MCP 3D Printer Server

STL Manipulation Tools

All STL tools load the full mesh into memory. Tools that change a model write a new file to the server's temporary directory, named after the input with a suffix such as _scaled, and return its path; the input file is not modified.

get_stl_info

Inspect an STL file without modifying it. Returns the bounding box, dimensions, center, vertex count, and face count.

{
  "stl_path": "/path/to/model.stl"
}

scale_stl

Scale a model uniformly with scale_factor, or per axis with scale_x, scale_y, and scale_z. When any axis value is given, unspecified axes stay at 1.0.

{
  "stl_path": "/path/to/model.stl",
  "scale_factor": 1.2
}

{
  "stl_path": "/path/to/model.stl",
  "scale_x": 1.2,
  "scale_y": 1.0,
  "scale_z": 1.5
}

rotate_stl

Rotate a model around the X, Y, and Z axes, in degrees. Omitted axes default to 0.

{
  "stl_path": "/path/to/model.stl",
  "rotate_x": 0,
  "rotate_y": 0,
  "rotate_z": 90
}

translate_stl

Move a model along the X, Y, and Z axes, in millimeters. Omitted axes default to 0.

{
  "stl_path": "/path/to/model.stl",
  "translate_x": 10,
  "translate_y": 5,
  "translate_z": 0
}

extend_stl_base

Add solid geometry underneath the model to raise and widen its base. extension_inches is in inches and is converted to millimeters (25.4 mm per inch).

{
  "stl_path": "/path/to/model.stl",
  "extension_inches": 0.25
}

merge_vertices

Merge vertices closer together than tolerance (millimeters, default 0.01). This can close small gaps and slightly simplify the mesh.

{
  "stl_path": "/path/to/model.stl",
  "tolerance": 0.01
}

center_model

Move the model so the center of its bounding box is at the origin (0, 0, 0).

{
  "stl_path": "/path/to/model.stl"
}

lay_flat

Find the model's largest flat face and rotate the model so that face rests on the XY plane (Z = 0). Works best on models with a clearly dominant flat face.

{
  "stl_path": "/path/to/model.stl"
}

modify_stl_section

Apply a scale, rotation, or translation to one section of a model: the top, bottom, or center third of its bounding box, or a custom box. value_x, value_y, and value_z are scale factors, degrees, or millimeters depending on transformation_type.

{
  "stl_path": "/path/to/model.stl",
  "section": "top",
  "transformation_type": "scale",
  "value_x": 1.5,
  "value_y": 1.5,
  "value_z": 1.5
}

A custom section requires all six bounds:

{
  "stl_path": "/path/to/model.stl",
  "section": "custom",
  "transformation_type": "rotate",
  "value_x": 0,
  "value_y": 0,
  "value_z": 45,
  "custom_min_x": -10,
  "custom_min_y": 0,
  "custom_min_z": -10,
  "custom_max_x": 10,
  "custom_max_y": 20,
  "custom_max_z": 10
}

generate_stl_visualization

Render an SVG with front, side, top, and isometric views of a model. width and height set each view's size in pixels (default 300).

{
  "stl_path": "/path/to/model.stl",
  "width": 400,
  "height": 400
}

The SVG is a simplified schematic, not a photorealistic render.

Printer Control Tools

Every printer tool accepts host, port, type, and api_key, and Bambu printers also use bambu_serial and bambu_token. Omitted values fall back to PRINTER_HOST, PRINTER_PORT, PRINTER_TYPE, API_KEY, BAMBU_SERIAL, and BAMBU_TOKEN. Keep keys in the server configuration rather than passing them in calls.

What each call does depends on the backend; see printer backend setup for the exact API routes.

Every print start and positive heating command, on every backend, goes through a safety gate: the server inspects the exact G-code it will start, checks each heater target against hardware and material ceilings, checks that the printer is ready, and asks a human to confirm through MCP elicitation. Turning a heater off (temperature: 0), pause_print, and cancel_print are never gated. resume_print reheats and moves the printer, so it only resumes a job this server inspected and started, and asks a person first.

get_printer_status

Read the printer's current status. The response is the backend's own status data: Bambu returns temperatures, job state, progress, layers, time remaining, and AMS data; OctoPrint returns printer state and temperatures; Klipper returns the Moonraker host state only.

