fusion_sphere

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

Annotations indicate readOnlyHint=false and openWorldHint=true. The description adds value by stating 'Auto-creates a document if none is open', which is a behavioral trait not fully captured in annotations. However, it does not clarify behavior when both radius and diameter are provided or if name is omitted.

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 concise sentences that front-load the core action and key constraints. No redundant information.

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 simple shape creation tool, the description covers the core function, parameter alternatives, units, and a notable side effect. However, it could clarify that radius or diameter is expected (since no parameters are required in schema) and what happens to existing geometry.

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?

With 0% schema description coverage, the description compensates by explaining 'radius OR diameter' and units ('mm'), but does not mention the 'name' parameter or clarify parameter constraints.

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 action ('Create a sphere'), the specific parameters ('radius OR diameter'), units ('mm'), and placement ('centered on the origin'). This distinguishes it from sibling tools like fusion_box or fusion_cylinder.

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 implies usage for creating spheres and mentions auto-creating a document, but does not explicitly state when to use this tool versus alternatives like fusion_cylinder or when not to use it.

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