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

Annotations declare readOnlyHint=true, so safety is already covered; the description adds genuinely new behavior context, notably the disclosure source (annual securities report), that subsidiary rows are included, and that ratios are decimals where 0.039 means 3.9%. It does not say what happens when a company discloses nothing or how far back fiscalPeriod can reach, so it stops short of a 5.

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 purpose statement is front-loaded and precise, but the entire text including the date-format paragraph is duplicated in Japanese, doubling length for no new information to an English-reading agent. The ISO 8601 / add-9-hours paragraph is boilerplate that applies to no parameter in this tool's schema, so it does not earn its place.

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, describing the returned fields was necessary and is done, along with units and the consolidated-subsidiary dimension. For a two-parameter read-only lookup this is close to sufficient; only missing-data behavior and fiscal-period range are absent.

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% and both parameters (symbol, fiscalPeriod) are documented in-schema with examples and the omit-for-latest rule, so the description need not repeat them. The unit convention (0.039 = 3.9%) does add interpretation value for what the symbol/fiscalPeriod pair will yield, but is not per-parameter guidance; 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 resource (diversity indicators disclosed in the annual securities report) with an explicit scope (the reporting company plus each consolidated subsidiary) and enumerates the three metrics returned: women managers ratio, male childcare-leave rate, and gender wage ratio. An agent can distinguish this from siblings like get_workforce or get_employee_count on the strength of the metric list alone.

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?

Usage is only implied: an agent infers it should call this when it needs ESG/diversity disclosure figures for a ticker. The only explicit conditional is in the schema (omitting fiscalPeriod gives the latest annual report), and the description never names a sibling or says when another tool (e.g. get_workforce for headcount) is the better choice.

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