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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable context beyond annotations by specifying the network ('Base mainnet'), unit ('wei'), and the monetary cost of invocation ('$0.005 USDC via x402'), which is not inferable from annotations or schema.

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 a single sentence that front-loads the action and resource, then adds the essential cost detail. There is no filler or redundant information.

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 simple zero-parameter, read-only tool, the description is complete: it states what is fetched, from which network, in what unit, and what it costs. No return schema is required to understand the expected output at this level of complexity.

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 tool has no parameters, so the schema already exhaustively defines the input surface. The description adds meaning by clarifying the returned unit and use case, which is all that is needed when there are zero parameters.

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 action ('Get'), the resource ('gas price on Base mainnet'), and the unit ('wei'), along with its intended use for transaction fee estimation. This distinguishes it from the other Base read tools in the sibling list, none of which target gas price.

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 gives clear context for when to use the tool ('for transaction fee estimation') and mentions the associated cost. It does not explicitly name alternatives or exclusions, but no sibling tool performs the same function, so the guidance is sufficient.

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