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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds real value beyond them: 'Computed server-side, nothing stored' discloses the privacy/no-persistence behavior when no data is retained. It stops short of describing pagination or error behavior, but for a stateless estimator this is solid context.

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?

Four tight sentences with no filler; the core function is front-loaded and the estimate caveat follows immediately. Every sentence earns its place.

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 helpfully explains the return values (US/UK/EU dress sizes and letter sizes) and the store-chart link. However, for an 11-parameter tool it leaves the measurement and gender parameters unexplained, so it is only partially complete for the tool's complexity.

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 carry the parameter burden. It names only height, weight, and body_type out of 11 params, omitting required 'gender' and the units/waist/bust/hip/chest/measurement-unit fields entirely, leaving most inputs undocumented.

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 (Estimate) and resource (clothing sizes) and names the core inputs. It is clearly distinguishable from siblings like outfit_tryon, photo_tryon, and shop_search, none of which estimate sizes.

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?

It sets expectation with 'An estimate only; always check the store's own chart,' which implies this is a preliminary lookup, but it never states when to choose it over photo_tryon or any sibling. Usage is implied rather than explicit.

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