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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), and the description adds genuinely useful behavioral detail beyond that: units come back in both inches and centimeters, the returned column set varies by style, and a value of 0 is a sentinel meaning the column does not apply. No auth/rate-limit info, but the sentinel semantics are the kind of edge case an agent would otherwise misread.

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 compact sentences, front-loaded with what is returned before parameter mechanics. Every clause earns its place — no restatement of the name or filler.

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 2-parameter read-only lookup with an output schema present, the definition is complete: it identifies the data, the parameter provenance, the site constraint, and the 0-value edge case. An agent has everything needed to call it correctly after running jcrew_search.

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 carries the burden — and it does: pid is defined as a style id sourced from jcrew_search's id field, and site is constrained to the storefront owning the pid with a default of jcrew. Valid site values are not enumerated, but both parameters gain clear meaning.

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+resource — returns real body measurements per size for a J.Crew/J.Crew Factory product — and enumerates the exact columns (chest, waist, hip, sleeve, length). This distinguishes it from sibling listing/product tools without the agent needing to open a schema.

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?

Establishes the prerequisite flow by stating pid must come from jcrew_search's id field and that site must match the storefront the pid belongs to (default jcrew). Clear context for when this tool is appropriate, though it does not explicitly name what it is an alternative to.

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