add_full_round

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

With no annotations, the description carries the full behavioral burden. It adds real geometric behavior context (the round runs across the rib, not along it; radius is half the side distance; result contains width_mm), which is valuable. But it never states that this is a model-mutating operation, nor covers failure conditions or permissions, leaving the mutation nature undisclosed.

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, front-loaded with the purpose, then selection rules, then the result/area formula. Dense but each sentence earns its place; the hand-calculation formula is a small extra but aids the geometry mental model.

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?

There is no output schema, so the description's hint that the result contains width_mm is a useful partial return description. However, for a mutation tool with 0% schema coverage and no annotations, it omits whether the model is modified, the effect on existing geometry, and the meaning of the `name` parameter.

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%, so the description must compensate, and it does for most parameters: it defines what `face` denotes (the top face), how the two side faces are selected, and that (x, y, z) is a point the top face passes through. Only the optional `name` parameter goes unexplained, which is a minor gap.

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 gives a specific verb and resource: "Round a rib's top off completely: a full round fillet, as on a moulded part." This is clearly distinguished from a generic fillet by being scoped to a rib top and to a full-round profile. It does not, however, explicitly name sibling tools like add_fillet or add_chamfer to disambiguate the choice.

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 geometry selection (which face is the top, which are the sides) but never states when to use this versus add_fillet, add_chamfer, or other rounding tools, nor any prerequisites or exclusions. Usage must be inferred from the geometry narrative.

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