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

Annotations already declare openWorldHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is partly covered; the description adds the per-call cost ($0.03/site) and the source constraint (page must be the company's own site, not a directory/lookup). It does not state in prose that a payment header is required for actual execution, though the price mention and the x_payment schema field imply the paid flow. No contradiction with annotations.

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?

Three dense sentences with no filler: cost, capability, and routing rule all front-loaded. The opening fragment ('Japanese company site to a standard profile JSON') is grammatically elliptical, which costs a point but does not obscure meaning.

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?

An output schema exists, so the description is not obligated to explain return values, and annotations cover the safety hints; the field list and the enrich_company routing make it sufficient for correct invocation. The only minor gap is that the prose never says the call is payment-gated, leaving that entirely to the x_payment schema description.

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%, so a baseline of 3 applies, but the description adds real selection semantics for the url parameter — it must be the company's OWN site, not a name or domain query — which the schema's generic 'Absolute http(s) URL of the input' does not convey. The x_payment parameter is left entirely to the schema, which is acceptable given its detail.

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?

Names a specific transformation (page -> standard profile JSON) and enumerates the exact output fields (name, address, representative, capital, contact), so the agent knows precisely what it gets. It also explicitly contrasts itself with the sibling enrich_company, making the two tools distinguishable 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?

States the selecting condition ('when you have the URL of a Japanese company's OWN site') and the negative case with the alternative to use instead ('for name/domain lookups use enrich_company (country_hint: jp)'). This is explicit when-to-use / when-not-to-use routing that most definitions lack.

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