trust_screen

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

With no annotations, the description carries the full burden and discharges it: it declares the deterministic output, the advisory-only disclaimer, the fail-open-to-review failure mode, the exact cost and rail ($0.02 USDC on Base, 402 quote), quote verification criteria, spend-cap refusal behavior, and that the payer key stays local. This is unusually rich behavioral disclosure for a paid mutation-adjacent 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?

Front-loaded with purpose and output contract, then failure semantics, then routing, then payment mechanics. Dense but nearly every clause earns its place; the payment paragraph is long yet actionable for a paid tool, with only minor compression possible.

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 tool with no annotations and no output schema, the description covers the return contract (approve/review/decline), the failure behavior, the paid-rail prerequisites, and the sibling for deeper detail. Nothing an agent needs to invoke it correctly appears to be 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 schema already documents agent, amount_usdc, and merchant_domain. The description restates the two required inputs ('an agent and a candidate USDC amount') but adds no syntax, format, or edge-case meaning 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?

States a specific verb (screen) and resource (pre-payment counterparty), names the exact output set (deterministic approve/review/decline), and distinguishes itself from the sibling trust_agent_attestation by framing itself as the summary screen. An agent can tell it apart from trust_verify_status and trust_agent_attestation without opening a 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?

Clearly scopes usage to pre-payment screening and routes to trust_agent_attestation when full signal detail is needed, which is a genuine alternative-selection rule. It stops short of explicit when-not conditions (e.g. non-payment use cases), so it falls just short of the top band.

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