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

With no annotations, the description carries the burden of behavioral disclosure. It usefully adds that the data is 'live' and that there is a 5-call free trial per registered wallet, providing cost and rate-limit context. It does not explicitly state that this is a read-only operation or describe output structure, though the 'Info' framing makes side effects unlikely.

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?

A single sentence packs the core function, supported chains, and a cost/limit notice with no wasted words; the most important information is front-loaded. Every clause earns its place, including the free-trial caveat.

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 simple two-parameter, no-output-schema read tool the description covers the main purpose and supported chains, but it does not explain acceptable values for 'network' or whether omitting both parameters yields a default. An agent would have to guess the network format, and the output (block height/gas) is only mentioned at a high level.

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%, so the baseline is 3; the description adds one meaningful piece of parameter guidance by listing ETH/Base/Polygon as valid chain values. The 'network' parameter remains vague—its possible values (mainnet, testnet, etc.) are not disclosed in either the schema or the description.

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?

Description identifies the resource ('Chain Info') and the exact data returned ('Live block height + gas') for ETH/Base/Polygon, which distinguishes it from sibling chain tools like x402-chain-compare, x402-chain-id, and x402-block-number. However, it lacks an explicit directive verb like 'get' or 'fetch', making the statement nominal rather than a clear command.

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 the primary use case—obtaining current block height and gas data on ETH/Base/Polygon—and notes the trial-call limit, which helps an agent decide if the call is affordable. It does not name alternatives or state when not to use this tool, which is a gap given the large set of sibling chain and gas tools.

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