decode_revert_reason_hex

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states what it decodes and the selector types, but it does not describe the return format, failure behavior, required input encoding (e.g., 0x prefix), or the apparently relevant payment requirement hidden in the parenthetical '(0.01 USDC on Base L2)'. This is a significant gap for a tool that likely charges a micropayment.

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 description is very short and the core purpose is front-loaded in the first few words. There is no redundant phrasing. The parenthetical '(0.01 USDC on Base L2)' is cryptic but not verbose, so the description remains efficient despite being slightly unclear.

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 tool with no output schema and no annotations, the description omits key contextual details: what the decoded result looks like, how to format the payload (hex prefix, ABI-encoded data), what happens on malformed input, and the exact meaning of the USDC payment note. An agent would likely need to experiment or consult external documentation before using this tool correctly.

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?

The schema has 100% coverage for both parameters, giving a baseline of 3. The description adds real semantic value beyond the schema by clarifying that the payload is a revert reason hex string and naming the expected selectors. It does not fully explain the paymentSignature parameter, but the schema already states it is for x402 settlement.

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 names a specific verb ('Decodes'), a resource ('EVM transaction revert reason strings'), and the exact input format ('Error(string) and Panic(uint256) error selectors'). This is distinct from sibling tools like decode_evm_calldata because it targets revert reason strings specifically, not general calldata.

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 description implies when to use the tool: when you have an EVM revert reason hex string and need the decoded reason. However, it provides no explicit guidance about when not to use it, nor does it mention alternatives like evm_trace_call_revert_debugger or decode_evm_calldata. The usage context is clear but not differentiated.

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