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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior, and the description adds meaningful context beyond that: screening signals are coverage-gated and returned as 'not_rated' until the 14-day/20-payment floor, measured graph facts are always returned and carry no intent inference, and the call costs $0.008 USDC via x402. This gives the agent a solid model of what the call will and will not reveal.

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?

Every sentence earns its place: the first lists the returned data, the second states the intended use, the third explains the coverage-gating caveat and intent-neutrality, and the fourth gives pricing. Information is front-loaded and dense without being bloated.

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 single-parameter read-only tool with no output schema, the description covers what data is returned, how screening signals behave under insufficient data, what the caller should use the data for, and the cost. Nothing essential for correct invocation or interpretation 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?

The schema already fully documents the single address parameter with a regex pattern, example, and description, so the description carries little additional parameter burden. It does reinforce that the address is the paying wallet, but this adds only marginal meaning beyond the schema.

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 resource (a paying wallet's know-your-agent profile) and enumerates the concrete facts it returns: distinct services paid, observed spend, contract vs. externally owned account, and screening signals. It also states the intended action, 'vet a counterparty that is paying you,' which clearly separates it from sibling tools like wallet_authenticity or revenue_estimate.

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 explicitly tells the agent when to use the tool: to vet a counterparty that is paying you. It does not explicitly name alternatives or when-not-to-use conditions, but the use case is specific and clearly scoped relative to the sibling list.

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