Similar apps

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered elsewhere. The description's real contribution is stating that one of `id` or `appId` must be supplied, which is non-obvious because the schema lists no required parameters. It says nothing about rate limits, coverage per country, or empty results, so it is modest rather than rich.

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 short sentences, with the resource definition front-loaded and the invocation constraint immediately after. Nothing is wasted and there is no filler.

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 simple read-only lookup with five fully documented parameters and no output schema, the description plus schema covers essentially everything. The remaining gap is edge behavior (both identifiers supplied, no similar apps found), which is minor for a tool of this complexity.

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 per-parameter meaning is already fully documented, and the baseline of 3 applies. The description adds only the mutual-exclusivity/at-least-one rule for `id` vs `appId`, which the schema does not express via `required`; it adds nothing about `lang`, `country`, or `verbose`.

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: retrieve the 'customers also bought' / similar apps shown on an app's page. That is unambiguous and distinct from app_details or search_apps. It does not explicitly name how it differs from siblings, so it lands just 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?

Usage is implied by the resource itself (call it when you want related apps), and the constraint 'Provide either `id` or `appId`' gives a concrete invocation rule. There is no explicit when-not guidance, no mention of app_details as the tool for the app's own metadata, and no note on behavior when the app has no similar apps.

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