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

Annotations only cover safety (readOnly, openWorld, non-destructive), so the description carries the rest and delivers: per-call price ($0.06 USDC via x402 across four chains), that payment happens inside the call, auto-payment behavior for x402 clients, and explicit failure semantics ('errors with Not charged'). That is unusually rich behavioral disclosure beyond structured fields.

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, return values, and the fallback path are front-loaded; pricing and the sample input follow at the end. It is dense but nearly every clause (DACH constraint, fallback, price, sample) earns its place. Slightly long with the x402 chain list but not padded.

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 still enumerates the return content (grade, verdict, reasons, sanctions, VAT, domain security), plus the error path, the fallback tool, the cost model, and a sample invocation. An agent has everything needed to decide and call correctly.

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 coverage is 100% and the single 'domain' parameter is fully documented ('Website domain, e.g. example.de'), so the baseline is 3. The description adds a concrete worked example ({"domain":"sap.com"}) and ties the parameter to the geographic constraint (imprint must exist), giving it marginal value above 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 chain: reads the imprint to find the legal entity, then runs a KYB check returning a grade (A-F), a verdict (ALLOW/CAUTION/BLOCK), plus reasons, sanctions, VAT and domain security. This clearly distinguishes it from the sibling kyb_check, which it explicitly routes to when no imprint exists.

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 when ('Use to vet a counterparty from its website'), a when-not condition (requires a DACH imprint, otherwise it errors with 'Not charged'), and the alternative to use instead (kyb-check with the company name). All three routing signals are present without inference.

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