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

With no annotations, the description carries the burden and does a good job: it discloses the keyless/no-API-key auth model, the upstream source (api.gleif.org Golden Copy), the returned fields (LEI, jurisdiction, registration status, LOU), and the $0.005 USDC x402 cost on Base. It doesn't mention rate limits, caching, or error behavior, so it falls short of a 5.

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 operational details are front-loaded and useful, but the sentence is bloated with SEO keyword stuffing ('Matches: LEI, GLEIF, legal entity identifier, LEI lookup, company LEI') and a bracketed endpoint/pricing restatement that duplicates the earlier cost line. Those clauses don't help an agent select or invoke the tool.

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?

For a 3-optional-param lookup with no output schema and no annotations, the description supplies source, auth model, cost, and the shape of returned fields, which is close to sufficient. It leaves out response structure details and any guidance on which key to prefer, keeping it short of a 5.

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 the schema already documents all three parameters including the 20-char LEI format and the domain-to-name mapping. The description's 'by LEI code, legal name, or domain' adds nothing beyond the schema. Baseline 3 is appropriate.

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+resource (GLEIF LEI lookup / Legal Entity Identifier search) and names the three lookup keys (LEI code, legal name, domain). The resource is distinct enough from the deep-research and enrichment siblings that an agent can recognize it without opening the schema, though it never explicitly contrasts itself with them.

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 describes the data source and payment model but gives no when-to-use guidance, no conditions for choosing LEI vs name vs domain, and no alternatives named against the many sibling lookup/enrich tools. The agent must infer invocation context.

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