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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses a real behavioral constraint the annotations cannot: each call costs $0.009 USDC via x402, i.e. it is a paid operation. It also names the data sources (Coinbase's x402 directory, OFAC sanctions list) and that the output includes a plain verdict. Rate limits and failure modes are not covered.

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 purpose and the decision context, followed by the returned data and the cost. The middle clause is a long enumerated run-on, but every element (payment history, age, balances, sanctions, seller status, risk score, price) earns its place for a single-call aggregator.

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 no output schema, the description carries the return-value burden and does: it lists the concrete fields an agent gets back (payments, USDC spent, sellers, last payment, wallet age, balances, sanctions result, seller status, risk score with verdict), plus the required input and the per-call price. Nothing needed to call or interpret it 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 coverage is 100% for the single `wallet` parameter, so the schema already defines it. The description adds the framing that the wallet belongs to an agent being evaluated (and implies Base chain via 'Coinbase's x402 directory'), but no new format or validation detail beyond the schema's 'Agent wallet address (Base)'.

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+resource+scope: a trust check on an agent's wallet before transacting, and enumerates the exact signals returned (x402 payment history, wallet age, balances, OFAC screen, risk score). It is unambiguous, but it never names or distinguishes itself from close siblings like agent_inspect, wallet, wallet_portfolio, x402_check, or sanctions, so the agent must infer the boundary.

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?

"trust check on an agent's wallet before you transact with it" gives a clear triggering context and timing. However, it offers no exclusions or explicit alternatives (e.g. when to use x402_check or sanctions instead), leaving the routing decision to inference.

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