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

Annotations provide readOnlyHint=true and destructiveHint=false, and the description adds substantial behavioral context: zero API key required, x402 SLA cost of $0.10 USDC, HTTP 503 without charge on upstream failures, and data_source field disclosing provenance. This goes well beyond annotations and gives the agent clear expectations for cost, failure, and data origin.

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 two sentences, front-loaded with the core purpose, then provides essential details (returns, source, cost, failure behavior) in a compact but complete manner. Every sentence adds value with no fluff or redundancy.

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?

Despite having only one parameter and no output schema, the description is highly complete: it states what data is returned (Gwei, USD cost, congestion, agent context), the source (public RPCs), cost, and failure response. No critical context is missing for an agent to decide invocation and interpret results.

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 0%, so the description must compensate. It indirectly covers the chain parameter by naming Ethereum, Base, and Solana, which align with the enum values, but it does not explicitly explain the 'chain' parameter or the 'all' option. The enum is self-explanatory, and the description provides partial semantic support, earning a baseline 3.

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 'Live gas price benchmarks for Ethereum, Base, and Solana' with specific verb and resource, and distinguishes it from sibling benchmark tools by focusing on gas prices. It lists exact outputs (Gwei, USD cost, congestion category), leaving no ambiguity about the tool's purpose.

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 implies usage context by naming the supported chains and mentioning x402 agent economy context, but it does not explicitly state when to use this tool over alternatives or provide exclusions. Sibling tools are clearly different benchmarks, so a user can infer when to use it, but explicit guidance is absent.

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