{
  "type": "klipper",
  "host": "192.168.1.50",
  "port": "7125"
}

list_printer_files

List the files stored on the printer or its host software. On Bambu printers it lists the cache/, timelapse/, and logs/ directories.

{
  "type": "octoprint",
  "host": "192.168.1.100"
}

upload_gcode

Upload G-code to the printer, and optionally start it. Pass gcode_path for a local file, or gcode with the content (or a local path). filename defaults to the basename of gcode_path; when printing, use a plain filename so the started file is exactly the uploaded one.

{
  "type": "klipper",
  "host": "192.168.1.50",
  "port": "7125",
  "gcode_path": "/path/to/benchy.gcode",
  "print": true,
  "material": "PETG"
}

• Without print, the file is only uploaded and nothing is inspected or started.
• With print: true, the exact uploaded bytes are inspected first (every S and R heater target, tool changes, and hardware and material ceilings), the printer's state is checked, and a human confirms before the job starts.
• Printing needs a declared material: slicer metadata in the file (; filament_type = PLA) or the material argument, which must not contradict the file.
• On Bambu printers, files go to cache/ over FTPS, and printing also needs the model (bambu_model or BAMBU_MODEL). Automatic printing after upload supports .gcode only; print .3mf projects with print_3mf.
• The result's jobName is the remote file name. counterpart_print_progress reports the same name as job.name while that job runs.

start_print

Start a G-code file that is already stored on the printer. The server downloads that exact file, inspects it, checks the printer's state, asks a human to confirm, and then starts a uniquely named checked copy. This works on Bambu Lab, OctoPrint, Klipper (Moonraker), and Duet. Repetier, Prusa, and Creality refuse, because their adapters have no verified download route; use upload_gcode with print: true instead.

{
  "type": "octoprint",
  "host": "192.168.1.100",
  "filename": "benchy.gcode",
  "material": "PLA"
}

Pass material when the file has no filament_type metadata. On Bambu printers it also needs the model and supports .gcode files only; bare filenames are looked up in cache/. The result's jobName is the checked copy's name (checked-<id>-<file>), which is the name the printer reports for the job.

cancel_print

Cancel the current print job. Cancelling is never gated and also cancels checked prints still waiting to start, including a pending resume_print. A cancelled job cannot be resumed; use pause_print to stop temporarily.

{
  "type": "prusa",
  "host": "192.168.1.120"
}

pause_print

Pause the current print. Pausing is never gated. Routes: OctoPrint POST /api/job ({"command":"pause","action":"pause"}), Moonraker POST /printer/print/pause, PrusaLink PUT /api/v1/job/<id>/pause, Duet M25, Repetier @pause, and Creality printers that run Moonraker. Bambu pause is in bambu-printer-mcp.

{
  "type": "klipper",
  "host": "192.168.1.50",
  "port": "7125"
}

resume_print

Resume a paused print. Resume reheats and moves the printer, so it is gated like a print start. It resumes only the job this server instance inspected and started, after a fresh report that the same job is paused, and after a person confirms through MCP elicitation (unless the server sets PRINT_REQUIRE_CONFIRMATION=0). OctoPrint, Klipper and Duet re-download the file and compare its SHA-256 with the inspected bytes before asking; PrusaLink, Repetier and Creality have no download route here, so the job is matched by name only. The printer is read again after the confirmation. Cancelling the job, or a report that it ended, retires it, so a later job that reuses the name is never resumed. A job started at the printer, from another app, or before the server restarted is refused; resume it at the printer. Duet's download route needs the Duet Software Framework, so a standalone board's resume is refused. The result's bytesVerified says whether the bytes were re-read. OctoPrint drops a resume sent while it is still pausing, so the server waits for a settled pause (job.stage "Pausing" means not yet). Routes: OctoPrint {"command":"pause","action":"resume"}, Moonraker POST /printer/print/resume, PrusaLink PUT /api/v1/job/<id>/resume, Duet M24, and Repetier continueJob.

counterpart_printer_info

Describe the printer in the shared counterpart/1 shape: the server's name and version, the printer's kind, host and any model, serial or name it reports, and which features work. Capabilities are detected from the firmware, never assumed. For example, camera is http-snapshot only when the firmware names a snapshot URL or the conventional one answers with a JPEG.

