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

Annotations already cover read-only/idempotent/non-destructive, but the description adds substantive behavior: what is actually checked (receipt status, confirmations, transfer matching against recipient, token, minimum amount) and, importantly, the failure mode 'reports unavailable reads without claiming payment arrived'. Cost ($0.002) appears only in the title, not the description, which is the main gap for a paid 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-loads the core question, then the usage condition, then the checks performed, then the caveat. Every sentence carries information; no filler or repetition of the title.

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 does the right work by enumerating what a result covers and how inconclusive reads are reported. It does not mention the x402 payment/settlement flow or the price outside the title, which a caller of a metered tool would want.

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 tx, chain, token, payment, minAmount, recipient and holderWallet in detail. The description only restates the USDC default and the recipient/token/minimum matching idea, adding little beyond the structured fields.

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?

Opens with a specific verb+resource plus a plain-language framing ('Verify payment: did USDC arrive?') and names the scope: ERC-20 payments on Ethereum or Base. It implicitly separates itself from generic siblings like tx_explain and wallet_check by focusing on payment settlement, though it never names those siblings explicitly.

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?

'Use when an agent needs to verify an ERC-20 payment ... before delivering work' gives a clear triggering condition tied to the agent's own workflow. No explicit exclusions or named alternatives are given, so it stops short of a 5.

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