Geocode (Japanese address -> lat/lon candidates)

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

With no annotations, the description carries the full burden of behavioral disclosure. It usefully reveals that partial matches are allowed, returns up to 10 candidates, and uses the ReverseGeoJP API. However, it does not mention error handling, rate limits, or the read-only nature, which are relevant but perhaps less critical for a simple lookup tool.

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 purpose and includes key limitations (partial match, max 10). Every word adds value, and there is no redundant information.

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 single-parameter tool with no output schema, the description adequately explains the return value: town district and lat/lon candidates, capped at 10. It could be more complete by mentioning coordinate format or failure behavior, but it covers the essential information needed to understand the tool's function.

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 schema already describes the sole parameter 'address' as '検索する住所文字列' (address string to search), so the baseline is 3. The description adds meaningful semantics by specifying that the address must be a Japanese string and supports partial matching, which goes beyond the generic schema description.

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's function: converting a Japanese address string into candidate town districts (町丁目) with latitude/longitude, returning up to 10 results. It uses a specific verb '返します' (returns) and distinguishes from reverse_geocode by explicitly indicating direction from address to coordinates.

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 does not provide any guidance on when to use this tool versus alternatives like reverse_geocode or lookup_location. It merely states what the tool does, leaving the agent to infer the appropriate context from the directionality implied by the name and title.

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