{
  "contract": "counterpart/1",
  "server": { "name": "mcp-3d-printer-server", "version": "1.2.21" },
  "printer": { "kind": "klipper", "host": "192.168.1.50", "name": "voron" },
  "capabilities": { "progress": true, "layers": true, "camera": "http-snapshot", "filaments": "single",
                    "pause": true, "resume": true, "cancel": true, "print3mf": false, "gcode": true }
}

counterpart_print_progress

Read the printer's state and current job in one shape for every firmware. state is one of idle, preparing, printing, paused, finished, failed, cancelled, offline, or busy. job carries the file name (the same as the upload's jobName), progress (0 to 100), elapsedSec, remainingSec, layer and totalLayers where the firmware reports them, and stage for transitional states. problems lists firmware errors and messages. Optional fields are omitted, never null. A printer that does not answer at all is offline. See progress, camera, pause and resume for each firmware's requests and mapping.

{
  "contract": "counterpart/1",
  "observedAt": "2026-11-01T12:00:00.000Z",
  "state": "printing",
  "job": { "name": "checked-4f2a-bracket.gcode", "progress": 25, "elapsedSec": 1200, "remainingSec": 3600, "layer": 12, "totalLayers": 80 },
  "temps": { "nozzle": { "actual": 215, "target": 215 }, "bed": { "actual": 60, "target": 60 } },
  "problems": []
}

camera_snapshot

Capture one JPEG frame and return it as base64, with the same arguments and result as bambu-printer-mcp's camera_snapshot plus capturedAt. Pass save_path to also write the file, and timeout_ms (default 8000).

• OctoPrint: the Classic Webcam snapshot URL on 1.9 and later (plugins.classicwebcam.snapshot), webcam.snapshotUrl on 1.8, then http://<host>/webcam/?action=snapshot.
• Moonraker: the first enabled webcam's snapshot_url from /server/webcams/list.
• Repetier: the printer's webcam staticUrl.
• PrusaLink and Duet have no local snapshot API.
• PRINTER_CAMERA_SNAPSHOT_URL overrides the source for any printer.

Relative URLs and loopback hosts in the firmware's settings are read as the printer itself. The API key is sent only to the printer's own API address, and only a JPEG is accepted.

{ "status": "success", "format": "image/jpeg", "sizeBytes": 78719, "base64": "/9j/4AAQ…", "capturedAt": "2026-11-01T12:00:00.000Z", "source": "moonraker-webcam" }

get_printer_filaments

Report the loaded filament as one external slot, {"slots": [{"id": "ext", "material", "color", "name", "source", "profile"}]}. Moonraker printers with Spoolman report the active spool's material, #RRGGBB colour and name (source: "spoolman"); every other printer reports source: "unknown". Bambu AMS inventory is in bambu-printer-mcp.

Each slot also carries profile: the absolute path of the installed slicer filament profile for its material, which slice_stl takes as load_filaments. It is resolved in the slicer slice_stl uses by default (SLICER_TYPE, SLICER_PATH), for the printer in SLICER_PROFILE. OrcaSlicer searches its bundled profiles/<vendor>/filament, the OrcaSlicer/system copies and the user's OrcaSlicer/user/<id>/filament presets, reading filament_type and compatible_printers through inherits. PrusaSlicer and Slic3r search the data folder's filament/*.ini presets. The material must equal the profile's filament_type exactly (case aside): a PLA spool never gets a PLA-CF profile. Profiles that list other printers are skipped; one that lists this printer comes first, then profiles for every printer, user presets before bundled ones. With no reported material, profile is the filament slice_stl loads by default (FILAMENT_PROFILE), when that file exists. When nothing resolves, profile is omitted.

set_printer_temperature

Set a target temperature for a printer component. Use bed or extruder; Bambu also accepts nozzle, tool, and tool0. OctoPrint nozzle targets are sent to tool0.

