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

Annotations already declare readOnlyHint, destructiveHint=false, openWorldHint and idempotentHint=false. The description adds genuinely non-obvious context the schema/annotations cannot express: $0.01/call via x402 USDC or card key, first 25 free, failed calls free, and that repeated calls are billed again — which explains the idempotentHint=false in cost terms. It does not add much else beyond restating 'reads or computes only and changes nothing.'

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-loaded with the resource and return contents, then usage, then cost. Slightly redundant at the tail: 'each call is charged, so repeats are not free' restates the $0.01/call and free-tier facts already given, though the repeat-billing emphasis is arguably worth the words.

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 carries the return-shape burden and does so by naming the three fee components plus a concrete transfer cost. Pricing, failure behavior, side-effect freedom, and the sibling boundary (scroll_receipt) are all covered, leaving nothing an agent needs before calling.

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 optional `only` filter is fully documented in the schema, so the baseline is 3. However, the description says 'Takes no input,' which is mildly misleading given an optional result-trimming parameter exists and is never mentioned — an agent reading only the description would not know it can request a smaller payload.

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 Scroll (eth_gasPrice)') and enumerates the returned fields: gas price, base fee, suggested priority fee in gwei, plus the 21,000-gas transfer cost. It also implicitly separates itself from scroll_gas_history (current) and scroll_receipt (paid fee), so an agent can route 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?

Explicit when-to-use ('before sending a transaction or to decide whether to wait') and an explicit alternative with the condition that selects it ('for the fee a past transaction actually paid use scroll_receipt'). No alternatives are left to inference.

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