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

Annotations only declare readOnlyHint, so the description carries most of the burden and does add real behavior: PER/PBR/dividend yield use period-end price, ratios are 0-1 decimals, ETFs return empty, and J-REIT rows follow a 6-month cycle with annualized ROE/DOE and a 12-month dividend aggregation rule. It loses a point for not stating ordering/pagination behavior beyond the schema's 'newest first' and for a garbled sentence ('The the annual dividend...') that muddies the settlement rule.

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 metric list is front-loaded and useful, but the description is bloated: the entire J-REIT and ETF explanation is repeated verbatim in Japanese, and the ISO 8601 date-format boilerplate (also bilingual) is generic across the whole tool set. Roughly a third of the text is duplication rather than added information.

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 carries the return-value burden and largely meets it by naming the returned metrics and explaining the tricky fields (annualDividend, dividendYield, dividendPerShare, eps) for J-REITs. Enough is present to call the tool correctly; only exact field names and row shape remain unspecified.

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. The description adds period-related context (J-REIT two-row years, annual-only dividend yield) but says nothing about limit or the annual/quarter enum beyond what the schema states, so 3 is the correct baseline.

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 (valuation and profitability metrics per period) and enumerates the metric families returned (PER, PBR, ROE, EV/EBITDA, etc.), so the agent knows exactly what data this yields. It explicitly contrasts itself with get_key_metrics_latest, making sibling discrimination possible 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?

Gives explicit routing: use get_key_metrics_latest for today's values, and get_etf_metrics / get_dividends for ETFs since this tool returns empty for them. Both a 'when to use the alternative' rule and an exclusion are stated, which is the top bar for this dimension.

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