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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds real value by disclosing a 30-minute cache and the ordering of returned skins (price descending), which are behavioral traits an agent could not infer from annotations or 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 definition is front-loaded with the core resource, then returns details, a cross-reference, and caching. The field enumeration is dense but productive. It is appropriately sized, with no filler, though the embedded field list is slightly run-on.

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?

No output schema exists, so the description correctly carries the return-shape burden: it names the collection fields, defines `released`, and specifies the skin object shape and ordering. Combined with annotations covering safety and a fully specified slug parameter, this is nearly complete, lacking only edge-case behavior such as invalid slugs.

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?

There is only one parameter and the schema description coverage is 100%, with the slug format and example already fully documented. The description adds no additional parameter semantics, so baseline 3 is appropriate for a high-coverage single-param schema.

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 identifies a specific resource — one collection plus all its member skins — and lists the returned fields, making the purpose concrete. It implicitly distinguishes itself from the sibling list_skin_collections by being singular, but it does not explicitly name that sibling or state verb+resource in the first sentence.

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 tool fetches a collection by slug. The description does point out that value-over-time lives at GET /market/collection-value, which is useful routing, but it never says when to choose this over list_skin_collections or get_skin. No explicit exclusions or prerequisites are given.

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