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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description adds real value by disclosing the plan-gated behavior: three screenshots without Library Pro, with additional content and other countries behind a $19/month tier. It also describes the return composition, though it does not cover auth or rate limits.

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 and compact: the first sentence describes what is returned, and the second covers plan limitations. 'The rest' is slightly ambiguous, and the first sentence is dense, but no sentence is wasted.

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?

There is no output schema, so the description must explain return values, and it does: metadata, ordered screenshots, posters, event photos, related apps, and create_restyle arguments. It also explains the plan gating, leaving only minor gaps around identifier requirements and fallback behavior, which the parameter schema largely covers.

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%, and each parameter already has a clear description, so the baseline is 3. The tool description does not add syntax, selection logic, or fallback behavior beyond saying it retrieves 'one directory app'.

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 states a specific verb and resource ('Get one directory app') and enumerates exactly what comes back: metadata, screenshots, posters, in-app event photos, related apps, and create_restyle arguments. This clearly distinguishes it from sibling list or screenshot-only tools without needing to name them.

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 that this tool is for retrieving a single app, but it does not explicitly say when to use it instead of list_directory_apps or get_directory_screens. It also gives plan-gating context but no guidance on choosing among slug, query, or app_id inputs.

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