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

With no annotations, the description carries the full burden and does disclose a real behavioral trait: it is a paid endpoint billed per call via x402. What it leaves out is whether the payment flow is mandatory on every call, any rate limits, and failure behavior — though the payment mechanics are covered by the schema's paymentProof description.

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?

Two sentences, zero waste: the scope and ranking come first, the billing detail second. Nothing is repeated from the title or schema.

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 no-argument read tool this covers what is returned in substance (gas price, priority fee, Solana median, ordering) and the cost model, with the payment parameter handled by the schema. It stops short of naming which chains are 'supported' or the response shape, a minor gap given there is no output schema.

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% and the single paymentProof parameter is fully documented in the schema, including the 402 handshake. The description adds nothing about parameters, so the baseline 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?

States a specific verb and resource ('returns current gas price and priority fee'), scopes it ('every supported chain'), adds the Solana priority-fee median, and specifies ordering ('ranked cheapest to most expensive'). Against the sibling gas_price, the 'multi chain' framing makes the difference clear without opening either 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?

Cost (0.002 USDC per call) implies usage but there is no explicit when-to-use versus gas_price or other fee-related siblings, and no stated exclusions. Usage is only implicit in the scope sentence.

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