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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds meaningful context beyond them: data comes from Fledly's own store rather than the live App Store, and revenue/chart/review-alert fields are only populated 'when Fledly tracks it', which tells the agent to expect partial results.

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 front-loaded sentence with the lookup key stated first and the returned payload after the colon. The trailing field list is dense but each item earns its place by telling the agent what it can retrieve; only the 'when Fledly tracks it' qualifier placement is slightly awkward.

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 no output schema, the description compensates by enumerating the return payload, and it flags the tracking-dependent fields. For a 2-parameter read lookup, the only real omissions are not-found behavior and country scoping, which are minor.

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 100%, so both parameters are already documented, and the description's mention of 'App Store id, apps.apple.com link or name' largely restates the schema. The country parameter and its default are never mentioned, so no meaning is added beyond the structured fields.

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 ('looks up one iOS app in Fledly's data') and enumerates the fields returned (metadata, ratings, price, dates, chart ranks, revenue, review alerts). The emphasis on 'one' implicitly separates it from search_app_store and get_top_charts, though no sibling is named outright.

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 accepted identifier forms (id, link, name) suggest it is the single-app lookup, but there is no explicit statement of when to prefer it over search_app_store or get_my_apps, and no 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.