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

Annotations declare readOnly=false, openWorld=true and idempotent=true, and the description adds genuinely useful non-schema behavior: the tool is paid ($0.25 USDC on Base or Arbitrum One), requires an x402 v2 PAYMENT-SIGNATURE header, and expects the inputs POSTed as JSON to a specific paid_url. That payment and transport detail is exactly the kind of context annotations cannot convey; only the mechanics of what happens on payment failure are unstated.

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 gate purpose and verdict set, then payment mechanics. It is dense and mostly earns its space, though the paid URL is stated twice ('paid_url' and the literal URL) and 'Terms: trust_preflight' is terse to the point of being cryptic.

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 paid, open-world tool with five required parameters and an output schema, the description covers cost, chain, payment protocol and endpoint – enough to invoke it correctly, and return values need not be explained since an output schema exists. Idempotency semantics live in the schema rather than the description, which is a minor omission rather than a gap.

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 restates the four probed inputs (endpoint, action, amount, permissions) in gate terms, which adds light framing but no syntax or format detail beyond the schema, and it says nothing about the optional 'context' field.

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 names a specific function – an action gate that evaluates provider_endpoint, action, amount_usdc and permissions_requested – and states the four concrete verdicts (ALLOW, RESTRICT, ASK_HUMAN, QUARANTINE). It also cross-references the sibling names trust_report and trust_preflight, which helps position it, though the phrase 'probed unpaid' is ambiguous and the relationship to those siblings is only implied.

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 hints at context by labeling itself an 'action gate' and pointing to trust_preflight for terms and trust_report for the verdict, but it never says explicitly when an agent should call this instead of trust_preflight or trust_report. There are no stated prerequisites or exclusions beyond the payment requirement.

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