WebP embed the ICC profile, and SVG and PDF export Display P3 files converted to sRGB (out-of-gamut colours clip).
• Image adjustments: image paints carry filters (exposure, contrast, saturation, temperature, tint, highlights, shadows; each -1..1). image.adjust {ids?, target?: fill|stroke, index?, preset?, filters?} applies a built-in preset (vivid, muted, warm, cool, blackAndWhite, fade, reset) or one saved in the file, with any filters values on top. image.savePreset {name, filters?} saves the current (or given) adjustments in the file, image.deletePreset {name} removes one and image.presets lists both kinds.
• Text props (fontFamily, fontStyle, fontSize, lineHeight, letterSpacing, textDecoration, textCase, textFills, fontVariations…) apply to the whole layer, or to chars start..end when given (text.style {id, start, end, …} does the same). Styled ranges come back as styledRuns. Variable fonts: fontVariations (alias variationSettings) sets axis values in user units, e.g. {"wght": 550, "wdth": 85} (null = back to what the style name implies); text.setVariations {variations, replace?} merges instead. text.fonts {family, style?, axes: true} lists a font's axes and named instances (named instances are also valid fontStyle values). OpenType features: features {"liga": false, "tnum": true}.
• Text styles link chars, not just layers: style.apply {style, ids?, start?, end?} with a text style links chars start..end (while text is edited, the selected chars; else whole layers), and style.detach {which: "text", start?, end?} unlinks them (values stay). A layer's styles.text is the style all its chars share (none when they differ); get_node lists the linked chars as textStyleRanges ([start, end, style id]). Changing what a text style sets (font, size, line height, letter spacing, decoration, case, axis values) on linked chars unlinks them; style.update moves every linked char. style.create {type: "text", name} takes the selected chars while editing; a value may use the node.set spellings ({"fontSize": 32, "lineHeight": "120%", "letterSpacing": "2%"}).
• Live previews: text.preview {command, params} shows what style.apply, library.applyStyle, text.setVariations or text.style would do on the canvas without an undo step (in place of an earlier preview); text.endPreview puts the document back. Any other command ends the preview first, so running the command for real commits it as one undo step.
• Every mutation is one undo step (batch makes several one step). A failing command leaves the document as it was.
• Programmatic calls never open dialogs.
• Verify your work: inspect_document / get_node for numbers, screenshot for pixels.

Tools

Tool	What it does
list_commands {filter?}	Every command: id, label, menu, shortcut, undoable, params doc.
run_command {command, params}	Run any command (e.g. align.left, layout.add, component.create, instance.place (drop an instance at a page point into the frame or auto layout slot under it), component.exposeInstance / instance.exposed (nested instance properties on instances), component.makeSlot / instance.slotInsert / instance.resetSlot (slots, below), inspect.code (CSS, HTML + CSS for a whole frame, React, SwiftUI or Jetpack Compose for a layer; components take their properties as parameters and instances are calls, see Dev Mode below), inspect.properties (layout, auto layout, typography, fills, strokes and effects with their style and variable names), inspect.assets (layers under the selection with export settings), style.create, variable.bind, variable.update (rename, describe, scope), variable.set with {alias}, variable.renameMode / variable.removeMode, variable.deleteCollection, proto.interaction.add).
batch {commands: [{command, params}], label?}	Several commands as one undo step (command.batch); all-or-nothing.
create_node {type, x, y, width, height, parent, index, name, text, path, props}	Create a frame, rectangle, ellipse, polygon, star, line, arrow, text, vector, section, component or slice; returns {id, node}.
set_properties {ids, props}	node.set on layers (geometry, fills, strokes, effects, corner radius, auto layout, sizing, constraints, masks (isMask, maskType: alpha|vector|luminance), handoff status (devStatus: none|readyForDev|completed; marking again clears "Changed"), a section's sectionContentsHidden, text…); returns the updated layers.
inspect_document {depth, allPages}	The document as JSON (layer tree, styles, selection, history).
get_node {id, depth}	One layer as JSON.
select {ids}	Replace the selection ([] deselects).
export {ids, format, scale | size, path?, bleed?, cropMarks?, bleedMarks?, cmyk?}	png, jpg, svg, webp, pdf; size is 2x, 512w or 512h. PDF: frames one page each (sized in points), anything else together on one page; print options: bleed (points or a length like "3mm", "0.125in"), crop and bleed marks, CMYK colour (see Exports below), also taken by file.export, file.exportLayers, file.exportFramesPdf and stored per export setting by export.add / export.update; run_command file.exportFramesPdf {page?, path?} writes every top-level frame of a page. Without path, images come back as MCP image content, SVG as text. Layers' own export settings: run_command with export.add / export.update {index, size?, suffix?, format?} / export.remove and file.exportLayers {ids?, dir?} (every layer once per setting, named <layer><suffix>.<format>).
screenshot {ids?, scale?, maxSize?, window?}	PNG of the page (with background) or of layers, scaled to fit maxSize (default 1600). window: true captures the app window when attached.
open_file {path, variables?} / save_file {path?}	Open .figcraft, .json (FigCraft JSON or REST API file JSON with its variables, see below), .svg (see Importing SVG below) or an image; save as .figcraft.
undo / redo	Step through history.
pointer {kind, x, y, to?, steps?, tool?, shift, alt, cmd}	Mouse gestures in page coordinates with the current tool: click, double, drag, down, move, up, hover.
key {key, shift, alt, cmd}	A shortcut or key as if typed on the canvas (every default shortcut, tool keys, Escape, Delete, arrows, number keys for opacity; while editing text, the text shortcuts and then text editing keys). Keys are names like A, 0, Enter, ArrowLeft, =, /, or egui's (Plus, Questionmark); cmd is Cmd on macOS and Ctrl elsewhere.
type_text {text, id?}	Type into the text being edited, or replace the contents of text layer id.
inspect_ui {}	Tool, view and status (and panels/timings when attached).

