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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: the 16-word bound, the $0.001 USDC cost per call, the supported chains, and the byte-identical REST endpoint. It doesn't describe pagination or error behavior, but the bound and cost are the key behavioral traits an agent needs.

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 sentences with zero waste. The core capability and use case are front-loaded, followed by cost and chain list, then the REST equivalent. Every sentence earns its place.

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?

The description is complete for a read-only storage-range tool: it states the bound, cost, supported chains, and REST equivalent. The output schema exists, so return values are covered. The only minor gap is not explicitly stating what happens when count exceeds 16, but the 'up to 16' phrasing implies the bound.

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 schema already documents all 5 parameters. The description adds the 'up to 16' bound and the '32-byte words' unit, which clarifies count semantics, but doesn't add much beyond that. Baseline 3 is appropriate since the schema does the heavy lifting.

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 description clearly states the tool reads up to 16 consecutive 32-byte storage words from any starting slot, with a concrete use case (walking a struct or mapping array). It distinguishes itself from chain_storage and chain_storage_diff by emphasizing the range/sequence aspect and the byte-identical REST endpoint.

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 when to use it (when you need to walk a struct or array behind a mapping rather than trust a view function) and provides a concrete REST equivalent. It doesn't explicitly name sibling alternatives like chain_storage or chain_storage_diff, but the use-case framing gives clear context. The cost disclosure also helps an agent decide whether to use it.

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