Create a cone primitive in Rhino by defining base center, radius, and height. Use it to add conical geometry to the active model or a specified document.
Add a cone primitive (bridge required for non-Z axes).
| Name | Required | Description | Default |
|---|---|---|---|
| args | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only indicate readOnlyHint false, so the description carries some burden. 'Add a cone primitive' implies a document-mutating creation operation, and the non-Z-axis bridge requirement is a behavioral constraint beyond the annotation. Still, it leaves important behavior unexplained, such as the default orientation, return value, or error conditions.
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 extremely concise and front-loaded, with no filler words. The caveat about non-Z axes is packed into a short parenthetical, but its brevity borders on cryptic, reducing clarity for an agent unfamiliar with the bridge concept.
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?
Although an output schema exists, the description leaves major gaps: it does not state the default cone axis, how to orient a cone along non-Z axes, what 'bridge' refers to, or how the layers/name/doc_id arguments behave. For a tool with a nested input schema and many sibling primitive tools, this is not enough context for an agent to reliably select and invoke it.
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% for the core parameters, and the description does not compensate by explaining base_center, radius, or height. While those names are somewhat self-explanatory, the description provides no additional meaning about orientation, units, or how the parameters interact; the 'non-Z axes' hint is the only oblique reference.
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 clearly states a specific action and resource: 'Add a cone primitive'. This distinguishes it as a primitive-creation tool, though it does not explicitly differentiate it from sibling cone-related tools like rhino_cmd_cone, rhino_truncated_cone, or rhino_subd_cone.
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 parenthetical 'bridge required for non-Z axes' gives a conditional usage constraint, which is useful guidance for when this tool might not be directly applicable. However, it does not explain what 'bridge' means, nor does it specify when to use this over other cone-creation siblings or provide explicit exclusions/alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.