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

With no annotations, the description carries full responsibility for disclosing behavior. It only states the purpose, with no mention of whether the tool reads on-chain data, what inputs are required, side effects, or output format. Significant behavioral context is missing.

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 short and front-loaded with the core purpose. The 'Tx Explain:' prefix is redundant with the tool name, creating minor waste, but overall the description is efficient and easy to parse.

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?

The tool has three parameters, no annotations, and no output schema, yet the description gives no information about input requirements, which parameter to use, or the nature of the plain-English explanation. This is inadequate for an agent to invoke the tool confidently.

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. However, the schema descriptions ('Tx to process', 'Hash to process', 'Input to process') are nearly tautological and give no format or selection guidance. The description itself adds no parameter meaning, but per the rubric the high coverage keeps this at baseline.

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 clear verb and resource: 'Explain a transaction in plain English.' This conveys what the tool does, though it does not differentiate it from siblings like x402-tx-decode or x402-tx-status, so it stops short of a 5.

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?

No guidance is given about when to use this tool versus alternatives, nor which input (tx, hash, or input) should be provided. The description provides no context for selecting this tool over related transaction tools.

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