add_gear

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

With no annotations, the description carries the full burden and does well: it enumerates the returned fields ({handle, name, volume, pitch_radius, tip_radius, root_radius, ...}), states the external/internal distinction, and gives the meshing/phase advice needed to avoid tooth interference. It does not explicitly state that this mutates document state or note any permissions, which keeps it short of a 5.

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?

Front-loaded with the core purpose, then parameters, return shape, and finally the meshing tip – a logical ordering with no wasted preamble. The density is high but most sentences earn their place, though the return-shape block is somewhat terse.

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?

With no output schema and no annotations, the description compensates by inlining the return structure and the meshing relationship, plus per-parameter meaning. It is nearly complete; only an explicit note on document-mutation side effects or prerequisites would round it out.

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 0% (all parameters have titles only), so the description must compensate and it does for every parameter: teeth (count, >= 3), module (mm, pitch diameter = module * teeth), height (extrusion thickness mm), pressure_angle (deg, default 20), external (True external / False ring profile), and placement ([x, y, z] mm translation). This is exactly the missing semantic layer the schema lacks.

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 ('Add') and resource ('involute spur gear'), and clarifies the implementation ('FreeCAD's core involute generator') plus the output form ('extruded to a solid'). An agent can immediately distinguish this from sibling gear-adjacent tools like add_rack, add_sprocket, and add_pulley.

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 meshing geometry (axes spaced pitch_radius_a + pitch_radius_b, phase by half a tooth), which is useful context, but it never states when to choose this tool over alternatives such as add_rack or add_sprocket. Usage is implied by the gear-type phrasing rather than explicitly guided.

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