OneCAD-Draft/docs/automation/README.md

OpenCADStudio MCP control

Every native OpenCADStudio build contains the same MCP server as the editor. OpenCADStudio --mcp starts it over stdio, opens the desktop editor when needed, and exposes the live document without Python, a package manager, a sidecar service, or client-specific code.

MCP lets an AI client inspect the open drawing, execute editor commands, and verify the result through a shared protocol. Install OpenCADStudio, then add a local MCP server in the client and set its command to:

OpenCADStudio --mcp

The client must start that command over standard input/output. If it asks for the executable and arguments separately, select the installed OpenCADStudio executable and enter --mcp as its only argument. The exact registration screen or configuration location belongs to the client. Once connected, the four tools below should appear in the client's MCP tool list.

The server provides four tools:

• ocs_sessions finds running editor sessions and opens OpenCADStudio when none exists.
• ocs_read reads document state, commands, entities, layers, properties, measurements, history, events, and operation status.
• ocs_execute performs semantic commands and input against the real editor.
• ocs_capture returns a PNG of the current window for visual verification.

Mutations carry a session ID, document ID, expected revision, selection, and idempotent request ID. Commands report waiting_input while more input is required and asynchronous work remains running until its real callback finishes. Geometry stays in OpenCADStudio and its geometry kernel.

The source-tree protocol smoke test uses only the Python standard library:

cargo build
python3 docs/automation/mcp_smoke.py target/debug/OpenCADStudio