Skip to main content
Glama

OwlCAD

by com.owlcad.mcp
OverviewDiscussionsAdmin

Check for collisions

check_interference
Read-onlyIdempotent

Find which top-level parts physically overlap, and by how much volume. This is the assembly check you cannot do by reasoning about a tree OR by looking at a render — an interference is usually hidden inside the model. Run it on anything with more than one part that is meant to fit together.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
scadNoOpenSCAD source, as an alternative to `nodes` (supply exactly one). Interpreted by the same engine the editor’s .scad import uses; BOSL2/MCAD includes resolve. minkowski() and resize() are not supported here — use hull() or offset().
nodesNoParametric node tree. mm, Z-up, rotations in DEGREES (a rotation.* binding: radians). Read owlcad://schema/primitives for every primitive, modifier and generator and its parameter ranges (unknown params are dropped silently), and owlcad://schema/conventions for the placement arithmetic, which is where most models go wrong.
projectIdNoId of one of your saved projects, as an alternative to `nodes`/`scad` (supply exactly one).
smoothnessNoCurve quality for shapes that left their segment count automatic. Defaults to "standard", which is the editor default — pass "high" to match a project authored at high smoothness, "draft" for a cheaper check.
minVolumeMm3NoIgnore overlaps smaller than this (default 0.001). Parts that merely share a face graze each other numerically; this is what stops that being reported as a collision.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedInput schema / properties / nodes / description
      Previous value: -"Parametric node tree. mm, Z-up, rotations in DEGREES. Read owlcad://schema/primitives for every primitive, modifier and generator and its parameter ranges (unknown params are dropped silently), and owlcad://schema/conventions for the placement arithmetic, which is where most models go wrong."New value: +"Parametric node tree. mm, Z-up, rotations in DEGREES (a rotation.* binding: radians). Read owlcad://schema/primitives for every primitive, modifier and generator and its parameter ranges (unknown params are dropped silently), and owlcad://schema/conventions for the placement arithmetic, which is where most models go wrong."
  2. Changed1 schema field changed
    • changedInput schema / properties / nodes / items / properties / generatorKey / description
      Previous value: -"Generator to expand (kind=generator). PREFER one over hand-building the same thing — they carry standards dimensions and solve fits a tree of primitives gets subtly wrong: gearTrain · planetary · rackPinion · wormDrive · herringbone · herringboneTrain · pulley · bearing · belt · spring · adapter · boardMount · enclosure · gridfinity · threadedJar · pinHinge · snapFit · ballSocket · fastener · textPlate · fitCoupon · calibrationBlock · clamp · impeller · axialFan · fanFrame · plugCap."New value: +"Generator to expand (kind=generator). PREFER one over hand-building the same thing — they carry standards dimensions and solve fits a tree of primitives gets subtly wrong: gearTrain · planetary · rackPinion · wormDrive · herringbone · herringboneTrain · pulley · bearing · belt · spring · adapter · boardMount · enclosure · gridfinity · threadedJar · pinHinge · snapFit · ballSocket · fastener · textPlate · fitCoupon · calibrationBlock · clamp · impeller · axialFan · fanFrame · plugCap · pillowBlock."
  3. Changed1 schema field changed
    • changedInput schema / properties / scad / description
      Previous value: -"OpenSCAD source, as an alternative to `nodes` (supply exactly one). Interpreted by the same engine the editor’s .scad import uses. minkowski() and resize() are not supported here — use hull() or offset()."New value: +"OpenSCAD source, as an alternative to `nodes` (supply exactly one). Interpreted by the same engine the editor’s .scad import uses; BOSL2/MCAD includes resolve. minkowski() and resize() are not supported here — use hull() or offset()."
  4. First observed

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds domain context ('an interference is usually hidden inside the model') but no tool behavior such as cost, latency, or result format. With annotations carrying the burden, a 3 is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, zero waste, with the core purpose front-loaded before the justification and the usage cue. Nothing is repeated or padded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only check with 100% schema coverage, the main remaining burden is what comes back, since there is no output schema. The description conveys the shape of the result (which parts overlap and by how much volume), which is enough to call it correctly, though return format details are left implicit.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all five parameters in detail (including minVolumeMm3's grazing rationale and smoothness defaults). The description's 'by how much volume' loosely maps to minVolumeMm3 but adds no syntax or format detail beyond the schema. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Find which top-level parts physically overlap, and by how much volume') and goes further to distinguish the operation from what sibling capabilities can achieve ('cannot do by reasoning about a tree OR by looking at a render'). An agent can tell this apart from render/measure/evaluate without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear triggering condition: 'Run it on anything with more than one part that is meant to fit together.' It also implicitly rules out tree reasoning and rendering as substitutes. It stops short of naming the adjacent sibling tools (measure, print_check) as alternatives, so it is strong but not fully explicit routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All OwlCAD toolsInspect
Try in Browser
One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources