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

Annotations already cover readOnly, idempotent and openWorld, and the description adds genuine behavioral context beyond them: candidates are labelled exact_name vs fuzzy_candidate, results include total and may be truncated, the gBizINFO source notice is carried, and results are 'not official'. It stops short of stating rate limits or pagination mechanics.

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: purpose first, then result behaviour, then the disclaimer. The leading question is slightly rhetorical but effectively front-loads the purpose, and nothing is wasted.

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 a full output schema, complete parameter descriptions and read-only/idempotent annotations, the description only needs to add matching semantics, no-auto-pick behaviour and the non-official caveat — all of which it does. A brief note on how to proceed after choosing a candidate would make it fully complete.

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 name, limit, prefecture and address_hint are already fully documented in the schema, including the partial-match and no-drop ordering semantics. The description restates the name/prefecture behaviour but adds no parameter meaning beyond the schema, 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?

The description opens with a specific verb+resource question ('Which Japanese corporate numbers could this company name refer to?') and then states exactly what it searches (gBizINFO by partial name, optional prefecture) and what it returns (every candidate marked exact_name or fuzzy_candidate). This clearly separates it from siblings like gbizinfo_company_basic, which presumably takes an already-known number.

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?

It makes the use case explicit: name-based resolution with no automatic selection ('Never picks one for you'), which is the condition that selects this tool over a direct number lookup. It does not, however, name the alternative tool (e.g. gbizinfo_company_basic) to call once a number is chosen, so the routing guidance stops one step short of 5.

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