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

Annotations already mark this as read-only and non-destructive. The description adds meaningful behavior beyond the annotations: it discloses the data source (public RPC), response format (JSON), and the cost in USDC via x402. This is useful operational context for an agent.

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-loaded, packing the core purpose, supported chains, units, source, response format, and pricing into a short text with no wasted words. Every sentence contributes actionable 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 one-optional-parameter read-only tool with no output schema, the description is quite complete: it states chains, units, source, response format, and pricing. The only minor gap is that it does not detail the exact JSON return shape beyond mentioning gwei/wei and JSON.

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 input schema already fully documents the chain parameter with its allowed values and default. The description restates the supported chains but does not add substantial new meaning beyond what the schema provides, so the baseline score of 3 applies.

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 specific verb/resource: it provides the current EVM gas price for Base or Ethereum mainnet. It also specifies units (gwei and wei), making the tool's purpose unambiguous and distinct from sibling tools like crypto_balance or crypto_token_report.

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 clearly indicates the tool is for retrieving current gas prices on Base or Ethereum, giving an agent enough context to select it. It does not explicitly name alternative tools or state when not to use it, but the purpose is specific enough that exclusion is largely unnecessary.

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