Geocode a Japanese Address

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds useful context about the official GSI geocoder and its relationship to official_hazard_maps, providing extra behavioral framing without contradicting 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 two sentences, front-loaded with the core action, and provides sibling context without unnecessary fluff. Every clause contributes to understanding the tool's purpose and usage.

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?

The tool is simple with a single parameter, no output schema, and meaningful annotations. The description covers the main purpose, the external geocoder, and the scenario for direct use. It does not mention output format details, but for a simple geocoding tool this is acceptable.

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% as the 'address' parameter includes its own description. The tool description repeats the parameter's purpose without adding extra semantic detail like formatting or examples. However, it does clarify that the address must be Japanese, which is slightly beyond the schema.

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 specific verb 'Convert' with the resource 'a Japanese address' and the output (coordinates and prefecture/municipality). It also distinguishes from siblings by noting it's a utility used by official_hazard_maps, making its role unambiguous.

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 says 'call it directly when you only need coordinates', which indicates when to use this tool versus relying on official_hazard_maps. It also implies that official_hazard_maps is the higher-level alternative.

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