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: it discloses the cost ('Costs 10 tokens'), the dividend-yield calculation rule (forecast dividend when available, actual otherwise), and clarifies that 'consecutive non-decrease years' counts flat years. It does not describe the shape of results or how ties/missing metrics are handled.

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?

Two short sentences with the core ranking purpose front-loaded, followed by the one metric-specific caveat that matters. The duplicated Japanese title fragment adds little but costs almost nothing.

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 and four parameters, the description should ideally indicate what a ranking row contains (company identifier, metric value, rank) so the agent can plan downstream use. The purpose and metric semantics are complete, but the result shape is 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 75% and the metric enum is largely self-documenting, but the description adds real meaning beyond it: 'price change' and 'CAGRs' map the changePct*/Cagr enum values into plain language, and 'consecutive non-decrease years (including flat years)' disambiguates progressiveDividendYears. The limit, order, and sector parameters are 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?

States a specific verb and resource — 'Top/bottom ranked Japanese listed companies by a single metric' — and enumerates the metric families, which separates it in spirit from screening tools like screen_stocks. It never names an alternative explicitly, so sibling differentiation is implied rather than stated.

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?

The 'top/bottom' framing implies the use case (finding leaders or laggards on one metric), and naming a single metric implicitly excludes multi-criteria screening. There is no explicit when-to-use vs. screen_stocks/run_screener_preset guidance and no stated exclusions.

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