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

Annotations already establish readOnlyHint and openWorldHint; the description adds pricing ($0.002 USDC per successful call via x402 on Base, Solana, or Arc) and that failed calls are not charged. That is meaningful operational context beyond annotations, though rate/latency details are absent.

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 front-loaded sentences cover the payload, scope exclusion, and pricing. The list is dense but every sentence carries operational or scope information, with no wasted wording.

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 single-parameter stats tool with an output schema and readOnly/openWorld annotations, the description covers the data returned, the key exclusion, and the payment model. Nothing material is missing for correct invocation.

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?

There is only one optional parameter, 'blocks', and schema description coverage is 100% with the 1–10 range and default already documented. The description repeats the 1–10 range but adds no further semantics, so the baseline 3 is appropriate.

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 first sentence names Scroll (zkEVM L2) and lists concrete metrics: blocks, transactions, block time, gas prices, utilization, and newest blocks. The exclusion of proof and batch-finalization status clarifies scope, though the tool name 'zk_proofs' is somewhat misleading and no sibling routing is provided.

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 gives clear data context and one when-not condition: proof and batch-finalization status is not reported. However, it never states when to choose this over sibling L2 tools or other gas/network feeds, so usage is mostly implied.

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