create_primitive

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full behavioral burden. It discloses that rotation is in degrees, sizes are in Blender units, and that primitive-specific options are ignored for incompatible primitives. It also states the return value (full record). This goes beyond the schema and gives the agent essential behavioral expectations, though it doesn't detail side effects like collection creation (though that is in the schema).

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 three concise sentences, front-loaded with the primary purpose. It packs essential behavioral details without redundancy. Every sentence contributes to understanding how to use the tool correctly, with no wasted words.

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 tool with 14 parameters and no output schema, the description covers key behaviors: it returns the full record, explains units, and clarifies parameter applicability. It does not cover every parameter detail, but the schema descriptions handle most (86%). It lacks explicit mention of side effects like collection creation, but that is documented in the schema. Overall, it provides sufficient context for an agent to use the tool correctly.

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 coverage is high at 86%, so baseline is 3. The description adds meaningful semantics by clarifying units (Blender units) for size/depth/radius, which are not fully specified in the schema (radius has no description), and by explaining that primitive-specific options are ignored when not applicable. This adds value beyond the schema, justifying a 4.

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 the tool adds a primitive mesh object to the scene, with a specific verb and resource. It does not explicitly differentiate from sibling tools like create_cube, but the general nature is evident. The mention of rotation, sizes, and return value adds specificity, though it doesn't distinguish from alternatives.

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 provides clear guidance on parameter units (degrees, Blender units) and that primitive-specific options are ignored by primitives lacking them, which is useful for parameter usage. However, it does not mention when to use this tool versus alternatives like create_cube or create_empty, nor any exclusions or conditions for use.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.