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

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds substantial behavioral context: keyless access to public CC0 data, fuzzy matching with ranked candidates for names, exact matching for LEIs, and the full list of returned fields including status and jurisdiction. This goes well beyond the annotation signals.

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 description is moderately detailed but well structured: purpose first, then return fields, then use-case context, then input modes. Every sentence earns its place, though the sanctions/EDGAR list is slightly expansive and could be trimmed without losing core 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?

With no output schema, the description carries the full burden of explaining return values, and it does: it enumerates LEI, legal name, operating status, jurisdiction, legal-form code, address, registration status, and last-update date. It also covers both invocation modes and the data source, making the tool fully understandable for an agent.

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 the schema already documents query as a company name or 20-character LEI and limit as max candidates. The description reinforces this with 'fuzzy match, returns ranked candidates' and 'Ignored for an exact LEI', but adds only marginal meaning beyond 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?

The description opens with a specific verb and resource: resolve a company name to an LEI or look up an LEI directly. It clearly distinguishes the tool's scope by naming the GLEIF public register and emphasizing the LEI as a global join key, which separates it from generic company-lookup siblings.

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?

It gives concrete use cases: disambiguating a company and cross-referencing against sanctions, SEC EDGAR, federal spending, and due-diligence tools. It also explains the two valid input modes. It does not explicitly name alternatives or state when not to use this tool, so it stops just short of a 5.

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