Sections, handoff and arrow keys

run_command with object.wrapInSection {ids?, name?} (Wrap in new section: layers on the page or in a section, with some room around them), section.toggleContents {ids?, hidden?} (a section hiding its contents shows only its name and outline; its layers aren't drawn or hit, and the layers panel dims them), object.resizeToFit. A frame or section marked devStatus: readyForDev turns "Changed" (devChanged: true in get_node) when a layer in it is edited, added or removed; dev.resolveChange {ids?, reason?} returns it to Ready for dev and keeps the reason (devNote). Frames in sections are top-level frames (flows can start there; proto.flow.add); a "Navigate to" whose destination is a section shows the frame of it shown last in the presentation, else its first.

transform.nudge {dx, dy} (arrow keys) moves auto layout children one place instead of nudging: along the flow, to the previous/next row of a wrapping layout, to the neighbouring grid cell, and, at the end of a flow or across a row's axis, into the neighbouring nested auto layout frame when the frame around flows that way (a list of rows: Down moves an item into the row below).

Keyboard shortcuts

The default shortcuts live in one table (figcraft_engine::keymap), grouped like the public shortcut reference (Essential, Tools, View, Zoom, Text, Shape, Selection, Edit, Transform, Arrange, Components, Prototype) with the macOS keys and, where they differ, the Windows/Linux keys (for example Use as mask is ⌃⌘M on macOS and Ctrl+Alt+M elsewhere; Bring to front ⌥⌘] and Ctrl+Shift+]). list_commands reports each command's first key for the platform the server runs on; key resolves keys the way the canvas does. Commands behind keys:

• object.opacityKeys {digits, ids?}: the opacity number keys. One digit is tens of percent ("0" is 100%); two digits are the exact percentage ("45" is 45%, "05" is 5%), what typing two digits in quick succession does on the canvas.
• view.zoomAt {x, y, out?, width?, height?}: the zoom tool (hold Z on the canvas; Alt zooms out). A point zooms one step in (or out) keeping that page point in place; an area fills the view.
• view.designPrototype (Shift+E), view.devMode (Shift+D) and view.leftSidebar (Shift+Cmd+\) switch the right panel's tab or hide the left sidebar in the app (no-ops headless).
• doc.nextTab / doc.previousTab (Ctrl+Tab / Ctrl+Shift+Tab): the next or previous open file.
• view.nextRegion / view.previousRegion (F6 / Shift+F6, live while editing text too): move the keyboard between the app's regions (toolbar, layers, canvas, properties). In the app, Tab and Shift+Tab then move between the region's controls, Enter or Space activate one, the arrows move along the toolbar and through the layer rows, and Escape returns to the canvas (no-ops headless).
• pref.reduceMotion {on?}: reduced motion (the interface's own animations off; the system's accessibility setting turns it on too). Prototype transitions still play.

Editing vectors

Vector edit mode is driven with run_command (or pointer/key for gestures): vector.edit.begin {id} (converts shapes to vectors), vector.edit.state (page-space overlay, the local network, each point's handle mirroring and the width points), vector.edit.tool {tool: move|pen|bend|paint|lasso|cut|eraser|width}, vector.edit.select {vertices?, segments?, add?}, vector.edit.selectAll, vector.edit.moveVertices, vector.edit.nudge, vector.edit.position {x?, y?}, vector.edit.setHandle, vector.edit.mirroring {mode: none|angle|angleAndLength}, vector.edit.smooth {smooth?}, vector.edit.bend, vector.edit.addVertex, vector.edit.connect {a, b}, vector.edit.pen {x, y, dx?, dy?} (continues from the pen's open end; clicking a point connects or branches), vector.edit.penEnd, vector.edit.paint {x, y} (paint bucket: fills or unfills the closed area under a page point), vector.edit.cut {segment, t} | {vertex}, vector.edit.erase {points, radius?} (the eraser), vector.edit.lasso {points}, vector.edit.delete, vector.deleteHeal, vector.join / vector.smoothJoin (join the selected points while editing), vector.edit.cornerRadius, vector.edit.end. Point indices refer to network.vertices in vector.edit.state; local coordinates are the layer's own.

The selected points' transform box: vector.edit.bounds ({x, y, width, height, corners, points}: the box in the vector's axes, x/y in the parent's coordinates like the Position fields), vector.edit.resize {width?, height?, center?} (keeps the top-left unless center), vector.edit.rotate {angle, cx?, cy?} (degrees counter-clockwise about the box centre or a page pivot), vector.edit.transform {matrix: [a, b, c, d, e, f], vertices?} (any page-space affine). While points are selected, object.flipH / object.flipV and the 90°/180° rotations act on them. On the canvas (pointer), dragging points, handles and pen clicks snap to other points and segment midpoints (this vector's and other vectors'), the usual layer targets and the pixel grid; cmd held while dragging turns the object snapping off.

Variable width strokes: stroke.widthProfile {ids?, preset?: uniform|wedge|taper|eye|rounded|pinch, points?: [[t, scale], ...]} (also node.set {widthProfile}; t runs 0–1 along each subpath by length, scale multiplies the stroke weight, widths in between are interpolated smoothly; no preset or points = uniform). While editing, the Variable width tool (width, ⇧W) drags width points: vector.edit.widthPoint {t, width? (px) | scale?} adds one, {index, t?, width? | scale?} moves or resizes it, {action: "remove", index} deletes it. Rendering, PNG/SVG/PDF export and vector.outlineStroke follow the profile.

