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

Annotations already declare it read-only and idempotent, so no contradiction. The description adds pricing information and the exact HTTP endpoint for cross-referencing, but does not clarify that it performs a simulation without state changes or that the result is a gas estimate in wei. It adds some value beyond annotations but could be more explicit about the non-persistent nature.

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 compact and front-loads the core purpose, followed by pricing, chains, and an example. It is efficient with no fluff, though the example URL is lengthy and might be unnecessary detail.

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?

Given the tool has 5 parameters and an output schema, the description covers the main use case but lacks details on edge cases (e.g., what if 'from' is omitted, how the estimate is interpreted, or whether it supports token transfers beyond native value). It is adequate for basic usage but not comprehensive for complex contract interactions.

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 description coverage is 100%, so the schema already documents each parameter. The description adds context that the 'to' parameter is a contract address and that 'data' is hex calldata, but this is also in the schema. It does not clarify the default for 'from' (e.g., zero address) or the format of the returned estimate, so the description adds limited extra value.

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 purpose: estimating gas for a transfer or contract call, with specific reference to eth_estimateGas. It distinguishes itself from siblings like chain_call and chain_fee_data by focusing on gas estimation for a call the agent describes, without needing a wallet.

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 enough context for when to use it: when you need to estimate gas for a specific transaction before signing. It also lists supported chains and mentions pricing, but does not explicitly say when NOT to use it or suggest alternatives like chain_fee_data for general fee info.

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