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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the 'reads or computes only and changes nothing' line is mostly redundant. What adds real value beyond the annotations is the cost model ('$0.01/call via x402 USDC or a card key, first 25 free; failed calls free') and the note that repeats are not free, which explains the practical consequence of idempotentHint=false. Data provenance (GLEIF, CC0) and the returned field set are also disclosed.

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?

Purpose and input modes are front-loaded, with usage, provenance, pricing and the read-only guarantee following in a logical order. The long enumeration of returned fields and the example LEI are somewhat dense but each carries information; trimming the read-only sentence that duplicates annotations would tighten it further.

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's list of returned attributes (legal name, status, jurisdiction, addresses, registration status, etc.) is exactly what an agent needs to judge result sufficiency. Combined with pricing, provenance, both lookup modes and example input, nothing material is missing for a 3-parameter read tool.

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 schema already documents lei as a 20-character identifier and name as an alternative, plus the 1-10 limit range. The description restates the mutual exclusivity ('by 20-character LEI, or search by company name for up to 10 matches') but adds no format, casing, or matching-behavior detail beyond the schema, so the baseline 3 applies.

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 ('Look up a Legal Entity Identifier from GLEIF') and enumerates both input modes (LEI or name search) plus the returned fields. This clearly separates it from siblings like check_counterparty, sanctions_check and vat_validate, which do different checks on an entity.

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?

Explicit use cases are given: 'KYB, counterparty checks, trade reporting and matching companies across systems,' which tells an agent the business context. It does not, however, state when NOT to use it or name the sibling to prefer (e.g. sanctions_check vs. this for screening), so the routing decision is only implied.

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