make_datum_planeCreate a datum plane in a body at an offset from a base plane or a selected face.
Create a Datum Plane in a Body.
base: 'XY' | 'XZ' | 'YZ' for body origin planes. Pass a face_tag dict {handle, tag} for attachment to a face on another shape. offset: shift along the plane normal in mm.
| Name | Required | Description | Default |
|---|---|---|---|
| base | No | XY | |
| body | Yes | ||
| name | No | DatumPlane | |
| offset | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description is consistent with the annotations: readOnlyHint=false and destructiveHint=false align with 'Create.' It adds useful context beyond annotations by describing face-tag attachment and offset direction/units. It does not disclose side effects, return values, or behavior around duplicate names, so transparency is partial.
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?
The description is compact and front-loaded, with no filler. The core operation appears first, followed by concise parameter-level guidance for base and offset.
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 mutating tool with no output schema and 0% schema description coverage, this description is not complete enough. It omits the meaning of the required body parameter and the name parameter, and it doesn't specify the exact face_tag dict structure or what the tool returns. The schema-type mismatch further reduces confidence in correct invocation.
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%, so the description must carry parameter semantics. It does explain base choices, face attachment, and offset units, but it leaves body and name undocumented. It also conflicts with the schema by telling the agent to pass a face_tag dict for base when base is typed as a string, which could mislead invocation.
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 opens with a clear verb and resource: 'Create a Datum Plane in a Body.' This unambiguously states what the tool does and is distinct from sibling creation tools like make_sketch or add_primitive. It doesn't explicitly contrast it with related tools, so it stops short of a top score.
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?
The description explains the two base modes (origin planes and face attachment) and the offset behavior, which gives usable invocation guidance. However, it doesn't explicitly state when to prefer this tool over alternatives or mention prerequisites. Usage guidance is implied rather than explicitly scoped.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.