Create a constant-radius native helix around a world-space axis in millimeters by defining start/end points, radius, turns, and handedness for CAD geometry.
Create a constant-radius native helix around a world-space axis. Coordinates and radius are millimeters.
| Name | Required | Description | Default |
|---|---|---|---|
| turns | Yes | ||
| intent | No | ||
| radiusMm | Yes | ||
| revision | Yes | ||
| axisEndMm | Yes | ||
| handedness | No | right | |
| axisStartMm | Yes | ||
| radialDirection | No |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=true, openWorldHint=false, so the agent knows this mutates the document. The description usefully adds that coordinates and radius are in millimeters and that the axis is world-space, which the annotations do not cover. It does not disclose whether a curve or solid body is produced, nor any revision/concurrency behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two tight sentences, front-loaded with the action and followed immediately by the unit convention. No filler or restatement of the tool name.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a destructive 8-parameter creation tool with no output schema and 0% schema coverage, the description omits far too much: what the 'revision' parameter is for, handedness/radialDirection defaults, and what geometry (curve vs. solid) results. An agent could not call this confidently without inspecting the schema for every field.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0% across 8 parameters, so the description must carry the burden and it only partially does: it clarifies units for axisStartMm/axisEndMm/radiusMm and that the axis is world-space. It says nothing about turns limits, the required 'revision' string, 'intent', 'handedness', or 'radialDirection', leaving five parameters undocumented.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource ('Create a ... native helix'), plus two distinguishing qualifiers: constant-radius and world-space axis. It clearly separates this from the other curve-creation siblings (circle, arc, ellipse, polyline). It stops short of naming a sibling or stating what it does not do, so it lands at a solid 4.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this tool versus the many alternative curve creators, nor any prerequisite (e.g., does a helix need a workplane or an existing axis?). The agent must infer context entirely from the tool name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.