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

With no annotations, the description carries the full behavioral burden and does well: it discloses the deterministic nature of the assessment, the 0-100 risk score, the pass/review/fail verdict, and that sources plus a UTC timestamp are returned. It does not mention side effects, whether the call is read-only, latency/cost from multiple external registry lookups, or error behavior when an ID is not found.

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?

Two dense sentences with the value proposition front-loaded ('in one call'), followed by the source and output enumeration and then parameter hints. Every clause carries information — the source list doubles as the effective output contract — with no filler.

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 and no annotations, the description is the only place the return contract can live, and it covers sources, flags, score, verdict and timestamp adequately; it also resolves both parameters. Gaps remain around failure modes (invalid VAT, no registry match) and whether partial results are returned.

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 document both parameters, and it does: company accepts a VAT ID (preferred), registry number or name, and country is the ISO code needed when supplying a name. It adds real precedence guidance beyond the bare schema, though exact formats (VAT prefix conventions, ISO 3166 alpha-2 vs alpha-3) are unspecified.

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 deliverable — a counterparty due-diligence report — and enumerates the exact sources it aggregates (VIES, business register, EU/UN/OFAC/UK sanctions, EORI, GLEIF LEI, Peppol), which implicitly distinguishes it from the single-purpose siblings like verify_vat and screen_sanctions. It stops short of naming a sibling explicitly, so the routing is inferable rather than stated.

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 phrase 'in one call' implies this is the aggregated alternative to the narrower sibling tools, but the description never states when to prefer it over kyb_check, verify_vat or screen_sanctions, nor any exclusion or prerequisite. Usage is left to inference from the source list.

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