Company Lookup (GLEIF LEI, UK, Norway)

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

No annotations are provided, so the description carries the full burden, and it discloses two important non-obvious traits: the call is paid per call via x402 (USDC on Base) and coverage is limited to specific registries (GLEIF global, UK, Norway). It does not describe behavior on no-match, rate limits, or caching, so it is strong but not exhaustive.

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 accepted identifiers are front-loaded in the first clause, followed by output fields, sources, the usage trigger, and the payment note. The long enumerations of returned fields and registries are dense but each earns its place; nothing is padding, though the run-on construction 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?

With no output schema, the description correctly compensates by listing the returned fields (legal name, status, number, jurisdiction, address, incorporation date, legal form, officers, parent companies, source links) and explains the paid x402 flow. It omits no-match/error behavior, which is the only material gap for an 8-parameter 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% across all 8 parameters, so the schema already documents every field including auto-detection of the query and the payment signature. The description restates the identifier types and the officers/parent-company inclusion, which only marginally extends the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (company registry lookup) plus the three accepted identifier types (name, LEI, registry number). It enumerates the authoritative sources it queries (GLEIF, UK Companies House, Norway Brønnøysund) and the fields it returns, so an agent knows exactly what the tool does without opening the schema.

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?

Gives an explicit trigger scenario: verify a company exists, is active, and who owns it before onboarding, invoicing or contracting. That is clear prescriptive context. There are no sibling tools to disambiguate against, and no explicit when-not-to-use condition, so it stops just short of a 5.

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