Shell Body

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

Annotations declare a non-destructive, non-idempotent mutation, so the safety profile is covered. The description adds valuable context beyond annotations: the return values ('faces_removed and removed_face_z') and a global units clarification (cm and degrees), which are important behavioral details for correct invocation.

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 sentences with a clear structure: purpose first, then face-selection semantics, then return values and units. Every sentence is informative and front-loaded, with no redundancy.

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 six-parameter mutation tool with no output schema and zero schema descriptions, the description covers the most complex aspects (face selection, units, returns) well. The main gap is the lack of any mention of body selection parameters (body_name, body_index) or the thickness parameter, though the latter is required and its name is largely self-explanatory.

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 carry the burden. It successfully clarifies the face_selection enum values and the role of z_min/z_max, but it says nothing about thickness, body_name, or body_index, leaving three of six parameters undocumented anywhere.

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 states a specific verb ('Hollow out') and resource ('a body'), and clarifies the mechanism ('removing the selected planar face(s) as the opening'), which distinguishes it from other body-modifying siblings like fillet or chamfer.

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 explains the face selection options (top/bottom/up_facing/down_facing) and the optional z_min/z_max limits, which is useful for using the tool correctly. However, it doesn't specify when to use shell vs alternatives like offset_faces or thicken_surface, nor does it state prerequisites such as needing a solid body.

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