Prototypes

Interactions are proto.interaction.add / set / remove / clear (a navigate action can keep the scroll position with preserveScroll: true). Variable actions: {type: "setVariable", variable, value} sets a value, or with expr an expression computed when it runs; {type: "setVariableMode", collection, mode} switches a collection's mode for the prototype (ids or names; modes chosen on layers inside the screen still win); {type: "conditional", blocks: [{condition?, actions}]} runs the first block whose condition holds (a block without one is the "else"). Expressions are {value: {type: number|string|boolean|color|alias, value}} (alias reads a variable) or {op: {op, args}} with add (text joins when a string is involved), subtract, multiply, divide, equals, notEqual, less, lessOrEqual, greater, greaterOrEqual, and, or, not and negate; {inMode: {variable, mode}} reads a variable's value in one mode of its collection whichever mode is chosen, and {mode: {collection}} gives the name of the mode a collection is in where the interaction runs (as text; it follows set variable mode actions). Variables, collections and modes may be given by name; they are stored by id. Expressions can also be written as text: expression: "count + 1" on a set variable action, or expression: "count >= 3 and not done" on a conditional block, in place of expr / condition (variables by name, {name} for any name; numbers, "text", true / false, #RRGGBB; or / ||, and / &&, not / !, == (or =), !=, <, <=, >, >=, + (joins text), -, *, / and brackets; accent[Dark] for a variable's value in a mode, mode(Theme) == "Dark" for a collection's current mode, names with brackets or spaces at their ends in quotes). Text expressions are checked: a condition must give true or false and a set variable's expression a value the variable can hold, otherwise the command fails with what's wrong (Something is missing at the end, No variable \x`, Can't compare a number with text). Single actions, also inside conditionals, are edited with proto.action.add {id?, index, path?, action}(→{path}), proto.action.set {index, path, action}, proto.action.remove {index, path}andproto.action.move {index, path, to}, where indexis the interaction andpaththe action:[i]the interaction's actioni, [i, b, j]actionjof blockbof the conditional actioni, and so on (for add, where it goes: [i, b, n]appends to a block withnactions; default: after the last action). A conditional's blocks:proto.conditional.addBlock {index, path, else?, expression? | condition?}adds an else if (before the else; by default the first boolean variable equal to its value) or withelse: truethe else,proto.conditional.setCondition {index, path, block, expression | condition}andproto.conditional.removeBlock {index, path, block}(removing the if when only an else is left removes the whole conditional). Every one is an undo step and applies to allidsgiven (layers with the same interactions). Flowsproto.flow.add/rename/remove, and the device, its rotation and the background proto.settings {device?, background?, rotation?, color?, width?, height?, responsive?} (None, iPhone 16, iPhone 16 Pro Max, Android Compact, iPad mini, MacBook Air, DesktoporCustom size; rotation portraitorlandscape, which turns phones and tablets; colorone of the device's colours by name, e.g.Black, White, Pink, Teal, Bluefor the iPhone 16 (an error lists them),""for the default;width/heightset the custom size's screen, 1–10000 points, and pickCustom size, which is a bare screen without a body). On a device the presented frame is sized to the device's screen: what doesn't fit is clipped, or scrolls when the frame's overflowallows it, whilefixedlayers stay on screen (pinned to the edges their constraints name). Withresponsive: true(saved in the file) the presented frame is instead resized to the device's screen, or without a device to the presenter's window at 100%, and its constraints and auto layout respond as when it is resized in the editor (an axis it hugs keeps hugging its content); the file's frames don't change.proto.present {start?}plays the prototype full-window andproto.preview {start?}in a resizable pane over the canvas that follows edits live;proto.closePreviewcloses it.proto.presentOptions {scale?, deviceFrame?, hotspotHints?, inspect?} sets how the full-window presenter sizes the prototype (fitscales it down to fit,fitWidthfills the width,fillcovers the window,actualshows it at 100%; what overflows pans), whether it draws the device, whether a click where nothing reacts briefly flashes the screen's hotspots (the layers with interactions, on by default; also in the presenter's Options menu) and whether its Inspect panel shows the size, colours and typography of the layer under the pointer (also the Inspect button in its bar); the options are kept for later presentations (in the presenter Z cycles them and R restarts). The player's state is ininspect_ui (presenter, preview: screen, scroll, scale, zoom, pan, the screen's hotspotsand whether they are flashing, theinspectedlayer) when attached, andui.set {presentScroll: [x, y]}scrolls its screen (see [control-protocol.md](control-protocol.md)). The presenter's Options menu offers Responsive next to the size options (without a device) or Responsive / Fixed size (on one), the sameproto.settings {responsive}`; its flow picker lists each flow with its description.

Local libraries

A .figcraft file can be published as a library and used from other files (local files only: no accounts, nothing on the network; the browser build has no file system, so there the commands that read library files return an error).

