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

With no annotations, the description carries the full burden, and it does disclose two useful traits: the call itself is free, and payments for listed tools run over x402 with USDC on Base. It does not say whether the tool is read-only (implied by "lists"), what permissions if any are needed, or anything about response size/freshness.

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 short sentences, front-loaded with the most decision-relevant fact ("Free.") before the content scope. No filler and nothing repeated from structured fields.

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 zero-parameter, no-output-schema listing tool this is close to sufficient: the agent knows what it returns (tool names, prices, payment instructions). A little more on the shape of the price data or on how the x402 payment step actually works would close the remaining gap.

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 takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the description correctly doesn't waste words on inputs.

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 gives a concrete verb and object set: it lists the available Chain Check tools, their prices, and payment methods. That distinguishes it from every sibling (address_label, contract_scan, gas_snapshot, token_risk, wallet_report) which are all analysis tools. It stops just short of a 5 because it doesn't explicitly frame itself as the catalog/meta tool relative to those siblings.

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?

"Free." implies an agent can call it without cost concerns, and the listing purpose implies it's the discovery step before calling paid tools, but this is never stated. There is no explicit "use this before/after X" or exclusion of any alternative.

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