Create a primitive 3D model and generate its STL file and four PNG views, using specified parameters or default settings.
Create a primitive, STL and four PNG views. Prefer model_type and parameters; descriptions only recognize named primitive dimensions. Use get_capabilities for defaults.
| Name | Required | Description | Default |
|---|---|---|---|
| model_type | No | ||
| parameters | No | ||
| description | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does disclose expected outputs (STL and four PNG views) and a limitation of description-based input. However, it omits side effects, permissions, response format, or whether this is a mutating operation beyond the obvious creation act.
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 sentences with no filler and the key usage tip is front-loaded. The only flaw is the slightly ambiguous first sentence, which could be parsed as creating 'a primitive' and 'STL and PNG views' as separate objects.
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?
There is no output schema, so the description must explain outputs; it mentions STL and four PNG views, which helps. It also routes the agent to get_capabilities for defaults. Still, it does not explain what primitives are available, what 'parameters' should contain, or what a successful call returns.
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 adds real meaning by saying that model_type and parameters are preferred, and that description only works for named primitive dimensions. It does not explain the structure of the parameters object or how to reference primitive dimensions, leaving some gap.
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 names a specific verb ('Create') and resource ('primitive, STL and four PNG views'), which says what the tool produces. It also distinguishes itself from the sibling create_model_from_scad by focusing on primitives. Slightly awkward phrasing makes the exact object of creation ambiguous, but the intent is recoverable.
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 gives clear parameter-level guidance: 'Prefer model_type and parameters; descriptions only recognize named primitive dimensions.' It also points the agent to a sibling tool, get_capabilities, for defaults. It does not explicitly contrast with alternatives, but the context for when this tool is appropriate is implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.