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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description adds the valuable extras: units in cm, the exact measurements returned, and a consistency guarantee that the chart and rule match the product page. It does not say what happens when no body measurements are given (chart only?) or how fit changes the recommendation, leaving some behavioral gaps.

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?

A single dense sentence with the output content front-loaded and the conditional pick logic following. No filler, though the parenthetical "(and height)" is slightly compressed to the point of ambiguity about whether height is optional in the pick.

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 usefully characterizes the return (chart with half-chest and length, plus conditional size recommendation). Given six parameters and a low schema coverage, the omission of how fit and lang affect results is a real but secondary gap for a read-only lookup tool.

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 only 17%, so the description must carry meaning and it partially does, tying chest_cm/height_cm and shoe_eu to the size-pick behavior. It says nothing about fit (fitted/regular/oversized), lang, or slug, so several parameters remain semantically 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 concrete resource (the product's real size chart in cm, with garment half-chest and length) plus a second capability (a size pick from shopper measurements). The phrase "same chart and rule as the product page" implicitly tells the agent this is the authoritative sizing source rather than get_product, though it never names a sibling explicitly.

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?

Usage is implied conditionally: the chart is always returned, and a size pick appears only when chest (and height) or EU shoe size are supplied. There is no explicit when-to-use versus alternatives, no statement of when-not to call it, and no note that slug must identify an existing product.

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