• Publish (in the library file): library.publish {description?, include?, exclude?} publishes the file's components, component sets, styles and variable collections as a new version (by default everything except names starting with . or _, or what the last publish offered; include/exclude take component ids and style or collection ids or names). A collection comes with its variables (values per mode, aliases, scopes), except those hidden from publishing (variable.update {variable, hiddenFromPublishing: true}). Components, styles and variables that published assets use (a component's bound variables, a variable's alias targets) come along, unoffered. Each asset keeps the version it last changed in; publishing with no changes is refused. Save the file (file.save) so other files see the new version.
• Enable: library.add {path} / library.remove {id} (id, name or path) / library.list {assets?} (versions, pending updates, errors; with assets: true each library's components, styles, variable collections (with their modes) and variables, and what this file can publish). Libraries are read read-only with size limits, and read again when the file changes.
• Use: library.place {library, component, x?, y?} (a component, set or variant by id or name; page point, default the view's centre) copies the component, with the components and styles it uses, into the file as a read-only main component and places an instance; library.import {library, component} only copies it (then instance.create, instance.swap…); library.swapAt {library, component, x, y} copies it and swaps the instance at that page point to it (as instance.swapAt, below). library.applyStyle {library, style, ids?, target?} copies a style in (linked, read-only) and applies it. Instances of library components behave like any instance: overrides, properties, variants, swap, reset, detach. Library components keep their variable bindings and explicit modes (bound to copies of the library's variables).
• Library variables: library.bindVariable {library, variable, field, ids?} copies a published variable in (linked, read-only, with the variables it aliases and its collection) and binds it like variable.bind; library.aliasVariable {library, alias, variable, mode?} makes a local variable's value an alias of a library variable; library.setVariableMode {library, collection, mode, ids?} sets a library collection's mode on frames (the page when no ids are given; the Design panel's Variable modes section lists enabled libraries' collections under the library's name and sets them this way); library.importVariable {library, variable} only copies it (then variable.bind, variable.set {value: {alias}}). The copies render without the library file. Editing the copies (library components, styles, variables or collections) is refused; edit the library file and publish.
• Update: library.updates lists the components, styles, variable collections and variables with a newer published version; library.acceptUpdates {ids? (library ids)} pulls them in, keeping instance overrides; bound layers, aliases and explicit modes follow the updated values.
• Paste between files: instances copied from another open file (edit.copy there, edit.paste here) follow their mains: library components join (or bring along) this file's copies of the same library, components the other file publishes as a library are used from it (and that library is enabled when the other file is saved), and other mains stay behind: the instance shows a missing main (component.restoreMain makes it a main here).

Swapping instances

• instance.swap {ids?, component} shows another component in the instances (overrides on layers with matching names stay; property values with the same names too). Nested instances can be swapped on their own (an override of the instance they're in).
• instance.swapAt {component, x, y} swaps the instance at a page point: of the instances under it (innermost first), the first showing a variant of the same component set, else the innermost (never one inside the dropped component). The Assets panel does this when a component is dropped onto an instance with Alt (Option) held, highlighting that instance while dragging.
• Instance swap properties offer preferred values: component.addProperty {type: "instanceSwap", default, preferred? [component or set ids]} and component.editProperty {name, preferred}; component.properties lists them, and the Design panel's swap menus show them first.

Slots

A slot is a frame inside a main component whose instances take any content of their own (add, remove and reorder layers there, unlike the rest of an instance). It is a component property of type slot (component.properties lists it: on a main with its layers, on an instance with value: {layer, edited, layers}).

• Define (on the main): component.makeSlot {id (a frame inside a main component), name?, preferred? [component or set ids]} (the property is named after the frame by default); component.editProperty {name, preferred}; component.removeSlot {id} (instances lose their own content in it). component.addProperty {type: "slot", layer} and component.bindProperty {field: "slot"} work too (one frame per component for a slot).
• Fill (on an instance): instance.slotInsert {id (the slot layer, or the instance with slot (property name)), component, index?, replace?} places an instance of a component in it; any structure command (shape.*, node.reparent, edit.paste with the slot selected, edit.delete, node.reorder, instance.place or a drag onto it) works inside it. The main's default content shows (and follows the main) until the slot is first edited; then the slot's layers are the instance's own (override group slot): kept across main updates, variant switches, copy/paste and detach, and instances placed there stand alone (their own overrides, properties and detach).
• Reset: instance.resetSlot {id} (or component.resetOverride {id, group: "slot"}, or component.resetInstance) brings back the main's default content.

get_node shows "slot": "<property>" on slot layers.

Shape builder

The selected shapes' outlines split the canvas into regions (areas covered by the same shapes). shapeBuilder.regions {ids?} lists them: an SVG path in page coordinates, the sources covering each one (top-most first), bounds and a point inside. shapeBuilder.merge {ids?, regions?, points?} makes one vector from the regions (by index, or the regions under page points), styled like the top-most shape over the first one; shapeBuilder.remove {ids?, regions?, points?} deletes them. Either way every shape covering a picked region loses that area (it becomes a vector, or goes when nothing is left), and each call is one undo step. The tool is tool.shapeBuilder (Shift+M): click or drag across regions with pointer to merge, add alt to remove; shapeBuilder.mode {mode: merge|remove} swaps what a plain click does.

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"shapeBuilder.regions","params":{"ids":[2,3]}}}}
{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"shapeBuilder.merge","params":{"ids":[2,3],"points":[[120,80],[160,80]]}}}}

Importing SVG

open_file {path} opens an SVG as a new document; run_command {command: "file.import", params: {path | data + name, x?, y?, center?}} adds it to the current page as a frame (top-left at x, y, or centred there with center: true, as pasting does). It comes in editable: groups named from their id, transforms baked into the layers, <rect>/<circle>/<ellipse>/<line> (and paths tracing those outlines) as rectangles with their corner radius, ellipses and lines, everything else as vectors; strokes with their width, dashes, caps, joins and miter limit; linear and radial gradients with their exact handles (gradientTransform, reflect/repeat unrolled, a focal point as the centre); patterns as image fills (fill, fit, crop or tile); clip paths as vector masks and masks as luminance or alpha masks; shadow and blur filters (feDropShadow, the offset / blur / flood / composite chains, colour-matrix shadows, inner shadows, feMorphology spread) as drop shadows, inner shadows and layer blurs; opacity and mix-blend-mode; text as text layers (fonts the SVG names when installed, anchors, letter spacing, styled <tspan> runs, stacked lines as one layer); images as image fills, and SVG images imported in place. CSS, <use>/<symbol>, units and viewBox/preserveAspectRatio are resolved. The result's warnings list what was left out (filters that aren't shadows or blurs, rotated repeating patterns, a clip path's own clip path). Linked files are never read, only data URIs; documents nested more than 512 elements deep are refused.

