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

The description carries far more than the annotations: it discloses the return payload (SDN ID, programs, match strength, list date), a liability caveat ('screening aid, not legal advice'), and the payment model ($0.005 USDC on Base per successful call via x402). The pricing note also explains the otherwise surprising readOnlyHint=false annotation, since each call settles a payment.

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 shape, caveat, usage trigger and cost all appear in a compact block with no redundancy, and the core purpose leads. The single-sentence enumeration of outputs and the trailing pricing clause make it slightly denser than ideal, but nothing is 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?

With no output schema, the description compensates by enumerating the returned fields. It also covers cost, payment rail, both optional inputs, and the legal-boundary caveat, so an agent has everything needed to decide and invoke 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 description coverage is 100% and both parameters are documented there, including the matching rule ('matches when every word appears in a listed name or alias') and the 'give address, name or both' instruction. The description restates the same input surface without adding syntax, format, or normalization detail beyond the schema, so the baseline 3 applies.

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?

A precise verb+resource statement: 'Screen a crypto wallet address or a person or company name against the US Treasury OFAC SDN list.' It names the exact data source, the accepted input types, and the covered asset coverage (BTC, ETH, USDT, TRX), which no sibling tool (contract-risk, wallet-audit, x402_check) claims.

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?

It gives a concrete trigger: 'Use before paying, onboarding or trading with a counterparty,' which tells the agent exactly when this tool belongs in a workflow. It does not name an alternative or state when not to use it, but no sibling performs sanctions screening, so the omission is minor.

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