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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing that the two lookups run in parallel, that results are returned independently, that an explicit disclaimer accompanies them, that coverage is SDN-only, that a non-match is not clearance, and that the call is refused before payment if sanctions data is unavailable. These are material behavioral facts an agent could not infer from 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?

Front-loads the core purpose and every sentence carries weight: scope, return contents, disclaimer, coverage limit, and refusal condition. The first sentence is a dense multi-clause construction, which slightly taxes readability, 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 output schema, the description compensates by describing what comes back (both independent results plus an explicit no-verified-link disclaimer). For a read-only, two-parameter combined lookup with annotations covering safety, an agent has everything needed to call it correctly and interpret the result.

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 schema already documents both parameters, making the baseline 3. The description reinforces the meaning of 'wallet' (EVM, OFAC-screened) and 'company' (UK Companies House KYB) but adds no syntax or format detail beyond the schema's own descriptions.

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 precise verb+resource combination: an OFAC SDN wallet screen plus a UK Companies House KYB lookup executed in one call. The phrase 'in one call' implicitly differentiates it from the sibling screen_wallet and verify_uk_company operations that would otherwise be needed separately, and it names the exact scope (EVM wallet, SDN list, UK Companies House).

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?

'Combined counterparty due diligence in one call' implies the usage case (when you need both checks) but never explicitly names the alternatives or states when to prefer this over calling screen_wallet and verify_uk_company individually. The refusal condition ('Refused before payment if current sanctions data is unavailable') is the only conditional guidance, and it addresses failure behavior rather than tool selection.

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