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

Annotations only cover read-only/open-world/idempotency; the description adds substantial behavior: $0.01 per call with x402 (USDC on Base) and MPP payment channels, fuzzy matching that folds accents and accepts any script, and the critical caveat that an empty candidate list is a paid 200 that 'certifies nothing'. That is exactly the kind of non-obvious consequence an agent cannot get 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-loaded with the billing/payment mechanics an agent must know before calling, then the screening semantics, then the disclaimer. Dense and mostly waste-free, though the payment-channel detail is verbose enough to slightly crowd the functional content.

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?

An output schema exists, so return values need not be enumerated, yet the description still names the match fields (list, programs, name score, reasons). Combined with pricing, payment mechanism, matching behavior, and the explicit non-determination caveat, nothing an agent needs to call this correctly is missing.

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 coverage is 83%, so the schema already documents dob, type, country and min_score. The description still adds meaning by framing type/dob/country as re-rank inputs only ('only add reasons and re-rank') and noting any-script/any-accent folding, though it never mentions limit or min_score defaults.

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 specific verb and resource ('Screen a name against the US OFAC SDN and Consolidated lists') and names the exact fields of the returned matches. It also scopes itself against sibling screening services with 'Not UN, EU or UK', so an agent can distinguish it without opening any schema.

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 clear usage context — screening a party name, with optional type/dob/country only re-ranking — and an explicit scope exclusion ('Not UN, EU or UK'). What is missing is a positive directive on when to prefer this over siblings like entity_lookup or nonprofit_verify, but the screening context is unambiguous.

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