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

Annotations already declare read-only, idempotent, open-world behavior. The description adds useful non-schema behavior: LEI check digits are verified locally, name searches return ranked candidates, and the response includes parent entities and registration details. It does not mention error handling or rate limits, but adds meaningful context beyond the 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?

The description is front-loaded with the identity question and then packs the input modes and return fields into one dense but useful sentence. Every phrase appears to earn its place, though the long parenthetical field list slightly reduces scannability.

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 usefully lists the returned fields and explains both input modes plus local check-digit validation. It is nearly complete for a lookup tool, with the main gaps being the limit/parents parameter semantics.

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 50%: lei and name are documented, while limit and parents only have defaults and no descriptions. The description implies ranked-candidate behavior and parent data, but does not explain the limit parameter or that parents is a boolean toggle, so compensation is partial.

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 clearly states it retrieves a GLEIF LEI record and supports lookup by LEI or by legal name, making the resource and modes specific. It does not explicitly differentiate itself from the sibling company_lookup, which is the only meaningful gap for a 5.

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 implies two usage paths — exact LEI lookup versus name-based ranked candidates — but gives no explicit when-to-use guidance, exclusions, or comparison to alternatives like company_lookup. The agent can infer the modes but is not told which to prefer under what conditions.

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