{
  "type": "klipper",
  "host": "192.168.1.50",
  "port": "7125",
  "component": "extruder",
  "temperature": 215,
  "material": "PLA"
}

• temperature must be a finite number of 0 or more. 0 switches the heater off and is never gated.
• Positive targets are checked before connecting against independent hardware ceilings and the material's ceiling, need a ready printer, and ask a human to confirm.
• Positive nozzle heating needs material (for example PLA, PETG, or ABS), including for spools without RFID.
• On Bambu printers, positive heating also needs bambu_model (or BAMBU_MODEL), and nozzle heating uses nozzle_diameter (0.2, 0.4, 0.6, or 0.8; default NOZZLE_DIAMETER or 0.4). Both are checked against the live printer.

Bambu-Specific Tools

These tools work with PRINTER_TYPE=bambu (or type: "bambu"). Set up LAN Only Mode, the serial number, the access code, and the model as described in Bambu Lab setup.

print_3mf

Upload a sliced .3mf project to a Bambu printer over FTPS and start it with an MQTT project_file command that carries the plate's G-code path, its MD5, the AMS mapping, and the calibration flags. bambu_model is required (or BAMBU_MODEL); without it the server asks through MCP elicitation when the client supports it, or returns an error. The wrong model can crash the bed into the nozzle.

Before anything is uploaded, the server inspects a private copy of the selected plate (model, nozzle, bed type, materials, and every heater target). It checks them against per-model hardware limits, material ceilings, and a fresh MQTT report of the printer's model, serial, nozzle, state, errors, and loaded filament. A human then confirms, and the report is checked again before dispatch.

{
  "three_mf_path": "/path/to/bracket.gcode.3mf",
  "bambu_model": "p1s",
  "bed_type": "textured_plate",
  "use_ams": true,
  "ams_mapping": { "Generic PLA": 0 },
  "bed_leveling": true,
  "flow_calibration": true,
  "vibration_calibration": true,
  "layer_inspect": true,
  "timelapse": false
}

• If the project has no plate G-code, the server tries to auto-slice it with FULU OrcaSlicer-bambulab or Bambu Studio. If slicing fails, or the selected plate still has no G-code, it stops with an error and never uploads the original project.
• ams_mapping is an object whose values are AMS slot numbers. When it is omitted, the mapping embedded in the 3MF is used; with no mapping at all, the print runs without AMS. use_ams: false turns AMS off.
• After sending the command, the server watches fresh reports for up to 15 seconds (BAMBU_DISPATCH_CHECK_MS) and returns dispatch: "started" or "unconfirmed". If the firmware refuses the command (HMS 0500-0500-0001-0007 on firmware 01.08.05 and later without Developer Mode), the call fails and says so; the checked file stays on the printer's storage.
• nozzle_type (stainless_steel, hardened_steel, tungsten_carbide, brass) sets the installed nozzle when the project must be auto-sliced. The job's nozzle type must match the printer's report.
• bed_type is one of textured_plate, cool_plate, engineering_plate, or hot_plate (default BED_TYPE, else textured_plate). It must match the plate's bed metadata, so a file sliced for another plate, or without bed metadata, is refused until bed_type matches.
• nozzle_diameter accepts 0.2, 0.4, 0.6, or 0.8 (default NOZZLE_DIAMETER or 0.4).
• Calibration flags default to on (timelapse to off) when omitted.
• layer_height, nozzle_temperature, bed_temperature, and support_enabled are accepted but not applied: those settings are baked into the sliced file. Change them in the slicer.
• A success response means the command was sent, not that the print started cleanly. Check the printer's status afterward.

check_fulu_orca_setup

Inspect a FULU OrcaSlicer-bambulab install: the executable, the platform runtime payload, the install and verify commands, and optionally a BambuNetwork bridge handshake. Paths default to the server environment; see checking the setup.

