住所の位置(ポリゴン/ポイント)を取得

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

With no annotations provided, the description carries the full burden and does so excellently. It discloses that the tool fetches TTL and converts to GeoJSON client-side to reduce server load, auto-completes omitted county/city names and variant characters, uses centroid fallback when LOD lacks representative points (with point_source property), returns RFC 7946 GeoJSON compatible with mapping libraries, and explains simplify/dropSmallIslands side effects. This goes far beyond a basic action statement.

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 long but every sentence delivers actionable information. It is front-loaded with the core purpose, then systematically covers conversion, auto-completion, centroid fallback, GeoJSON compatibility, alternative tools, and parameter usage nuances. There is no redundancy or filler; despite its length, it remains efficiently organized and directly relevant to tool selection and invocation.

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 the tool's complexity—three parameters with nuanced behavior, no output schema, and no annotations—the description is remarkably complete. It explains the return format (GeoJSON Feature), the point_source marker for centroids, how to use with mapping libraries, limitations (e.g., banchi points only, no building numbers), and when to use sibling tools. It leaves no practical gaps for an agent deciding whether and how to call this 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?

Even though schema coverage is 100%, the description adds substantial meaning beyond the schema. For 'address' it explains levels (prefecture to chome polygon, banchi point, gou not possible), URI example, and auto-completion. For 'simplify' it provides concrete point counts for different administrative levels and warns against 'high' as default. For 'dropSmallIslands' it explains the area threshold, applicability only to prefectures, and rationale. These details are not in the schema descriptions.

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 opens with a specific verb and resource: '住所LODから、指定した住所のポリゴンまたはポイントをGeoJSON Featureとして取得する' (retrieves polygon or point for a specified address from Address LOD as a GeoJSON Feature). It clearly distinguishes from sibling get_address_locations by explicitly stating that for multiple addresses, one should use get_address_locations instead of calling this tool multiple times.

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 provides explicit guidance on when to use this tool vs alternatives: for single addresses use this, for multiple use get_address_locations. It also gives detailed usage conditions for parameters: simplify recommended at city/prefecture levels with specific point counts, dropSmallIslands only for prefectures, and 'high' simplify as a last resort. These are clear when/when-not and alternative recommendations.

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