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

Annotations already cover readOnly/destructive/openWorld, yet the description adds non-obvious commercial behavior: $0.01/call via x402 USDC or card key, first 25 free, failed calls free, and that repeats are not free because each call is charged. It partially repeats the readOnly annotation ('reads or computes only and changes nothing'), and does not describe caching or freshness of the quoted price.

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?

Front-loads the resource and what is returned, then usage, then pricing — a sensible order with no filler paragraphs. There is some redundancy at the tail where 'reads or computes only and changes nothing' restates the annotation and 'each call is charged' echoes the pricing sentence.

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?

No output schema exists, and the description compensates well by naming the returned values and the concrete 21,000-gas transfer cost. Payment mechanics and free-tier limits are covered; the only gap is that the optional `only` result-filter is left entirely to the schema while the text claims no input.

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 description coverage is 100%, so the optional 'only' key-filter is fully documented by the schema, which sets the baseline at 3. The description actually works against this slightly by saying 'Takes no input' when one optional parameter exists, adding no meaning about filtering behavior.

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+resource ('Current gas price on Ink') and enumerates the returned fields (gas price, base fee, suggested priority fee, 21,000-gas transfer cost), which no sibling duplicates. It also names the distinguishing sibling ink_receipt for historical fees, so an agent can separate it from ink_gas_history and ink_estimate_gas without opening schemas.

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?

'Use before sending a transaction or to decide whether to wait' gives a clear trigger condition, and 'for the fee a past transaction actually paid use ink_receipt' gives an explicit alternative. It does not address the other near siblings (ink_estimate_gas, ink_gas_history), so it stops short of full when/when-not coverage.

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