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

No annotations are provided, so the description carries the full burden. It indicates a read-only operation (returning a list) but does not disclose any behavioral traits such as caching, real-time-ness, authentication, or rate limits. For a simple list tool this is minimally adequate.

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 description is a single efficient sentence in Japanese, front-loading the core action and user. Every word adds value, with no redundancy.

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?

Given no parameters and no output schema, the description provides sufficient context: it names the tool's purpose and target users. It omits output structure details, but '一覧' implies a list, which is acceptable for a simple tool.

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?

There are zero parameters, and the input schema has 100% coverage with no descriptive fields. Following the baseline guidance for 0 params, a score of 4 is appropriate since the description has no parameters to add meaning to.

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 clearly states the tool returns a list of apps currently recruiting testers, using a specific verb ('返す' - return) and resource ('アプリ一覧' - app list). It differentiates from siblings 'get_service_info' and 'how_to_get_testers' by focusing on active listings.

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 explicitly states the tool is for people who want to join as testers to see which apps are available, providing clear context. However, it does not mention when not to use it or contrast with alternatives like the sibling tools.

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