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

With no annotations, the description carries the full burden and does disclose the most consequential trait: 'Bills the API key owner's plan quota / credits', so an agent knows calls cost money. It also explains derived output fields (site_type categories, weak-site checks). It omits pagination/truncation behavior and what happens when the area is too broad or the quota is exhausted.

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?

Three tight sentences, front-loaded with purpose, then the return payload, then the filtering trick and cost note. The long field enumeration earns its space because no output schema exists.

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?

Because there is no output schema, the description must describe results and does so thoroughly, including cost implications — the two things an agent most needs here. Remaining gaps are pagination/limit interaction and failure modes, which are secondary for 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?

Schema description coverage is 100%, so parameters like area granularity and the 'small' ordering are already documented in the schema. The description adds no further parameter-level detail (e.g. default limit values or valid industry keyword syntax), so the 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 and resource ('Generate a sales list of local businesses') plus the exact scope ('industry × area in Japan'), which no sibling shares. The returned fields are enumerated, so an agent knows precisely what it gets back.

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?

Gives actionable in-task guidance: 'Use site_type != "own" to find shops without their own website', which tells the agent how to reach a common sub-goal from the output. It stops short of explicit when-not-to-use or alternatives — the only sibling, get_account, is unrelated, so the omission is minor.

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