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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior. The description adds valuable context beyond that: live public-index data, XLSX/CSV file output, and a 10-LEI cap with direct/ultimate parent or reporting-exception results.

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 usage trigger and then adds scope, output behavior, limits, and exclusions in three tight sentences. The opening keyword phrase ('lei parent company, lei lookup, or legal entity identifier lookup') is slightly repetitive but still serves discoverability.

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 annotations covering safety, a complete parameter schema, and an output schema, the description supplies the remaining important context: data source, file format, lookup limits, and exclusions. It would be fully complete if it pointed to the appropriate alternative for ownership-chart requests.

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 sole 'leis' parameter is already well documented with an example and the 10-LEI limit. The description restates the 10-LEI cap and adds parent-result context, but does not add syntax or format details 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 states a specific operation: retrieving parent-company data for up to 10 LEIs from public-index records. It distinguishes scope from ownership charts and beneficial ownership, but does not explicitly name siblings such as find_leis_by_name or verify_leis.

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 a clear trigger (when the user wants an LEI parent company or legal entity identifier lookup) and an explicit exclusion (not for full ownership charts or beneficial ownership determination). It stops short of naming which alternative tool to use instead.

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