Importing REST API file JSON

The JSON returned by the public REST API's file endpoint (GET /v1/files/:key, best with geometry=paths so vectors carry their outlines) and its nodes endpoint opens like any document: open_file {path} (a new, untitled document; the JSON is never saved over) or run_command {command: "file.import", params: {path}} (pages appended to the current document, with their flows, prototype settings and variables). The result's warnings list what was skipped or approximated (unsupported layer, paint and effect types, video and gamepad triggers, expression functions other than a variable mode lookup over a variable and one of its modes, bindings to library variables, instances of components outside the file, which come in as frames). Pages, the layer tree, geometry, paints, strokes, effects, corners, constraints, auto layout, layout grids, exports, text with styled runs, vectors, components, component sets, instances and component properties are mapped, and so is prototyping: interactions (on click, hover, press, drag, after delay, mouse enter/leave/down/up and key triggers; navigate, overlays, back, scroll to, change to, open link, set variable (values, variable references and expressions), set variable mode and conditional (if / else if / else over expressions) actions; dissolve, smart animate, move, push and slide transitions with their easing, custom bezier and spring curves included), flow starting points, scroll overflow and fixed/sticky layers, and the prototype device. Image fills keep their imageRef and show a grey placeholder unless the image files sit in an images folder next to the JSON, named by imageRef (images/<imageRef>.png); nothing is fetched from the network.

Variables come from the local variables response (GET /v1/files/:key/variables/local): collections with their modes (the default mode first), values per mode, aliases and scopes. Pass it as variables (a path, or the JSON object or text) to open_file, file.open or file.import, put it next to the file as <name>.variables.json or variables.json, or embed its meta in the file JSON. Layers' boundVariables (sizes, gaps and padding, corner radii, opacity, stroke weight, visibility, text, font properties, single solid fills and strokes) and explicitVariableModes then link to them, so switching a mode with variable.setMode restyles the layers (mode: null sets a frame back to Auto, inheriting its parent's mode).

Comments

Comment threads live in the file, pinned to a page point or to a layer (anchor: a node id, or true for the innermost frame under the point) so they move with it; when the layer is deleted the pin stays where it was, on the nearest surviving parent. Driven with run_command: comment.add {x, y, text, page?, anchor?} (returns {id, link}), comment.reply {id, text}, comment.edit {id, text, reply?} and comment.delete {id, reply?} (a message is the thread's first one, or reply: an index into its replies; deleting the first message deletes the thread), comment.react {id, emoji, reply?, on?} (toggles your reaction), comment.resolve {id, resolved?}, comment.move {id, x, y, anchor?} (pins it to the frame under the new point unless anchor: false). Everyone acts as the name from Preferences (pref.userName {name}, default "You") unless author says otherwise; only a message's author can edit or delete it. @Name in a message mentions someone (comment.people lists the names used in the file).

Read state is kept per name: a new message is unread for everyone but its author; comment.markRead {id? | link?, read?} marks one thread (or, without id, all of them) read or unread (not an undo step). comment.list {page? | "all", filter? (all|open|resolved|mine|unread), sort? (date|page), query?, frame?} returns the threads with their position, frame/frameName, pageName, unread, link and replies (with edited times and reactions). Links are figcraft://comment/<id>: comment.link {id} returns one, comment.open {id | link, view?} goes to its page, zooms to its frame (fit, the default; center keeps the zoom; keep doesn't move) and opens it in the app, and comment.next {id?, dir?, …list params} steps to the next or previous thread of a list the same way. comment.zoom {ids} zooms in on a group of pins.

Version history

Named snapshots of the document, kept in the .figcraft file (they persist once the file is saved; a new, renamed or deleted version marks the file as changed). Driven with run_command: file.saveVersion {name?, description?} (returns {id, index, name, description, time}; untitled versions are named "Version N"), version.list (oldest first; time is Unix seconds), version.restore {id | index} (replaces the document with the version as one undo step; the file name stays), version.rename {id | index, name, description?}, version.delete {id | index} and version.duplicate {id | index} (opens the version as a new document tab). version.preview {id | index} shows a version in place of the document, read-only: edits, undo and gestures are refused until version.restore keeps it or version.exitPreview goes back. Saving, closing or saving a version ends the preview first, and version.list marks the shown version previewing. Indexes are validated (a negative or out-of-range index is an error). A file keeps at most 100 versions. version.autosave saves an automatic checkpoint (auto: true, named "Autosave") when the document has unsaved changes since its last version; the app runs it every 30 minutes for each open document, and a file keeps the newest 20 autosaves (user versions are never dropped for them). file.versionHistory returns the same list and opens the panel in the app.

Collaboration changes

collab.diff {against? (undo: the last undoable action, the default | saved: since the last save)} returns {changes, count, bytes}: the change batch a live session would send for that edit (per-property create / set / delete and document-level changes, see docs/collab-protocol.md) and its binary size. It changes nothing. In a live session, where undo is per user (edit.undo / edit.redo take back only your own steps, see docs/collab-protocol.md), only saved applies.

Live sessions

People (and agents) edit one file together and see each other's cursors, selections and viewports. Both the headless session and the attached app can host and join; each call takes in what happened since the last one and sends your edits (a joined file opens as a new document).

