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

No annotations are provided, so the description carries the full behavioral burden. It does usefully disclose the return shape (a pass/review/fail verdict with reasons), which is the single most important behavioral fact given there is no output schema. However, it says nothing about cost, latency, external-registry dependencies, failure modes when the register is unavailable, or whether it is a read-only operation.

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?

Front-loaded with the core purpose and scope in the first sentence, followed by parameter hints in the second. The '+' separated component list is dense but readable. Slightly run-on, with no whitespace separating the parameter guidance from the capability statement, but nothing is wasted.

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 annotations and no output schema, the description does the heavy lifting: it lists the underlying checks, discloses the verdict format, and gives input formats for two parameters. The gaps are the undocumented 'requester' parameter and any operational context (cost, failure handling) for a tool that fans out to multiple external registries in one call.

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 0%, so the description must compensate, and it does for two of three parameters: 'company' is documented as accepting a VAT ID ('FR40303265045'), a company name, or a registry id, and 'country' is documented as an optional ISO code (e.g. 'NO'). The third parameter, 'requester' (defaulting to 'HU33119856'), is never mentioned and its cryptic default is unexplained.

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 names a specific operation on a specific resource ('One-call KYB check of a supplier/customer') and enumerates exactly what it covers: VIES VAT validation, official business register lookup, and EU/UN/OFAC/UK sanctions screening, plus the pass/review/fail verdict it returns. This composite scope implicitly separates it from the single-purpose siblings (verify_vat, screen_sanctions, lookup_company) that perform only one of those checks.

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?

'One-call' frames the tool as the consolidated alternative to running the individual checks, and 'KYB check of a supplier/customer' makes the onboarding/verification use case clear. It stops short of explicitly naming the sibling tools or stating when-not to use this (e.g., for a VAT-only lookup where verify_vat is cheaper), so the routing condition is implied rather than stated.

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