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

Annotations cover safety (readOnly, idempotent, non-destructive), and the description goes further by disclosing the output quality ceiling ('rated no higher than Good Match'), a consumer-facing instruction ('tell her so'), and three concrete refusal cases (letter sizes, missing labels, letter-size-only brands) with reasons. That is unusually rich failure-mode disclosure for a read tool.

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?

The most important constraint (no measurements → use this) is front-loaded, and the refusal list is compact. The closing clause 'with the reason' is grammatically tangled with the preceding enumeration, making the refusal sentence slightly harder to parse than the rest.

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, the description carries the return-value burden and does so: it tells the agent the translated size is capped at Good Match, must be communicated to the shopper, and that failures return explanations. An agent can call this and interpret the result correctly without further information.

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%, so all three parameters are already documented at full fidelity, giving a baseline of 3. The description reinforces the from/to relationship and that 'size' is as from_brand labels it, but adds no syntax or format detail beyond the schema's own descriptions and examples.

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 and resource ('translate a band and cup size... into another brand's label') with a concrete example (34DD at Wacoal → Curvy Kate). It also pins the mechanism ('through Measured Size's base size'), which distinguishes it from bra_size_from_measurements and bra_size_at_brand.

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 gate: 'Use this only when the shopper has no measurements; measurements give a better answer,' which routes the agent to bra_size_from_measurements and implicitly scopes out bra_size_at_brand. Nothing about when to select this tool is left to inference.

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