jcrew_size_chart

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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it delivers. It explains the subset behavior of measurements depending on style/category, the dual inches/centimeters output, and crucially the zero-value quirk: 'A measurement value of 0 means that column doesn't apply to this style... the upstream itself doesn't distinguish that from a genuine zero, so this endpoint passes it through as-is.' This kind of edge-case disclosure is exactly the behavioral context an agent cannot infer from the schema.

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 description is front-loaded with the core action and every sentence earns its place: return content, measurement subsets, pid provenance, site constraint/default, and the zero-value caveat. No fluff, no redundant restatement of the tool name, and the length is proportionate to the tool's complexity.

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 two-parameter lookup tool with no annotations and no output schema, the description covers nearly everything: what the return contains, units, per-category variation, the zero semantics, and both parameter meanings. The only gaps are error behavior (e.g., what happens on an invalid pid or a site mismatch) and the exact response shape (how sizes are labeled/structured), which remains slightly underspecified without an output schema.

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 the baseline is 3, but the description adds meaningful value beyond the schema. It names the precise provenance of pid ('as returned by jcrew-search's products[].id field') and discloses the site default ('default jcrew') plus the constraint that site must match the pid's storefront. These additions help an agent construct valid calls.

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 opens with a specific verb+resource: 'Get the size chart for a J.Crew or J.Crew Factory product.' It then details what is returned (real body measurements per size, in inches and centimeters), which makes the tool's function unmistakable. It is clearly differentiated from sibling tools like jcrew_product and jcrew_product_reviews by focusing exclusively on body measurements and size charts.

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 provides strong usage context: pid must come from jcrew-search's products[].id field, and site must match the storefront the pid belongs to, with a default of jcrew. This tells the agent when this tool is appropriate (after a search has yielded a pid). However, it does not explicitly name alternatives or state when not to use this tool versus jcrew_product, so it stops short of a 5.

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