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

Adds genuinely useful traits not covered by annotations: it costs $0.01 USDC on Base via x402, the initial 402 fetch itself is unpaid, and results are informational not legal advice. readOnlyHint is consistent (it inspects, does not mutate). It stops short of describing what the lint/screening result actually returns, keeping it below a 5.

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-loads the purpose, then packs the mechanics, disclaimer, and cost into two short trailing sentences. Dense but every clause carries information; the only minor cost is the run-on enumeration in the opening sentence.

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 multi-phase tool with no output schema, the description explains the process well but never indicates what a result contains (pass/fail, lint findings, matched sanctions entries) or what happens on failure. Return-value behavior is the missing piece for an agent to interpret results.

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?

At 0% schema coverage the description must explain both parameters. The 'url' parameter is loosely covered by 'an x402 URL', but the 'method' parameter (GET/POST enum) is never mentioned or given meaning, leaving a required enum undocumented in both schema and description.

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 and resource ('Pre-check an x402 URL before paying') and enumerates exactly what it does: fetch the 402 unpaid, parse scheme/network/asset/amount/payTo, lint the challenge, and screen payTo against OFAC addresses. The resource (an x402 URL) is clearly distinct from the entity/wallet/name resources handled by the siblings, so an agent can route without opening the 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?

The phrase 'before paying' clearly establishes when to invoke it. However, it never names an alternative or exclusion, even though sanctions_check_wallet overlaps with its payTo-screening behavior, so the agent gets context but no explicit routing rules for the ambiguous case.

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