f360_draw_circle

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

With no annotations, the description carries the full burden; it does disclose the non-obvious constraint that the circle is always at the origin (no position parameters exist) and that a sketch must pre-exist. It does not say what happens on failure (no active sketch, invalid diameter), whether the operation is undoable, or what is returned.

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?

Three short sentences, front-loaded with the operation and its scope, followed by the prerequisite and use cases. The trailing 'Diameter in millimeters' sentence slightly duplicates the schema but is cheap.

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 one-parameter creation tool with no output schema and no annotations, the description covers the essential call preconditions (active sketch, units) and geometry. Only error behavior and return value are unaddressed, which is a minor gap at this complexity.

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 100% and the single parameter is fully documented in the schema. The description's 'Diameter in millimeters' merely restates the schema's unit, adding no new semantics such as valid ranges or how diameter relates to the fixed origin center.

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?

States a specific verb (Draws) and resource (a circle) with the key geometric constraint that it is centered at the origin in the active sketch. This distinguishes it cleanly from sibling f360_draw_rectangle and from f360_hole.

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?

Gives an explicit prerequisite (f360_create_sketch must be called first) and lists intended use cases (shafts, bosses, through-holes, pads). It stops short of naming alternatives — e.g., that f360_hole is preferable for true through-holes — so an agent must infer that routing.

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