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

Annotations already establish that this is a safe, read-only, idempotent, non-destructive, closed-world operation. The description adds useful context about returned data components, but it does not describe output structure, pagination, or other behavioral details beyond those annotations.

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 compact sentence that front-loads the core resource and then lists the included data. It contains no filler or redundant explanation.

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 zero-parameter, read-only metadata tool, the description covers the key contents an agent needs to decide whether to call it. It is slightly incomplete because it does not specify the exact return shape or whether the result is a list, object, or grouped structure.

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?

The tool has zero parameters, so there is no parameter semantics to document. The schema is effectively self-explanatory, and the description does not need to compensate for any missing parameter coverage.

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 names a specific resource, Tokyo wards, and enumerates the data included: facility counts, feature tags, data date, and usage rules. It is clear what the tool returns, though it does not explicitly differentiate itself from sibling tools such as search, fetch, or get_facility.

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?

There is no explicit guidance on when to use this tool versus alternatives. The description implies a metadata-listing purpose but never states when an agent should choose list_wards over search, search_facilities, fetch, or get_facility.

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