{
  "platform": "darwin",
  "run_bridge_probe": true
}

bridge_command, and slicer_path, plugin_dir, or runtime_dir with run_bridge_probe: true, require MCP_ALLOW_EXECUTABLE_ARG=1.

fulu_bambu_network_rpc

Call one FULU BambuNetwork bridge method for diagnostics. Read-only methods such as bridge.handshake, bridge.runtime_info, and net.get_user_print_info are allowed by default. Agent and session setup methods require allow_mutating_method: true. Raw print methods (such as net.start_print), printer messages (net.send_message), file transfers, and unknown methods are refused, because they would bypass the print safety gate; print with print_3mf. bambu_model is informational only. See bridge RPC.

{
  "method": "bridge.handshake"
}

The bridge command comes from FULU_BAMBU_BRIDGE_COMMAND; a per-call bridge_command requires MCP_ALLOW_EXECUTABLE_ARG=1.

Slicing Tools

See the slicing guide for slicer types, profiles, and troubleshooting. Slicing a file yourself in the slicer's GUI and uploading the result is the most predictable path.

slice_stl

Slice an STL or 3MF with the configured slicer and return the output path: G-code for PrusaSlicer, Slic3r, generic OrcaSlicer, and CuraEngine, or a sliced .3mf for the Bambu-compatible path.

The Bambu-compatible path is used for Bambu Studio, FULU OrcaSlicer-bambulab, and OrcaSlicer when the call passes bambu_model:

• The machine preset always comes from bambu_model (or BAMBU_MODEL, asked for when missing) and nozzle_diameter (default NOZZLE_DIAMETER or 0.4). The exact <model> <diameter> nozzle preset must exist in the selected slicer installation. Its inherits and include chains are resolved before the slicer runs.
• slicer_profile (or SLICER_PROFILE) is a process profile only. A machine;process list is rejected with instructions.
• Slicing accepts p1s, p1p, p2s, x1c, x1e, a1, a1mini, h2d, h2s, and h2c when the installed slicer has that preset. Printing still accepts only the seven models in BAMBU_MODEL.
• The output must contain a nonempty Metadata/plate_<n>.gcode. Failures stop with the slicer's exit code or signal, the tails of its output, and slicing-specific advice.

{
  "stl_path": "/path/to/phone-case.stl",
  "slicer_type": "bambustudio",
  "bambu_model": "p1s",
  "nozzle_diameter": "0.4",
  "bed_type": "textured_plate",
  "load_filaments": "/path/to/filaments/tpu-95a-hf.json",
  "arrange": true,
  "orient": false
}

Options for the Bambu-compatible path:

layer_height (mm), wall_loops (a whole number), and sparse_infill_density (such as "15%") are written over the selected profile on every slicer: as the process keys layer_height, wall_loops, and sparse_infill_density for Bambu Studio and OrcaSlicer, and as --layer-height, --perimeters, and --fill-density for PrusaSlicer and Slic3r. They win over a template. Cura refuses them; set them in its definition file. Your profile files are never modified.

Generic slicers keep their own profile formats: PrusaSlicer and Slic3r load one exported config, plus an optional filament preset .ini from load_filaments, and generic OrcaSlicer takes machine.json;process.json, optionally followed by |filament.json. slicer_type, slicer_profile, and filament_profile fall back to SLICER_TYPE, SLICER_PROFILE, and FILAMENT_PROFILE. The slicer executable comes from SLICER_PATH; a per-call slicer_path requires MCP_ALLOW_EXECUTABLE_ARG=1. See the slicing guide.

slice_with_template

Slice an STL or 3MF with a named template from the local template registry. The template supplies the process settings; the machine preset still comes from bambu_model and nozzle_diameter. It takes the same arguments as slice_stl, and an explicit slicer_profile in the call overrides the template.

{
  "stl_path": "/path/to/bracket.stl",
  "template_name": "p1s-petg-strong",
  "bambu_model": "p1s"
}

list_templates

List the saved slicing templates (.3mf, .json, .config) in the registry directory, BAMBU_TEMPLATE_DIR (default ~/Sync/bambu/templates), or in template_dir.

