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

readOnlyHint is already declared, and the description adds substantial context: the default 365-day window, the market-wide 31-day cap, the coverage boundary for dividend-change detections starting 2026-05-18, and the interpretation rule that a null details.changeFlag means neither an increase nor a cut (share basis undetermined after a split). The one gap is that it does not explain how the maximum limit of 500 is enforced or what happens if more events exist inside the range.

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?

Content is front-loaded with the scope statement, but the full description and caveats are duplicated verbatim in Japanese, roughly doubling length without adding information for an English-reading agent. The opening rhetorical question 'What happened recently?' is decorative rather than informative. Removing the duplication would make it noticeably 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 five-parameter, no-output-schema aggregation tool, the definition covers the important pieces: sort order, date and datetime encodings with a JST offset note, filter values, mode-dependent range rules, and the dividend-change coverage start date. It could say more about the shape of returned records (for example the details.changeFlag nesting it references) but is otherwise sufficient to call 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?

With schema coverage at 80%, the schema already documents to, from, types and symbol, so the baseline is 3. The description adds real meaning beyond it: the interplay between omitted symbol and required from/to, the 31-day maximum for whole-market queries, the 365-day default for single-company queries, and the explicit filter-by-types behavior. Only `limit` is left entirely to the schema.

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 names a concrete verb-plus-resource: a single date-sorted feed that aggregates TDnet timely disclosures, EDINET extraordinary reports, dividend changes, splits and delisting schedules. It also scopes the two modes (single company by default over 365 days vs whole market limited to 31 days), which lets an agent tell it apart from the narrower sibling tools such as get_disclosures, get_splits or get_delisting_schedule.

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 gives explicit operating conditions: omit `symbol` for the whole market only when from/to are supplied and the range is at most 31 days, and use `get_dividends` for dividend changes detected before 2026-05-18. That covers the main routing decision and the market-wide constraint. It stops short of stating when to prefer this feed over other per-type siblings, and gives no exclusion guidance.

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