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

Annotations cover the safety profile (readOnly, idempotent, openWorld), and the description goes well beyond them: explicit per-call price ($0.002 USDC on Base), the x402 payment handshake and retry mechanism, and the exact response payload including L1 fees and log counts. This is the kind of context an agent needs to invoke it successfully and handle the failure path.

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?

The use case is front-loaded and the payment mechanics come last where they belong. The long mid-sentence enumeration of return fields is dense but each item is a real output the agent may key on; it is slightly over-stuffed for a single paragraph.

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?

There is no output schema, so listing the returned fields is necessary and done thoroughly. Payment requirements, the retry path, and the parallel multi-chain scope are all present, leaving nothing essential for a correct invocation unstated.

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?

With one parameter at 100% schema description coverage, the schema already documents `tx`; the description only reinforces that the hash may belong to any of the eight chains. No added syntax or validation guidance beyond the schema, so baseline 3 applies.

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 (search/returns) and resource (a transaction by hash across 8 named chains), with the exact chains enumerated and the returned fields listed. The framing 'Got a tx hash but not the chain?' makes intent obvious, but it never names the closest sibling (tx_decode) to differentiate when both could apply.

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 opening 'Got a tx hash but not the chain?' gives a clear triggering condition, and the payment section explains the prerequisite flow (unpaid call returns PaymentRequired, retry with params._meta['x402/payment']). It does not state exclusions or explicitly route to alternatives such as tx_decode.

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