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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful context beyond that: default time window, JST basis for the bounds, and the fact that records are sourced from TDnet documents. It says nothing about pagination, ordering, or how the 200/500 limit affects results.

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 core scope and default are front-loaded in the first sentence. The bilingual repetition and the date-format explanation add length, and the YYYY-MM-DD statement partly duplicates the schema's regex pattern, but the JST-versus-UTC distinction genuinely needs spelling out.

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 four-parameter, read-only listing tool with no output schema, the description covers scope, defaults, timezone semantics, and the fields returned. Only pagination and result ordering are left unaddressed, which is a minor gap given the schema carries the limit bounds.

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 75%, and the description compensates by clarifying that from/to are JST dates rather than UTC, which the schema does not say. It also reinforces the 'today' default for `from`. The `limit` parameter remains undocumented in the description, but its bounds and default are fully specified in 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 opens with a specific verb and resource ('Scheduled and completed delistings of Japanese listed companies') and names the returned fields (delisting date, status, source TDnet document). It is clearly distinguishable from every sibling, none of which cover delistings, though it does not explicitly contrast itself with any of them.

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 states the default scope ('Defaults to delisting dates from today onward'), which is genuine usage guidance, and the JST semantics of from/to imply how to widen the window. It never says when not to use it or points to any alternative tool for related corporate-action data.

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