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

Annotations only declare readOnlyHint and openWorldHint, while the description adds substantive behavior: each registry's status, version date, source, matches, and what was not checked are returned. It also warns that a domain alone stays unverified, that results are limited to stated scope and dates, and that no match is not proof none exists; these are meaningful limits beyond the 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 front-loads the multi-registry scope and then groups caveats into short clauses. It is dense but purposeful; most wording earns its place, though it could be slightly tighter.

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?

For a complex 10-parameter, multi-registry screening tool with an output schema, the description names covered registries, summarizes returned fields, states limitations, routes single-registry queries elsewhere, and includes a compliance disclaimer. With annotations and schema carrying the safety and parameter detail, this is complete enough for an agent to call it correctly.

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 the schema already documents all 10 parameters and the baseline is 3. The description reinforces the domain caveat by saying a domain alone stays unverified, but it does not add syntax, constraints, or meanings beyond what the schema already provides.

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 first sentence names the resource set (Japanese registries including FSA, MOF, EDINET, ISA, CAA, and gBizINFO) and the operation (checks across several registries). It also distinguishes multi-registry checks from single-registry tools, so an agent can identify this as a cross-registry public-record status check.

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 to use this for checks across several registries and to use jp-finance, jp-sanctions, jp-edinet, or jp-ssw-support-orgs for one registry. It also states important scope limits such as no match not proving absence and no compliance determination, though it does not mention the sibling entity_evidence_batch or explain when bulk processing is appropriate.

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