{}

save_template

Copy a local .3mf, .json, or .config file into the template registry. template_name defaults to the source filename without its extension.

{
  "source_path": "/path/to/p1s-petg-strong.3mf",
  "template_name": "p1s-petg-strong"
}

get_slice_settings

Read the slicer settings in a 3MF, an extracted project_settings.config, or a profile JSON without slicing: layer height, infill, walls, supports, brim, bed, printer, and filaments. Pass source_path, or template_name to read a saved template.

{
  "template_name": "p1s-petg-strong"
}

confirm_temperatures

Report every heater target in a G-code file: S and R forms, tool-addressed targets, RepRapFirmware G10/M568, and Klipper SET_HEATER_TEMPERATURE. An expected extruder_temp or bed_temp matches only when it equals the file's highest target, which the result returns as peak. It is read-only; the printing tools enforce their own safety gate.

{
  "gcode_path": "/path/to/model.gcode",
  "extruder_temp": 240,
  "bed_temp": 80
}

process_and_print_stl

Extend an STL's base, slice it, and print it through the same checked print gate as upload_gcode and print_3mf, including the human confirmation. If you pass extruder_temp or bed_temp, each must equal the sliced job's highest target (S and R forms, every tool); a mismatch stops before anything is uploaded. Pass material when the sliced G-code has no filament_type metadata. On a Bambu printer with a Bambu-compatible slicer, the sliced .3mf goes through the print_3mf checks, and the printer model is required.

{
  "stl_path": "/path/to/model.stl",
  "extension_inches": 0.1,
  "extruder_temp": 210,
  "bed_temp": 60,
  "material": "PLA",
  "type": "octoprint",
  "host": "192.168.1.100"
}

Use slice_stl, confirm_temperatures, and upload_gcode separately when you want to review the sliced file before the print is offered for confirmation.

Advanced Tools

Blender MCP

Connect a standard stdio Blender MCP server with BLENDER_MCP_COMMAND (for example, the full path to uvx) and BLENDER_MCP_ARGS (for example ["mcp-for-blender"]). The mcp-for-blender project was formerly published as blender-mcp, which still works as a compatibility wrapper. Install and enable its addon in Blender and start the addon's connection. Blender and this server must be able to read the same local files. Printer tools work without Blender configured. Keep Blender open while your agent works: the addon does not run in background mode. See the Blender guide for setup, units, and a worked example that refits a phone case for a new phone end to end.

blender_mcp_status

Inspect the Blender MCP configuration. With connect: true, it starts the configured server, initializes it, and lists its tools by name and summary. Pass tool_names to get the full input schemas of the tools you are about to call (include_schemas: true returns all of them, which is large). A successful connection does not prove the addon inside Blender is running; call get_scene_info through blender_mcp_call to check that.

{
  "connect": true,
  "tool_names": ["execute_blender_code"]
}

blender_mcp_call

Call a tool the Blender MCP server advertises, such as get_scene_info or execute_blender_code, with arguments matching its discovered schema. The full MCP result, including images and errors, is returned. Calls can change the active Blender scene and are never retried automatically. Preserve the user's own words in user_prompt when the remote tool asks for it.

{
  "tool_name": "get_scene_info",
  "arguments": { "user_prompt": "Inspect the scene before preparing a print." }
}

blender_mcp_export_stl

Export named objects from the live Blender scene to a new STL for slicing. Use it after modelling or editing through blender_mcp_call; Blender MCP's own export_scene writes GLB or FBX, not STL. The export writes world-space geometry with modifiers applied, without changing the scene, selection, or mode.

{
  "object_names": ["PhoneCase"],
  "output_path": "/path/to/phone-case.stl",
  "user_prompt": "Make it fit my iPhone 17 Pro Max."
}

• The result reports output_verified: true, the triangle count, and bounding_box.dimensions measured from the written file. Compare the dimensions with what you expect before slicing.
• STL files carry no units and slicers read them as millimetres. An imported STL keeps its numbers, so the default scale: 1 is right. If a part was modelled in metres, the result warns that it is under 1 unit across; export again with scale: 1000.
• output_path must be new and its parent must exist; nothing is ever overwritten. On any Blender error, mismatched receipt, or invalid file, nothing is published.

blender_mcp_edit_model

Import an STL into Blender, apply ordered edits, and export a new STL. Supported operations are decimate:<ratio> (greater than 0, up to 1), remesh:<voxel size> (positive, in STL units), and boolean_union:<STL path>. Use blender_mcp_call for anything else.

