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

With no annotations, the description carries the full burden and does so well: it discloses transliteration of non-Latin names, that unscreenable names return HTTP 400 rather than a false clear, the exact price ($0.01 USDC on Base eip155:8453), the payment mechanism (x402 in params._meta), and the raw HTTP endpoint. That is unusually rich operational context for a payment-gated API tool.

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 sanctions scope and safety-critical behavior (no false clear) are front-loaded, and the sentences are dense with useful facts. The trailing pricing and endpoint block runs a bit long, but each element is operationally relevant rather than 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?

For a 3-parameter, unannotated tool with no output schema, the description is nearly complete on inputs, cost, and failure modes. The main gap is that nothing describes the shape of a successful screening result (hits, match scores, list provenance), which an agent cannot get elsewhere given output-schema absence.

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 days, names, and threshold are already documented, and baseline 3 applies. The description adds only marginal semantics — noting names are counterparties 're-screened' and implying batch support — without adding format or constraint detail beyond 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?

The description opens with a concrete verb and resource ('Sanctions screening against US OFAC, UK OFSI and EU lists') and names the covered lists, which is genuinely informative. However, it then claims the tool can 'Screen a name, a wallet address, a batch, or your own watchlist,' which overlaps heavily with the sibling tools check_sanctions__screen, check_sanctions__address, and check_sanctions__batch, leaving the agent unsure what is distinct about this one.

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?

There is no explicit when-to-use or when-not-to-use guidance relative to siblings, and the enumerated capabilities (name, address, batch, watchlist) actively blur the boundary with check_sanctions__screen/address/batch. The only differentiating signal is the required 'names' parameter being framed as 're-screen', which is implied rather than stated.

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