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

Beyond the readOnly/openWorld annotations, it discloses the commercial model ($0.002 in USDC per successful call via x402 on Base, Solana or Arc) and that failed calls are not charged — critical for an agent deciding whether to retry. It also pre-empts a false expectation by stating that per-contract gas used is unavailable from this RPC.

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?

Three sentences, front-loaded with the returned payload, then the limitation, then the price. Nothing is redundant and the most decision-relevant facts (output content, cost) lead.

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?

An output schema exists, so return-value explanation is optional, and the annotations plus pricing/limitation notes cover the behavioral side well. The only shortfall is the absence of explicit routing guidance against the many sibling crypto data tools, which is minor for a read-only telemetry endpoint.

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 single parameter blockCount is fully documented in the schema (100% coverage), so the baseline is 3. The description only indirectly hints at the window via 'recent block' and 'next block's base fee' and adds no format or bounds detail beyond the schema.

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 names the exact resource (Ethereum EIP-1559 gas per recent block) and enumerates the returned quantities: base fee in gwei, gas used ratio, priority-fee percentiles at 10/50/90 from eth_feeHistory, and the next block's base fee. That level of specificity clearly separates it from neighbouring block-level tools such as crypto_mev_block_analytics or crypto_ethereum_staking_rewards.

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?

It states a data boundary ('Gas used by contract is not included'), which implicitly tells the agent this is not a per-contract gas consumption tool, but it never says when to prefer it over a sibling or what questions it answers best. Usage is implied by the content rather than declared.

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