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

With no annotations, the description carries the full behavioral burden and does substantial work: it enumerates the four return verdicts (no_match, possible_match, confirmed_match, unable_to_determine) with confidence, sources and coverage_limitations, states the list coverage boundary, and discloses the pricing model ($0.02 per call, USDC on Base, x402). What remains undisclosed is auth/payment flow specifics (partially in schema) and any rate limiting or latency expectations.

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?

Five tightly packed sentences, front-loaded with purpose, then output contract, then limitations, then cost. Every sentence contributes a distinct fact and nothing is repeated from the name or schema.

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 annotations and no output schema, the description must supply the return contract itself, and it does so by naming the verdict enum and its accompanying fields. Coverage limitations, jurisdiction scope and pricing are all present; only minor operational details (payment handshake, latency, what 'possible_match' implies for action) are left implicit.

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 all six parameters, establishing a baseline of 3. The description adds marginal value by clarifying what the list set actually contains (BIS Entity List, Denied Persons, ITAR Debarred, SDN) and confirming the x402 payment model behind payment_signature, but it adds no syntax, defaults, or interaction guidance for name, country, min_score or limit.

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 specific verb and resource ('Screen a buyer or consignee against US export-control lists') plus the operational moment ('before selling or shipping'). It names the exact data source (US Consolidated Screening List, 11 lists) and the decision it supports, so an agent knows precisely what this tool does with no siblings to disambiguate.

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?

'Use when a deal may involve US-origin items or technology' states the triggering condition clearly, and the description adds explicit boundaries ('No EU/UK lists; not legal advice') that tell the agent when this tool is insufficient. No alternative tool is named, but none exists in the sibling set, so the only gap is the absence of a routing target.

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