cadcraft

CADCraft

Operate CADCraft through its structured automation interface. Preserve the user's requested drafting workflow and target drawing.

Protocol reference

Read the relevant sections of references/control-protocol.md before constructing calls. This is the downloaded upstream protocol, captured on 2026-10-12.

Source: CADCraft control protocol.

Useful sections: the method table (top of the document), Panel docking, Command-line replies, and Interface language. Relative links inside the downloaded document (e.g. localization.md) refer to upstream documentation; resolve them against https://github.com/storytold/cadcraft/blob/main/docs/ when needed. The document is short and does not list individual drawing commands: discover them at runtime with engine.commands instead of inventing command IDs or parameters.

Locate the executables

cadcraft and cadcraft-cli may not be on PATH even when CADCraft is installed. Discover them before assuming anything is missing, and never invent a path — search for it:

PATH: command -v cadcraft cadcraft-cli (POSIX) or where cadcraft cadcraft-cli (Windows).
macOS: look for CADCraft.app in /Applications and ~/Applications, or run mdfind -name CADCraft.app; the binary inside Contents/MacOS/ is the desktop app.
Linux / Windows: check the usual install locations and the target of any desktop or Start-Menu shortcut.
cadcraft-cli missing is not a blocker. The control port speaks plain line-delimited JSON over loopback TCP and needs no bridge: send one request per line, e.g. {"id":1,"method":"cmdline.input","params":{"text":"circle 0,0 5"}}, and match replies by id and ok. A short script in any language covers every method.

Select the session

For a user's open drawing or visible application, use an existing CADCraft MCP bridge or control session. A headless session has its own in-process drawings and cannot edit the user's live window.
For unattended processing of files, use headless MCP (cadcraft-cli mcp).
Discover available CADCraft tools and installed executables first. If the required connection or executable is missing, report the concrete prerequisite; creating this skill does not install CADCraft or register an MCP server.

Start a desktop session with --control PORT (or CADCRAFT_CONTROL_PORT=PORT); it listens on 127.0.0.1:PORT. Bridge it with:

cadcraft-cli mcp --connect 127.0.0.1:PORT

Reuse a running session when possible and keep TCP on loopback. The upstream protocol documents no authentication handshake or file-access roots; if the installed version requires a token or roots, follow its --help output rather than guessing.

Use CADCRAFT_CONFIG_DIR to point the app at a private, isolated profile for automation (an explicitly empty value disables workspace reads and writes). Do not edit the user's workspace.json directly.

Inspect, edit, and verify

Inspect before editing: drawing.inspect for counts, extents, layers, styles, blocks, layouts, selection, and undo state; ui.inspect for the UI state, active view, and any pending "Save changes?" prompt (closePrompt); cmdline.state for the current prompt. The app may restore or already hold drawings you did not create.

Two ways to edit:

Command line — cmdline.input {text} behaves exactly like a user typing: it starts commands by name or alias and answers prompts (points x,y, relative @dx,dy, polar @d<a, distances, keywords, empty = Enter). Spaces act as Enter except at text prompts. cmdline.script {text} runs a multi-line script; cmdline.key sends Enter or Escape. Always return the command line to the idle Command: prompt (Escape) before the next unrelated operation.
Engine commands — engine.execute {command, params} runs any command with JSON parameters and never opens a dialog. Look up IDs, parameter docs, and enablement via engine.commands.

A refused command-line entry (unknown command, invalid input) still replies "ok": true; always check the error field and output of the reply. app.open without a string path fails with "missing path".

Use ui.menu.invoke only when interactive menu behavior is intended. ui.pointer defaults to world coordinates; ui.click, ui.move, and ui.drag use screen points and reach every widget. ui.key only queues key events — poll ui.inspect or ui.elements for the resulting focus or state before the next action. Use ui.elements (exact-match filters on label, role, focused) to find controls instead of guessing coordinates.

Panel layout (ui.dock, ui.dock.reset, panel IDs toolSets, layers, properties, externalReferences; the canvas is protected) is invoked through engine.execute and does not edit document contents. Change layout, theme, or interface language only when the task requires it.

Verify visually and structurally: re-run drawing.inspect (entities carry handles and geometry) and render with ui.render — a headless render that frames the whole drawing by default (fit: false keeps the current view) and returns pngBase64, or pass path. ui.screenshot captures the app window and needs a presented frame.

File access and output

Desktop control: app.open {path} / app.save {path} / app.quit.
Save output as DXF or DWG: ui.set with saveFormat: "dxf"|"dwg" and saveVersion: "2000"…"2018" set what Save As suggests for new drawings; SAVEAS also accepts version and binary directly.
Report successful saves and the exact output path and format/version. Do not overwrite the user's source drawing unless asked; save a copy under a new name.

Timeouts and uncertain outcomes

The server waits up to 60 s for the app to answer. A timeout reply carries state:

"not-run" — the request was cancelled and will never run; resending is safe.
"may-have-run" — the app had already started it and may still change the drawing (its late result is discarded). Inspect with drawing.inspect before resending any mutation.

After a disconnect or any other unclear failure, inspect drawing and undo state before retrying. Stop and report unresolved state if inspection cannot determine whether replay is safe.