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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond the annotations: the data source (FCDO) and the cost model ('a few free samples a day, then $0.01 USDC per call via x402'), which matters for an agent deciding whether to invoke repeatedly.

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 short sentences with zero filler; the scope constraint is front-loaded and the pricing caveat follows. Every clause earns its place.

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 an output schema present, return values need not be explained, and the description covers source list, scope, and cost. It is nearly complete, missing only explicit routing to the sibling screeners for non-UK lists.

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 both 'name' and 'threshold' (default 80) are already documented in the schema, and an output schema exists. The description adds no parameter-level detail beyond what the schema provides, so the baseline 3 is appropriate.

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 the resource and scope precisely — 'Potential matches on the UK Sanctions List only (FCDO)' — and the word 'only' carves it out from the sibling screen/screen-us tools. The screening verb itself is only implied by the name, so it falls just short of a full verb+resource statement, but an agent can still tell it apart from its siblings.

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?

'UK Sanctions List only' implies the when-to-use condition (UK/FCDO targets) and implicitly rules out the US and generic screeners, but no alternative is named and no explicit 'use X when Y' guidance is given. The pricing note tells the agent it is metered but not when to prefer it over siblings.

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