Create a cone or frustum by revolving a trapezoidal profile 360°, returning mass properties. Use after new_part for parametric part modeling.
Create a cone/frustum by revolving a trapezoidal profile 360°.
top_diameter_mm = 0 gives a full cone. Returns mass properties (volume = π·h/3 · (rb² + rb·rt + rt²)). Use new_part first.
| Name | Required | Description | Default |
|---|---|---|---|
| name | No | Revolve | |
| height_mm | Yes | ||
| top_diameter_mm | Yes | ||
| bottom_diameter_mm | Yes |
Changes observed during successful MCP inspections.
v0.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations, so the description must carry the behavioral burden. It discloses the construction method, the special full-cone case, and that the tool returns mass properties with a volume formula. It omits placement/orientation and failure behavior, but the core behavioral profile is clear.
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: the main action appears first, followed by the key parameter case, return value, and prerequisite. Every sentence adds useful information with no filler or redundancy.
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?
Given no annotations, no output schema, and no schema-level parameter descriptions, the description covers the essential call context: what the tool creates, when the shape is a cone vs. frustum, what it returns, and the need for a new part. It could add placement/orientation and numeric validity constraints, but an agent can likely invoke it correctly as written.
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 compensate. It does so by explaining top_diameter_mm = 0 and giving a volume formula that ties height, bottom radius, and top radius together. The optional name parameter and the rb/rt notation are not detailed, but the required geometry is interpretable.
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: it creates a cone/frustum by revolving a trapezoidal profile 360°. This directly distinguishes it from sibling tools like add_cylinder, add_disc, and add_revolved_profile.
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?
It gives an explicit prerequisite ('Use new_part first') and clarifies the cone vs. frustum distinction via top_diameter_mm = 0. It does not explicitly name sibling alternatives or say when to prefer add_cylinder, so it stops short of full routing guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.