• collab.host {port?, bind?} starts hosting the active document: bind is "local" (this machine, the default), "lan" (the local network) or an interface address; the port is 47900, or any free one when it's taken (port picks one, 0 any). Returns the session as collab.peers does, with link (figcraft://join?host=…&file=…&token=…) and url (ws://…/?file=…&token=…): both carry the session's secret, so share them only with people you invite. collab.stop {} ends it.
• collab.join {link} (either form) returns at once with status: "connecting"; poll collab.peers until status is "live", or "failed" with a reason (a wrong token, a full session, an unreachable host). collab.leave {} leaves.
• collab.peers {} → {available, status (off|connecting|live|reconnecting|failed), reason?, attempt?, role (host|guest), me, name, color, fileName, pages, link, url, address, network, follow, syncing (the document arrived), document (the index of the synced open document), peers: [{id, name, color, presence: {cursor: [page, x, y], selection: [ids], viewport: [page, x, y, w, h], editing_text: {node, caret, selection?}}}]}.
• collab.cursor {x, y} puts your cursor at a page position (omit both to hide it): an agent's pointer. Your selection, page and view go out by themselves when they change.
• collab.follow {client} follows that person's viewport; collab.follow {} stops (so does any pan or zoom of your own, or Escape).
• On the session's document every command (or batch, or gesture) is one step of your own undo history: edit.undo / edit.redo take back only your steps and leave what others changed since. An edit the host refuses (someone deleted the layer) is rolled back and the reason is the session's message. While the connection is reconnecting, editing goes on; the edits go out when it is back (the same client, catching up with what it missed).

Plugins

Sandboxed WebAssembly plugins act through the same commands (see plugins.md for the manifest, the ABI and the Rust SDK). Driven with run_command: plugin.import {path} (a figcraft-plugin.json or its folder) or plugin.import {manifest, wasm} (the manifest as an object or JSON text and the module as base64, for this session only), plugin.list, plugin.remove {id}, and plugin.run {id, command?, params?, fuel?}, which returns {plugin, command, output, logs, calls, fuel}. A run is one undo step and is rolled back when it fails; a plugin only reads the document unless its manifest asks for write, may be limited to some commands, and can never touch files, other documents, the undo history, dialogs or other plugins. A headless MCP session starts with no plugins: import them first. plugins.runLast runs the last plugin command again.

Dev Mode

• Component code: inspect.code {id, language: react|swiftui|compose} on a component, a component set or a variant writes the component as a reusable unit: React (TSX) with a props interface, SwiftUI with a View struct, Compose with a @Composable function. Its component properties are the parameters, with their defaults: variant properties become string unions (React) or enums, booleans become flags around the layers they show, text properties strings, instance swaps views (React.ReactNode, AnyView, a composable lambda) and slots optional content. Every variant of a set shares one definition; in React the other variants' differences become CSS rules on data-* attributes. On an instance (or a layer tree containing instances) each instance is a call passing only the values it changes, e.g. <Button state="Hover" label="Buy" />, Button(state: .hover, label: "Buy"), Button(state = ButtonState.Hover, label = "Buy"). Names are escaped and unique (keywords get a suffix, default → defaultValue; names that would shadow framework types get one too, Text → TextComponent). inspect.componentCode {id?, language?} returns the parts: {component, name, set, properties: [{name, param, type, default, value? (instances)}], definition, usage? (instances)}.
• Annotations: notes for developers on any layer, each with optional pinned properties that Dev Mode shows with their current values (and the style or variable behind them). annotation.add {id?, label?, properties?} (a note, pinned properties or both; returns {id, index}), annotation.edit {id?, index, label?, properties?} (properties replaces the list), annotation.remove {id?, index?} (no index: all of the layer's), all undoable, and annotation.list {ids? | id? | page? ("all")} → {annotations: [{id, name, index, label, properties: [{property, label, value, token?, color?}]}]} (value is null when the layer doesn't have that property). Pinnable ids: width, height, top, left, rotation, opacity, cornerRadius, direction, gap, padding, alignment, fontFamily, fontStyle, fontSize, lineHeight, letterSpacing, textAlign, fill, stroke, strokeWeight, effects. A layer holds at most 64 annotations; notes are capped at 5,000 characters. They are saved with the file (get_node lists them as annotations); instances don't inherit their main's annotations and keep their own across main edits. In the app the Inspect tab draws them as callouts beside their layers and edits them in its Annotations section.
• Annotation categories: every annotation can have a category, drawn as the colour of its callout: the defaults are Development, Interaction, Accessibility and Content, and a file can add its own. annotation.add / annotation.edit take category (an id or name; null clears it) and annotation.list returns category: {id, name, color} and filters with {category: id | name | "none"}. annotation.categories {} → {categories: [{id, name, color, count}]}; undoable annotation.addCategory {name, color?} → {id} (a new one takes the first unused colour), annotation.editCategory {id, name?, color?} (rename, recolour; ids stay) and annotation.removeCategory {id} (its annotations stay, uncategorised). Names are unique (ignoring case), up to 64 characters; at most 64 categories. Files keep the list only once it differs from the defaults (old files open with the defaults). In the app, with nothing selected, the Inspect tab filters the callouts by category and edits the categories (colour, name, delete, add); each note has a category menu.
• Ready for dev: frames at the top of a page or section, and sections, carry a handoff status (node.set {devStatus: none|readyForDev|completed}). inspect.readyForDev {status?: readyForDev|completed|any, page?} lists them across pages (or on one page) in page and layer order: {items: [{id, name, page, status}]}. The Inspect tab sets the status of the selected frames and, with nothing selected, lists them with a status filter (click one to go to it, or its focus button to open it in the focus view).
• Compare changes: when a layer marked Ready for dev first changes (it turns "Changed"), the file keeps a copy of it and everything in it as it was just before that edit (saved in the .figcraft file only while there is a change; resolving the change, marking it again, another status or deleting it drops the copy, so the next change compares with that state). dev.compare {id?, show?} → {id, name, changed, snapshot, added, removed, modified, truncated, changes: [{id, name, type, change: added|removed|changed, depth, layers, properties?: [{section, property, before, after, text}]}]}: layers matched by id, added and removed ones listed as a whole (layers counts what's inside), changed ones with their properties formatted like Inspect (width 120 → 136, fill #FF0000 → #E03030, text “Welcome” → “Hello”, parent Badge → Screen, order 3 → 1, component Card → Card 2, auto layout, typography, strokes, effects, corner radius, opacity, visibility, name), nested layers and instance contents included. snapshot: false means the frame changed before copies were kept (an older file). show: true opens the compare view in the app: before and now side by side (or overlaid with a slider), changed layers outlined (added green, changed orange, removed red), the list of changes and Resolve change.
• Focus view: dev.focus {id? | direction: next|previous} → {id, name, page, index, count} shows one top-level frame or section alone on the canvas (fitted, selected, other layers neither drawn nor hit), switching page when needed; direction steps through the ready-for-dev frames across pages, wrapping around. dev.unfocus {} ends it, as do Escape (once the frame or nothing is selected), leaving the page or deleting the frame. The app shows a bar with the frame's name and status, Compare changes, previous / next and exit; inspect_ui reports devFocus.