{
  "stl_path": "/path/to/model.stl",
  "output_path": "/path/to/model-edited.stl",
  "operations": ["decimate:0.5"],
  "user_prompt": "Reduce the triangle count for printing.",
  "execute": false
}

• The default (execute: false) validates the request and returns the plan and generated Python without launching Blender. Set execute: true to apply it, reusing the preview's output_path.
• Omitting output_path selects a unique model-edited-<id>.stl beside the input. Existing input and output files are never overwritten.
• The edit requires Object Mode, preserves existing scene objects and selection, and publishes the new STL only after checking a matching export receipt and a valid, finite triangle mesh. Binary STLs up to 256 MiB are validated in small chunks; ASCII STLs are limited to 4 MiB.
• Requests have connection, discovery, and call deadlines (BLENDER_MCP_TIMEOUT_MS, default 120000) that also cover file validation. Interrupted edits are never replayed; inspect Blender before retrying, because an edit may already have started.
• A valid STL is not proof of printability. Inspect the result before slicing.

Legacy BLENDER_MCP_BRIDGE_COMMAND shell commands remain supported when no standard command is configured. They receive JSON on stdin (modelPath, operations, source, and stlPath) and the same JSON in MCP_BLENDER_PAYLOAD, and their results report output_verified: false. A per-call bridge_command requires MCP_ALLOW_EXECUTABLE_ARG=1.

Fusion MCP

Design parts from scratch in Autodesk Fusion through faust-machines/fusion360-mcp-server, pinned to commit 19b9f1e95192. Set FUSION_MCP_COMMAND to the full path of uvx; FUSION_MCP_ARGS defaults to the pinned server in socket mode. Install that commit's Fusion360MCP add-in in Fusion and set it to Run on Startup. The client stays connected for the life of this server, only FUSION_* settings reach the Fusion server, and requests are never replayed. See the Fusion guide for setup, units, and the open-document requirement.

fusion_mcp_status

Report configured, connected, addinReachable, fusionRunning, the Fusion server's tools with their schemas, launched, pin (the faust-machines commit), and error when the server could not start. addinReachable means the add-in answered its own ping within 2 s on FUSION_MCP_PORT (default 9877, because Blender's MCP addon holds 9876). connected is true only when the add-in also answered through the Fusion server. With launch: true and Fusion not running on this Mac, it runs open -a "Autodesk Fusion" --env FUSION_MCP_PORT=<port> and waits up to 90 s for the add-in.

{ "launch": true }

fusion_mcp_call

Call any tool the Fusion server advertises, such as create_sketch, extrude, fillet, set_parameter, or execute_code, with arguments matching its discovered schema. The full MCP result and errors are returned, as for blender_mcp_call. Calls change the active design and are never retried. Fusion lengths are in centimetres unless a tool says otherwise.

{ "tool_name": "create_sketch", "arguments": { "plane": "xy" } }

fusion_mcp_new_design

Open a new parametric design document, so the Fusion tools have an active design. At the pinned commit, Fusion must already have some document open: no tool works from Fusion's home screen (issue #12).

fusion_mcp_export

Write <name>.stl (from export_stl), <name>.f3d (from export_f3d), and <name>.parameters.json (the design's user parameters) into output_dir, and return their absolute paths as stl, f3d, and parameters. The STL is one body: the only visible solid body, or body_name, whose name must be unique across all bodies, hidden ones and component copies included. It is checked as a finite triangle mesh, and stlUnits reports whether its numbers are millimetres. Existing files are never overwritten, and a failed export publishes nothing.

{ "output_dir": "/path/to/project", "name": "bracket" }