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

Annotations already cover read-only, idempotent, non-destructive, and closed-world behavior, so the description's added context is the 'Uncached' note — a meaningful freshness guarantee not expressible in the annotation set. It also discloses the enumerated status values and that price is in USD, beyond what the annotations carry, but says nothing about behavior for an unknown or malformed id.

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 front-loads the resource and its returned fields with no filler. The trailing one-word fragment 'Uncached.' is slightly awkward as a standalone sentence, but it carries real information rather than padding.

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 one-parameter lookup with no output schema, the description usefully substitutes for one by naming the returned fields and the possible status values. The main remaining gap is error/not-found behavior, which matters for a lookup keyed on an id an agent may have guessed or copied incorrectly.

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?

With a single parameter at 100% schema description coverage, the schema already explains the UUID/slug format, pattern, and length limits. The description's repeat of 'by item UUID or slug' adds no constraint or nuance beyond the structured field, so baseline 3 applies.

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 ('Return'), an explicit scope ('one public listing'), and enumerates exactly what comes back: status (available, sold, Available Soon), USD price, and product URL. The singular-item scope cleanly separates it from sibling search_sets, which handles multi-result search.

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 only implied: the 'one listing ... by item UUID or slug' phrasing signals a point lookup on an already-known item rather than a search. No explicit when-to-use/when-not statement or named alternative appears in the description, though the parameter schema does point to search_sets for obtaining ids.

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