Effects

effect.add {ids?, type? | effect?} adds an effect (dropShadow, innerShadow, layerBlur, backgroundBlur, noise, texture, glass) with its defaults, or the full effect object; effect.set {ids?, index, effect} replaces one. A layer paints its drop shadows first, then its fills, inner shadows, children and strokes (strokes draw over inner shadows), with layer blur, noise and texture over the result.

• Blurs (layerBlur, backgroundBlur) are uniform ({"radius": 8}) or progressive: {"type": "layerBlur", "blurType": "progressive", "startRadius": 0, "radius": 24, "startOffset": [0.5, 0], "endOffset": [0.5, 1]} ramps the radius linearly from startRadius at startOffset to radius at endOffset, points in the layer's unit box (0–1 across and down, like a gradient's handles; before the start and past the end the radius stays). Radii above 10,000 draw as 10,000. In the app, the Design panel's blur row picks Uniform or Progressive, and while a progressive blur's settings are open its start and end points are handles on the canvas. Generated CSS leaves progressive blurs out (CSS blurs are uniform); Inspect lists the ramp.
• Exports: PNG, PDF and SVG draw the same pixels as the canvas. PDF and SVG keep layers vector and embed images for what vectors can't show: background blur and glass (from what lies under the layer: on the page in PDF, among the exported layers in SVG), layer blur, noise and texture in PDF; noise grains (an image over the vector layer), texture and progressive layer blur (the layer whole) in SVG, where uniform layer blur and shadows stay SVG filters.
• PDF for print: a bleed grows each page by that much on every side and shows what lies past the frame there (the frame's fills reach out to the bleed edge with gradients and images in place, its children are clipped to the bleed instead of the frame, nothing is drawn past it); a page of one frame is trimmed to the frame's box (its shadows go into the bleed). Crop marks (at the trim's corners) and bleed marks (at the bleed's) are 0.25 pt hairlines 18 pt long, starting 3 pt outside the bleed, in registration colour. MediaBox is the sheet, BleedBox the trim grown by the bleed, TrimBox the frame. CMYK converts every colour (fills, strokes, text, gradient stops, images and rasterised effects) from sRGB with K = 1 − max(R, G, B), C = (1 − R − K) / (1 − K) (M and Y alike), deterministic and profile-free: the file is DeviceCMYK without an output intent, because embedding one needs a CMYK ICC profile and none ships with FigCraft. Soft masks stay RGB (they aren't printed) and transparency groups blend in RGB, as the PDF writer declares them.

Paint, effect and layout grid lists

A layer's fills, strokes, effects and layout grids are lists kept bottom first: index 0 paints first, the last one is on top (the Design panel lists them the other way round, topmost first).

• Reorder: fill.move, stroke.move, effect.move and grid.move {ids?, from, to} move one item (one undo step for every layer given; out-of-range or equal indices change nothing, negative or fractional ones are refused). The item keeps everything (an image fill its image, scale mode and adjustments, a gradient its stops and handles), and a paint, effect or grid style linked to the list is unlinked (the list no longer matches it). In the app, drag a row by its grip (the empty strip left of its fields); a line shows where it lands.
• Variable bindings follow their items when a list is reordered or an item removed (fill.remove, stroke.remove, effect.remove, grid.remove); a removed item's bindings go with it. Binding fields (variable.bind {field}): fill / stroke (the first paint's colour) or fills/<i>/color / strokes/<i>/color, effects/<i>/<offsetX|offsetY|radius|startRadius|spread|color>, layoutGrids/<i>/<size|count|gutter|offset> (number variables; count is kept to 1–1000, size and gutter are never negative). Moving a bound paint rewrites its key (fill becomes fills/2/color).
• Instance properties: variable.bind {ids: [instance], field: "componentProperties/<name>", variable} drives a boolean property from a boolean variable and a text property from a string variable (other types are refused); the value follows the variable's modes like any binding, the binding follows renames of the property, and deleting the property, resetting the instance or detaching it drops it. The instance's properties panel offers the same with its variable button.

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"fill.move","params":{"ids":[2],"from":0,"to":2}}}}
{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"variable.bind","params":{"ids":[5],"field":"layoutGrids/0/gutter","variable":"gutter"}}}}

Ruler guides

guide.add {vertical, offset, frame? | page?} (returns {index}), guide.move {index, offset, …}, guide.remove {index, …} and guide.clear {…} edit the guides of the current page, another page, or a frame (frames, components and instances). A frame's guides are in its own coordinates: they move with the frame, span only it, are copied with it and snap the layers inside it. On a rotated frame they run along its own axes, and the layers inside it snap to them (and to their siblings and the frame's edges) along those axes, keeping whole pixels in the frame's coordinates. In the app, a guide dragged out of a ruler and dropped on a frame becomes that frame's guide, along the frame's axis nearer the ruler's.

