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

With no annotations, the description carries the full behavioral burden. It discloses the shape of the output and the word 'Live' implies a real-time network fetch rather than cached data, but it omits rate limits, latency, failure modes on unsupported chains, and any auth requirements. For a low-risk read operation this is adequate but leaves clear gaps.

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 dense sentences with zero filler, front-loading the core subject and following with the supported-chain constraint. Nothing could be removed without losing 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?

With no output schema, the description must describe return values, and it does so concretely (base fee, tiered tips, maxFeePerGas, action costs) for a one-parameter tool. The only real gap is behavior on an unsupported chainId and freshness guarantees, which are minor for this tool's complexity.

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 parameter is documented with an example (8453 for Base), so the baseline would be 3. The description adds genuine value the schema lacks: an enumerated allow-list of supported chain ids (1, 8453, 42161, 10, 137, 56) that the schema does not express as an enum, preventing calls to unsupported chains.

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 a specific resource (live EIP-1559 gas per chain) and enumerates exactly what the response contains: base fee, slow/standard/fast tips, maxFeePerGas, and action costs. This is unmistakably distinct from the sibling tools (address_info, check_token, check_x402_payability, scan_contract), none of which deal with gas pricing.

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?

Usage is implied by the enumerated return values and the explicit list of supported chains, which functions as an implicit constraint on the chainId argument. However, there is no statement of when to prefer this tool, no guidance for unsupported chains, and no mention of alternatives for historical or non-EIP-1559 gas data.

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