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

Annotations already cover readOnlyHint and openWorldHint, but the description adds material context they don't carry: the x402 pay-per-call cost of $0.002 USDC and the pre-broadcast ordering constraint. It does not describe failure modes for malformed/short calldata, keeping it below a 5.

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 tight sentences, front-loaded with the operation and its scope, then the reason to use it, then the pricing. No filler or redundancy.

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 must communicate what comes back, and it does so field-by-field (type, chain, sender, fee caps, access lists, hash). Combined with the disclosed payment model, an agent has everything needed to invoke and interpret it.

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?

Only one parameter, and schema coverage is 100% (the schema already documents 'raw' as a 0x serialized transaction). The description's 'raw serialized EVM transaction' adds no format or validation detail beyond the schema, so the 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+resource (decode raw serialized EVM transaction) and enumerates exactly what is recovered: type, chain, sender, recipient, value, nonce, gas/fee caps, calldata selector, access and EIP-7702 lists, and resulting hash. The scope qualifier 'raw serialized ... before it is broadcast' cleanly separates it from siblings like tx_explain and tx_simulate without naming them.

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?

'Before it is broadcast' and 'Spot what a wallet is really being asked to sign' give a clear pre-signing verification context. It does not name alternatives (tx_explain, tx_simulate) or state when-not-to-use, so it stays short of the explicit routing a 5 requires.

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