Measuring, the Scale tool, arc handles and selecting

• Measure (what Alt/Option-hover shows): measure.distances {ids? (default the selection), to? (a layer; default the selection's parent)} returns {lines: [{x0, y0, x1, y1, label, dashed}]} in page coordinates, between bounding boxes (several layers by their union, rotated ones by their bounds): one box inside the other measures to each edge, boxes apart measure the gaps (dashed lines extend a gap line to a box it passes beside), overlapping boxes measure between matching edges. measure.padding {id? (an auto layout frame or a child)} returns {frame, lines}: the frame's padding and the gaps between neighbouring children (what Shift+Alt-hover shows). With pointer, alt: true hovers measure (add cmd for nested layers, shift for padding) and alt drags show live distances to the neighbours; inspect_ui reports them under tool.overlay (guides, and measure_box for the box measured to).
• Scale tool (tool.scale, K): dragging a selection handle with pointer scales everything by one factor (sizes and positions whatever the constraints, strokes, effects, corner radii, auto layout spacing, min/max sizes, layout grids, guides, tiled images, text), one undo step per drag, about the anchor point tool.scaleAnchor {anchor?: tl|t|tr|l|c|r|bl|b|br} (or, when the anchor lies on the side being dragged, the opposite handle; alt: true scales from the centre), with the factor and pivot in tool.overlay.scale while dragging. Without dragging, transform.scale {ids?, factor, cx?, cy?} does the same numerically.
• Arc handles: with the Move tool, a single selected ellipse (at least 40 px on screen, unlocked) shows its arc handles, listed by inspect_ui under tool.arcHandles ({id, sweep: [x, y], start, ratio} in page coordinates; start once there is an arc, ratio once there is an arc or a ring). Drag them with pointer. Sweep starts inside the right edge. Dragged round the ellipse, it opens an arc: positive up from the right edge, negative down. It closes again back at the start. Start turns the arc and keeps its sweep. Ratio (the centre, or the inner edge halfway round a ring) drags out to make a ring, and into the gap to show the other part. shift: true snaps angles to 15° steps and the ratio to 5% steps. Each drag is one undo step and writes node.set's arcStart / arcSweep (degrees) and arcInner (0–0.99). tool.overlay.arc holds the readout while dragging ({handle, label: "Sweep 75%", at}), and tool.overlay.arc_hover holds the handle under the pointer.
• Select: select.layersAt {x, y} lists every layer under a page point, front-most first with its depth (the context menu's Select layer); select.set, select.children / select.parent (Enter / Shift+Enter), select.next / select.previous (Tab / Shift+Tab). With pointer, cmd: true clicks select the nested layer, cmd drags from empty canvas select the nested layers they touch, and shift drags toggle what they touch.

Tool failures come back as results with isError: true and a message; protocol problems (unknown tool, malformed JSON, wrong parameter types) are JSON-RPC errors. Nothing crashes the server.

Resources

URI	Content
figcraft://document	The active document (like inspect_document at depth 8).
figcraft://commands	The command catalog.
figcraft://node/{id} (template)	One layer with children to depth 2.
figcraft://command/{id} (template)	One command's docs, e.g. figcraft://command/layout.add.

Prompts

Prompt	Arguments
mobile_screen	screen (required), device (default "iPhone 16"), brand_color
design_system	name, primary
landing_page	product (required), width (default 1440), accent
prototype_flow	screens (comma-separated), transition

Each returns a step-by-step plan naming the exact tools and commands to use and how to verify.

Examples

Create a card with auto layout and check it:

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"create_node","arguments":{
  "type":"frame","name":"Card","x":100,"y":100,"width":320,
  "props":{"fill":"#FFFFFF","cornerRadius":16,"layout":"vertical","padding":24,"gap":12,"sizingV":"hug",
           "effects":[{"type":"dropShadow","color":"#00000026","offset":[0,4],"radius":16}]}}}}
{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"create_node","arguments":{
  "type":"text","parent":2,"text":"Ada Lovelace","props":{"fontSize":24,"fontStyle":"Bold"}}}}
{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"get_node","arguments":{"id":2,"depth":2}}}
{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"screenshot","arguments":{"ids":[2]}}}

A component with an instance whose text is overridden (ids are the ones earlier calls returned; read the instance's text layer id with get_node):

{"jsonrpc":"2.0","id":5,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"component.create","params":{"ids":[2]}}}}
{"jsonrpc":"2.0","id":6,"method":"tools/call","params":{"name":"run_command","arguments":{"command":"instance.create","params":{"component":2,"x":500,"y":100}}}}
{"jsonrpc":"2.0","id":7,"method":"tools/call","params":{"name":"type_text","arguments":{"id":7,"text":"Grace Hopper"}}}

Align and distribute as one undo step:

{"jsonrpc":"2.0","id":8,"method":"tools/call","params":{"name":"batch","arguments":{"label":"Tidy","commands":[
  {"command":"align.top","params":{"ids":[3,4,5]}},
  {"command":"distribute.horizontal","params":{"ids":[3,4,5]}}]}}}

The end-to-end tests in crates/mcp/tests/agent_tasks.rs are worked examples of ten realistic tasks (auto layout, components and overrides, gradients and shadows, paint styles, Light/Dark variables, align/distribute/group, boolean subtract + flatten, export, undo/redo, drawing with tools).