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

Adds substantial context beyond the annotations: exact pricing ($0.05/call), payment rail (USDC on Solana via x402), the required two-step challenge/retry handshake with the _meta["x402/payment"] field, and the equivalent HTTP endpoint. Payment and auth requirements are precisely the behavioral details the annotations cannot convey.

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 sentences, front-loaded with the core purpose, then the commercial/transport details. Every sentence carries operational weight, though the x402 parenthetical is dense and could be tightened.

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?

There is no output schema, so the description could have hinted at what a 'normalized record' contains (fields, coverage). It covers invocation and payment completely but leaves the return shape entirely opaque for an agent that must decide whether the result is usable.

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 the single parameter is already documented as a '20-character ISO 17442 LEI'. The description only restates 'by LEI code', adding no format, validation, or lookup-behavior detail 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?

States a specific verb and resource: 'Fetch a normalized GLEIF LEI record by LEI code.' The 'GLEIF LEI' qualifier distinguishes it from siblings like companies_uk_company, companies_uk_ownership, and companies_uk_search, though it never names them explicitly.

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?

The description gives procedural guidance on how to invoke it (call once to receive the PaymentRequired challenge, then retry with payment), which is useful for the x402 flow. However, it offers no guidance on when to choose this over the sibling company tools that also take UK company identifiers.

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