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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), and the description adds genuinely useful behavior beyond them: the two named upstream registries, the 'never fabricates' guarantee, and the explicit honest not_found response with sources queried. Note the tension with openWorldHint=false given it calls public external registries, though that is a borderline inconsistency rather than a direct contradiction.

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 the capability stated first, the sources second, and the honesty guarantee last; the [free, no key] tag is front-loaded at the end as a scannable marker. No filler or repetition of the title.

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 compensates by enumerating the returned fields and describing the not_found behavior, so an agent knows what to expect. The only shortfall is that lookup precedence between the optional lei and name parameters, and result format, remain unstated.

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 each of the three parameters carries its own description (lei = 20-char identifier for precise lookup, name = legal company name, country = ISO 3166-1 alpha-2 filter). The description does not add parameter-level detail, so the schema is doing all the work; baseline 3.

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 (verify/lookup) and resource (company official registry record), and names the exact data sources queried (GLEIF LEI registry, SEC EDGAR) plus the fields returned. An agent can separate this from siblings like screen_sanctions or check_compliance without opening any 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?

Describes the context in which it applies (free, live lookups of corporate registration data) and the failure mode, but never states when to prefer it over the nearby siblings (screen_sanctions, check_compliance, map_trade_restriction) or what inputs make it inappropriate. Usage is implied rather than prescribed.

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