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

Annotations already cover read-only and open-world behavior, and the description adds substantial non-obvious context: the data source (public block explorer API), a per-call price of $0.002 in USDC via x402 on Base/Solana/Arc, and that failed calls are not charged. It does not, however, describe pagination or latency behavior.

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 core resource and scope, followed by exclusions and pricing, with no filler. It is dense but each clause (field list, hyperchain exclusion, pricing) carries information an agent needs.

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 an output schema present, return-field details need not be explained, and the description goes further by naming the source API, the exclusion boundary, and the billing model. Nothing an agent needs to decide to call or how to pay is missing.

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 `limit` parameter already documents the 1–20 range and default of 5; the description only restates the same range. Baseline 3 applies since the schema does all the work and no extra syntax or edge-case semantics are added.

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 (zkSync Era rollup batches from the public block explorer API), enumerates the returned fields (batch number, time, status, L1/L2 tx counts, chain ids), and explicitly excludes hyperchain data, which resolves the ambiguity created by the tool name. An agent can distinguish this from rollup siblings without opening the schema.

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 'newest N batches' framing implies the monitoring use case, but there is no explicit when-to-use guidance and no sibling is named as an alternative, despite near-neighbors like crypto_arbiscan_l2_rollup or crypto_optimism_superchain_tx existing.

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