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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-source traits are covered. The description adds genuinely new context beyond that: rows come back in page order, each row carries session, announcement date, consistency check, page URL and retrieved_at, and status is 'unknown' when a page was not or could not be read. The only gap is that it does not state pagination behavior beyond the limit cap.

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?

It is front-loaded with the core question the tool answers and the alternative-tool routing comes last. It is efficient, though enumerating the returned column names overlaps with the existing output schema and could be trimmed.

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 an output schema covering return values and annotations covering the read-only, open-world profile, the description only needs scope and routing, both of which it supplies, plus the useful 'unknown status' caveat. It stops short of explaining list size or refresh cadence, which leaves a small gap for a listing 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?

There is a single parameter, limit, and the schema already documents it fully (1-100, default 50) at 100% coverage. The description adds no meaning about how the limit interacts with page order or whether exceeding available exams truncates silently, 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 states a specific verb and resource (list national exams on MHLW's current pass announcement list) plus the payload (examinees, passers, pass rate, all candidates) and the row granularity (one row per exam in page order). It also names the sibling exam_results_lookup as the tool for a different scope, so an agent can distinguish the two without opening either schema.

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 explicitly routes the agent: use this tool for the current announcement list, and use exam_results_lookup for new graduates, revisions and earlier sessions. That is both a when-to-use and a when-not-to-use statement naming the alternative.

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