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 usefully discloses one runtime behavior — lat/lng are null when coordinates are unresolved — which is exactly the kind of surprise an agent needs. It says nothing about permissions/auth, what happens for an unknown slug, or whether the AI 設計提案 field is costly to compute.

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?

Two compact sentences with zero filler: the returned content first, the null-coordinate caveat second. Nothing is repeated and nothing is buried.

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?

With no output schema, the description does the right thing by enumerating the returned fields and flagging the nullable pair. For a single-parameter read tool this is close to sufficient; only auth/error behavior is missing.

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% and the single parameter's description already points to list_land_listings for obtaining a slug. The description only restates 「slug を指定して」, adding no format or sourcing detail beyond the schema, so baseline 3 applies.

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?

States a specific verb (取得) and resource (1件の売地の詳細) and enumerates the content returned (価格・面積・用途地域・AI 設計提案・座標). It doesn't name list_land_listings as the sibling it complements, but the singular-vs-list distinction is clear from the text.

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 phrase 「slug を指定して 1 件」 implies this is the single-record lookup, but the description never states when to use it instead of list_land_listings or probe_land. Routing to the listing tool appears only in the schema's parameter description, not in the tool description itself.

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