OrcaSlicer MCP

Drive OrcaSlicer with AI. OrcaSlicer MCP is an MCP server that lets Claude (Desktop or Code — or any MCP client) operate a real, running OrcaSlicer: load models, arrange the plate, tune settings, slice, and analyze the result — live, with every change visible in the GUI.

The slicer stays authoritative and on your machine. The server contains no LLM and makes no cloud calls; it talks only to OrcaSlicer on localhost (or a host you explicitly allow).

How it works

Two pieces:

1. The OrcaSlicer MCP build of OrcaSlicer — OrcaSlicer 2.3.2 with an embedded local control API (token-authenticated, localhost-only by default). Get it from the releases page; if no binary is up for your platform yet, build the remote-api branch from source.
2. This package (orcaslicer-mcp) — the MCP server that connects your AI client to that build.

Stock OrcaSlicer does not have the control API — the MCP server requires the build above.

Updating: always get new builds from the releases page, never from inside the app. Builds mcp.2 and later disable OrcaSlicer's built-in updater for you (left on, it offers stock OrcaSlicer — which removes the control API). If you're on an older build and a "new version available" prompt appears, click Skip this Version.

Quickstart

You'll need uv installed (it provides the uvx command that runs the server) — one line: curl -LsSf https://astral.sh/uv/install.sh | sh on macOS/Linux, or irm https://astral.sh/uv/install.ps1 | iex in PowerShell on Windows.

1. Install and launch the OrcaSlicer MCP build, and complete the one-time first-run setup (pick your printer). On a fresh install OrcaSlicer may show a "Bambu Network Plug-in Required" dialog — click Skip for Now; that plug-in is only for Bambu cloud printing and isn't needed here. (The control API starts once first-run setup is finished.)

2. In OrcaSlicer: Preferences (Ctrl+P) → Remote API → Enable Remote API, then copy the API token shown on that page. (Access is localhost-only unless you also switch on "Allow LAN access".)

3. Add the server to your MCP client config (Claude Desktop claude_desktop_config.json, or a project .mcp.json for Claude Code):

   {
     "mcpServers": {
       "orcaslicer": {
         "command": "uvx",
         "args": ["orcaslicer-mcp"],
         "env": {
           "ORCA_API_TOKEN": "<token from Preferences>"
         }
       }
     }
   }
   

   ORCA_API_URL defaults to http://127.0.0.1:13130 — set it only if you changed the port, or run OrcaSlicer on another machine (with LAN access enabled there).

   macOS note: Claude Desktop doesn't inherit your terminal's PATH, so "command": "uvx" can fail silently (Claude acts as if the server doesn't exist). Use the full path instead: run which uvx in Terminal (usually ~/.local/bin/uvx or /opt/homebrew/bin/uvx) and put that path in "command". Then quit Claude Desktop fully (Cmd-Q) and reopen.

4. Restart your client and ask: “Load benchy.stl, slice it with the current profile, and tell me the print time.”

What Claude can do with it

• Plate & models: load_model, list_objects, transform_object, duplicate_object, delete_object, arrange_plate, auto_orient, check_placement, diagnose_plate, get_job_status
• Settings: get_config, set_config, find_config_keys, describe_setting, search_settings, compare_settings, set_layer_height, set_height_range, set_object_config (per-object overrides)
• Presets: list_presets, select_preset, get_preset_config, edit_preset, save_preset, rename_preset, delete_preset
• Slicing: slice, slice_and_wait, apply_and_slice, cancel_slice, get_slice_status, get_slice_warnings, get_slice_breakdown (per-feature time/flow analysis), get_gcode
• Live state & events: get_status, watch_events

Settings intelligence

• consult(query) — curated slicing knowledge plus your saved notes, composed per topic, symptom, or goal.
• check_profile_physics(changes?) — deterministic sanity gate: overlays proposed changes on the live config and runs flow/temperature/geometry/cooling math. Verdict: ok, warnings, or blocked.
• remember(note, scope) — persist machine/user/project facts for future sessions as plain local files in ~/.orcaslicer-mcp/notes/ (relocatable via ORCA_MCP_NOTES_DIR).

Plus an offline settings reference: authoritative label/tooltip/type/range/enum/default for ~800 OrcaSlicer settings, bundled with the package.

Security

• The control API binds 127.0.0.1 only by default; LAN access is an explicit opt-in in Preferences.
• Every request must carry the API token; OrcaSlicer generates it on first run and can regenerate it at any time.
• The MCP server is a local stdio process. No telemetry, no cloud.

Development

uv venv && uv pip install -e ".[dev]"
uv run pytest   # unit tests (mock API) + a guarded live smoke test

The live smoke test is skipped unless ORCA_API_URL / ORCA_API_TOKEN point at a running OrcaSlicer MCP build.

Developer docs — protocol notes, design specs, verification results — live in docs/.

Status

Early public release (soft launch). The server is exercised by ~170 unit tests and real print workflows; prebuilt OrcaSlicer MCP builds are available for Windows, macOS, and Linux on the releases page. Issues and reports welcome.

License

AGPL-3.0 — the same license as OrcaSlicer, from whose source the bundled settings schema is derived. See LICENSE.