store_lookup

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the data is public, cached for a few hours (relevant for freshness/staleness), and 'nothing is saved in the project' (a non-obvious side-effect guarantee). That is real added value.

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, front-loaded with the action and resource, followed by the field enumeration and the caching/persistence caveat. Every clause carries information, though the long comma list of return fields is dense and could be trimmed since an output schema already exists.

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 annotations covering the safety profile and an output schema covering return values, the description only needs to add input semantics and behavior, and it does both. Accepted query formats and the caching/no-persistence behavior are stated; only the precise link/ID format is left implicit.

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 coverage is 0% for the single 'query' parameter, so the description must carry the semantics. It does so by naming the three accepted input forms ('by name, app id or store link'), which the schema does not express. It stops short of giving format examples (e.g., a store-link shape), so it compensates well but not completely.

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 and resource ('Look a game up on the Steam store') and then enumerates the returned data (price, review score, players right now, release date, genres, etc.), which makes the tool's scope unambiguous. It does not, however, name or distinguish itself from any sibling (e.g., preview_store, compare_games, study_market), so it falls short of a 5.

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?

The description implies when the tool is useful by listing the data it returns and noting the accepted input forms ('by name, app id or store link'), but it gives no explicit when-to-use/when-not guidance and never routes the agent to an alternative tool. Usage is inferable rather than stated.

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