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

The description adds useful behavioral detail beyond the annotations: it states 'Pure computation — no RPC call needed,' and outlines the specific revert types handled (Error(string), Panic(uint256), custom errors, silent reverts). This gives the agent a clear model of the tool's capabilities and limitations, complementing the readOnlyHint and openWorldHint annotations.

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 four sentences, all information-dense and free of filler. It front-loads the primary purpose and then layers capabilities and usage details efficiently. No sentence is redundant or unnecessary.

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 decode tool with two parameters and no output schema, the description is quite complete: it explains what it decodes, the supported error types, the input requirements, and the pure computation nature. The only minor gap is that it does not explicitly describe the return format, but this is not critical given the tool's straightforward purpose.

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 already has 100% parameter coverage, and the description adds practical context by telling the user to 'Pass the hex revert data from a transaction receipt or eth_call error response,' which clarifies where the required parameter comes from. It also ties the optional 'abi' parameter to the handling of custom errors, adding meaning beyond the schema's basic description.

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 clearly states the tool's function: 'Decode raw EVM revert data from a failed transaction or mezo_testnet_call on Mezo testnet.' It uses a specific verb (decode) and resource (revert data), and the mention of 'Mezo testnet' distinguishes it from sibling tools like eth_decode_revert and mezo_decode_revert.

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 provides clear context for when to use the tool: when you have raw revert data from a failed transaction or eth_call error response. It also notes that it is 'Pure computation — no RPC call needed,' which helps differentiate it from RPC-requiring tools. However, it does not explicitly exclude alternatives or name sibling tools, 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.