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

Annotations only cover the mutation/safety profile; the description adds substantial context beyond them: how the applicable threshold is chosen (EU/EEA 0, Japan ~700, FATF 1,000), the 90-day EdDSA attestation validity, that names are keyed-hashed and never returned while addresses are stored, and the $0.005 x402 payment behavior including unpaid/failed call handling.

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?

Dense but front-loaded: the core action and threshold logic lead, with storage, alternative routing, and pricing following. Parenthetical threshold and pricing sentences are information-bearing rather than filler, though the paragraph is long enough that it could be split for scanability.

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, the description needn't explain return fields, yet it still flags the key outputs (packetId, verification URL, signed attestation). Combined with the threshold, pricing, and storage disclosures, nothing an agent needs to invoke it 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 description coverage is 100%, so the baseline is 3. The description goes further by explaining the semantics of amount_usd (determines whether travelRule.applies) and of the country parameters (they set the applicable threshold), which the schema alone does not convey.

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?

Specifies the exact verb and resource: screens originator and beneficiary of a crypto transfer and stores the result as a Travel Rule packet. It explicitly distinguishes itself from screen_wallet (quick address check) and verify_travel_rule_packet (checking a received packet), so an agent can route correctly without opening schemas.

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?

States the triggering condition ('when a transfer needs a Travel Rule record') and names both relevant alternatives with their distinct purposes. It also notes that each call stores a new packet, which warns against redundant invocation.

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