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

Annotations already declare readOnlyHint, non-destructive and closed-world, so safety is covered. The description adds genuinely new behavioral context: the catalog is what the factory 'accepts today' (i.e. volatile), and the returned ids must be consumed verbatim rather than constructed. It stops short of describing the response shape or any pagination, though with no output schema that is a modest gap.

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?

Two sentences, no padding, and the dependency on quote_avatar is front-loaded in the second sentence before the id constraint. The first sentence is a dense noun list without a verb, which is slightly less scannable than a declarative opening.

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 single-parameter, read-only, closed-world lookup with annotations covering safety, the description supplies what is needed: what is listed, that ids are opaque values from the response, and where this fits in the workflow. Only the response structure is unaddressed, which is acceptable but not fully covered given there is no 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?

There is a single optional parameter (language) whose schema description is fully documented, including that replies and prices follow it. The description adds no meaning beyond the schema, so the 100%-coverage baseline of 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?

The description enumerates the resource precisely — visual styles, states/movements (idle, talking, waving), resolutions and qualities — so an agent knows exactly what catalog this returns. It lacks an explicit verb and does not distinguish itself from the similarly named list_actions and list_categories siblings, which could surface overlapping-looking items.

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?

It gives a clear ordering rule ('Call before quote_avatar') and a hard constraint ('pass the ids exactly as returned; never invent a style'), which is strong when-to-use guidance plus an exclusion. It does not say when list_actions or list_categories would be the correct sibling instead, so alternatives remain partially inferred.

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