MCP tools¶

The server exposes 26 tools. Each relays to the app's REST API, so they behave like the equivalent action in the UI. All take a project_id. The payloads execute_command accepts are in the command catalog.

One write path

execute_command is the only tool that changes a project. Everything else is a read and is safe to call at any time.

The run_* and slice_* tools go through the app's job registry and poll until the run finishes. They obey the one-expensive-job-per-project rule: if another job holds the project they return {"error": ...} instead of queueing.

Catalog and execution¶

Tool	Signature	Returns
`get_command_catalog`	`()`	The command `type` / `payload` JSON schemas `execute_command` accepts. Versioned with the app, so it is the authority on what this deployment takes.
`execute_command`	`(project_id, type, payload)`	Applies one command. `status` is `accepted` (with `new_revision`) or `rejected` (with a structured reason). `project_id` is filled in automatically; retries once on a stale revision.

Inspect the model¶

Tool	Signature	Returns
`get_model_tree`	`(project_id)`	Parts, sketches, features and their rebuild statuses.
`get_assembly_overview`	`(project_id, assembly_id=None)`	Per assembly: its parts (bounding box, feature/instance counts), sub-assembly occurrences with their placements, and composed bounding boxes. The first call to orient in a multi-part or nested project, before drilling into one part.
`get_motion_state`	`(project_id, assembly_id)`	Every joint in an assembly: current position (`angle` in degrees, `offset` in mm, measured from where the joint was created) and its travel limits (null when unbounded). Read it back after `assembly.joint.set_value` to confirm the mechanism moved.
`get_diagnostics`	`(project_id)`	Features in a non-ok rebuild state (`failed`, `warning`, `unresolved_reference`, `stale`) with structured diagnostics.
`get_topology`	`(project_id, part_id)`	A part's faces (id, surface type, centroid, normal, area, bbox, cylinder info), edge count and bounding box. The starting point for finding geometry to edit.
`find_entities`	`(project_id, part_id, entity, ...)`	Selects faces or edges by predicate (surface/curve type, normal axis, area/length/radius bounds, internal-cylinder, extreme position) instead of guessing indices. The best way to target a hole, top face or fillet edge. A filter belonging to the other entity type (`cyl_internal` on an edge query) is rejected rather than quietly matching nothing.
`get_sketch`	`(project_id, part_id, sketch_id)`	A sketch's elements (type plus 2D params), its plane and constraint count.
`get_command_log`	`(project_id, limit=20)`	Recent commands (type, actor, payload, status, new revision, rejection). Useful to see what just happened or to replay a command.
`list_parameters`	`(project_id)`	Named parameters and their resolved values.
`get_screenshot`	`(project_id, view="multiview", width=1024, height=768)`	Renders the model to a PNG. `multiview` is a 2x2 orthographic sheet (front, top, right, iso); pass a single view (`front`, `back`, `top`, `bottom`, `left`, `right`, `iso`) when that is enough. Use it to check proportions and that features landed where you meant.

Resolve reference geometry¶

Tool	Signature	Returns
`get_face_plane`	`(project_id, part_id, face_id)`	A planar face's sketch plane `{origin, normal, x_dir}`, ready to pass as a `plane_def`. Errors for non-planar faces.
`get_face_axis`	`(project_id, part_id, face_id)`	A cylindrical or conical face's axis `{axis_origin, axis_dir, radius, internal, half_angle?}`. `internal: true` is a hole. Use for concentric cuts, revolve, circular pattern or mirror.
`get_part_references`	`(project_id, part_id)`	Inferred reference geometry: `datum_planes`, `axes`, `holes` (through or blind, with any counterbore/countersink step) and recognized `fillets` / `chamfers`. A starting point for remodeling imported STEP parts; empty for reference-only meshes.

Measure and estimate¶

Tool	Signature	Returns
`measure`	`(project_id, part_id, kind, ...)`	`volume` returns volume, surface area and center of mass; `distance` the minimum distance between two entities; `angle` the angle between them. Entity ids come from `get_topology`.
`estimate_spacing`	`(project_id, part_id, mode, ...)`	Size-aware pattern spacing so copies do not overlap. `linear` returns extent and suggested spacing, `circular` extent and suggested radius. Advisory.
`diff_parts`	`(project_id, part_a_id, part_b_id)`	Geometric diff of two solids overlaid at their local origins: `added_volume`, `removed_volume`, `common_volume`, `symmetric_difference_volume` and `match_ratio` (1.0 = identical). Verifies a parametric remodel against an imported reference. Solids only.
`check_interference`	`(project_id, assembly_id=None, part_ids=None)`	Body pairs tested where the assembly places them, each positioned through its occurrence chain, so a part used several times is checked at each position. Each pair is `clash` (with volume in mm³), `touch`, `clear` (with the gap in mm) or `failed`. Defaults to every root assembly.

Simulation¶

Tool	Signature	Returns
`list_stress_studies`	`(project_id, part_id)`	The stress studies on a part (id, name, fixtures, loads). Call before running one.
`run_stress_study`	`(project_id, part_id, study_id)`	Runs a linear-static study: max von Mises, max displacement, min safety factor and per-face max stress. Define the study first with `simulation.create`.
`list_flow_studies`	`(project_id, part_id)`	The flow studies on a part (id, name, mode, fluid, domain, resolution). Define them with `flow.create`.
`run_flow_study`	`(project_id, part_id, study_id)`	Runs a flow study and returns its scalars and diagnostics. Both modes give `force_n` and `moment_n_mm`; rotation adds `flow_rate_mm3_s` and `torque_n_mm`. Takes minutes (one to ten by resolution preset). It is a design-stage trend tool: a rotating body's torque holds its sign and order of magnitude under refinement, not its figure.

See Materials and stress simulation for the workflow these mirror.

Fabrication¶

Tool	Signature	Returns
`list_slice_setups`	`(project_id, part_id)`	`{printers, setups}` for the project and part. Define them with `slicer.printer.create` and `slicer.setup.create`. Part-scoped; there is no assembly-level equivalent.
`slice_part`	`(project_id, part_id, setup_id)`	Slices a part: stats (layer count, object height, estimated time, filament mm/g, per-role breakdowns), warnings and bed placement. Filament settings come from the part's material; without a printable one it slices as generic PLA and warns. The layer preview is omitted here.