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

With no annotations provided, the description carries the full burden and does substantial work: it discloses the $0.002 per-call cost, the accepted payment assets (USDC on Arc/Base/Solana, XNT on X1), and the two-call handshake required to complete a purchase. It does not describe error behavior for unknown or pending hashes, which keeps it out of the top band.

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?

Three dense sentences, front-loaded with the core purpose and chain scope before the payment mechanics. Every clause carries information, though the return-field enumeration and the payment sentence together make it longer than the minimum needed for a single-hash lookup.

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 payment-gated, no-output-schema tool this is close to self-sufficient: supported chains, returned fields, price, and the payment handshake are all covered. What remains unstated is failure behavior (invalid hash, transaction not yet mined, insufficient payment), which an agent would need when the call goes wrong.

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%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains that omitting `payment` returns terms rather than failing, and that supplying it completes the purchase inside the same call. That turns a cryptic signed-payload parameter into an understandable two-phase contract.

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 states a specific verb and resource ('Transaction status and receipt by hash') and enumerates what comes back: success or revert, from, to, value, contract created, gas used, fee paid, block and time. It also scopes the supported chains, which cleanly separates it from siblings like evm_block, evm_call, and evm_token_info.

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 x402 flow is spelled out explicitly: 'Call once without `payment` for the terms, sign them with your own wallet, call again with `payment`.' That is a genuine when/how-to-use instruction an agent could not infer. It stops short of naming sibling alternatives or stating when not to use this tool (e.g., pending vs mined hashes).

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