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

The description adds materially beyond the annotations: it discloses that the call is 'signed', that each identifier is 'checksummed', and that the result is 'one verdict, one receipt'. Even with readOnlyHint and idempotentHint present, this provides useful behavioral context about validation and output without contradicting the annotations.

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?

The description is a single dense sentence that front-loads the core purpose, enumerates the covered identifiers, summarizes the output, and gives a pricing rationale. Every clause earns its place, and the copy is appropriately concise for an agent-oriented definition.

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 a complete 4-parameter schema, an output schema, and annotations covering idempotency and read-only behavior, the description provides sufficient context for an agent to invoke the tool correctly. It communicates the bundled validation scope, the single-verdict outcome, and the commercial reason to prefer it over individual checks.

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%, so the parameter semantics baseline is already met by the input schema. The description restates the identifier types but adds only marginal validation detail ('each checksummed') and does not explain individual formats or optionality beyond what the schema already documents.

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 verb ('Screen') and a clear resource ('a vendor's identifiers') and enumerates the four covered identifiers: IBAN, LEI, VAT, and UK company number. It also highlights the bundled nature and the 'verdict'/'receipt' outcome, which distinguishes it from the single-check sibling tools without needing to open their schemas.

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?

'Screen a vendor's identifiers in ONE signed call' and 'Half the price of four single checks' clearly signal when the pack is appropriate: when the agent needs multiple vendor checks together. It does not explicitly state when to prefer an individual sibling check, so it stops just short of a fully explicit when/alternative guide.

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