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

Annotations already declare readOnlyHint and openWorldHint. The description adds a genuine behavioral constraint beyond them: listings 'only ever contains that seller's ACTIVE listings,' which prevents an agent from expecting sold/inactive items. It stops short of describing pagination or response shape.

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 front-loaded sentences with no wasted framing: the return contents come first, then the parameter clarification. Slightly dense with parenthetical asides but appropriately sized.

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?

An output schema exists so return-value detail is not required. The description covers what the tool returns and where the key input comes from, which is sufficient for a read-only lookup; only pagination semantics for page/limit are missing.

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 0%, so the description must carry the load. It explains username well (a Grailed username sourced from a listing's seller.username field), but page and limit are entirely undocumented here or in the schema, leaving a real gap on two of three parameters.

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 resource: a Grailed seller's public profile plus a page of active listings, and frames it as Grailed's own 'shop' view. Clear enough to distinguish from grailed_seller_reviews without opening a schema, though it does not explicitly name the sibling it differs from.

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?

Adds a useful sourcing hint (username comes from a listing's seller.username field) and clarifies the listings are active-only, which implies when to use it. However, it never states when to prefer this over alternatives like grailed_seller_reviews or grailed_search, so usage is only implied.

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