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

No annotations are supplied, so the description carries the full burden. It does disclose provenance (RegBase jp-diff-feed actor) and cadence (daily diff), which implies a read-only, periodically refreshed dataset, but it says nothing about freshness lag, ordering, result volume, or whether credentials are needed.

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 front-loaded sentences with no filler; the resource and scope come first and provenance last. The 'RegBase jp-diff-feed actor' clause is somewhat internal jargon, which keeps it from a 5.

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 should say more about the shape of returned records (fields per company, pagination behavior). It adequately conveys scope and optional filters for a simple three-parameter read tool, but leaves the return contract underspecified.

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%, so all three parameters are already documented, including the change-type enum values. The description's enumeration of change categories loosely mirrors the change_types filter but adds no syntax or format detail beyond the schema; 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: latest changes in Japan's National Tax Agency corporate registry, enumerating the four change categories (new, changed, closed, revived). An agent knows what it returns, but nothing distinguishes it from siblings like lookup_company or get_snapshot_info.

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?

There is no when-to-use guidance and no alternative named. The phrase 'daily diff' implies it is for recent-change monitoring rather than single-company lookup, but the agent must infer this and receives no signal about when lookup_company or get_snapshot_info would be the better choice.

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