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

Annotations already establish the read-only, idempotent, non-destructive profile; the description adds material context beyond it: "Nothing is sent", the $0.001 per-call price, the accepted payment assets (USDC on Arc/Base/Solana, XNT on X1), and that failures surface a revert reason. That is pricing, side-effect and result semantics the annotations cannot express.

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 sentences with the core purpose front-loaded and no filler; the payment logistics are compressed but necessary. The dense parenthetical about accepted payment assets is slightly heavy yet still earns its place.

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?

No output schema exists, and the description compensates by naming exactly what comes back (gas units, gas price, fee, or revert reason). Combined with the payment flow and the no-side-effect guarantee, an agent has everything needed to call this 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?

Schema coverage is 100%, so the baseline is 3, but the description earns above baseline by explaining the otherwise opaque `payment` parameter — you first call without it to obtain terms, sign those terms yourself, then resubmit the signed payload. The remaining parameters (to, data, chain, value, from) are left entirely to the schema.

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 and resource ("Gas estimate before sending") plus the supported chains and the outputs the caller gets back: gas units, gas price, fee, or the revert reason. An agent can distinguish this from evm_call or evm_tx without opening any schema.

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?

"Gas estimate before sending" plus the explicit two-step protocol (call once without `payment` for terms, sign with your own wallet, call again with `payment`) tells the agent exactly how to invoke it successfully. It stops short of naming when to prefer a sibling tool such as evm_call for simulation, so it is not a full 5.

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