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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description would only need to add context. It does add genuinely useful behavior: malformed address/slot returns 400 uncharged, pricing model, and that repeats are billable. However, that last point sits uneasily with readOnlyHint=true – it explains non-idempotence in cost terms rather than operational terms, and does not say what happens when slot is omitted. With annotations covering the safety profile, this is decent but not rich behavioral context.

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?

A single dense paragraph that front-loads the operation and return format, then use cases, then guards and pricing. Most sentences earn their place, but the billing rules are stated twice ('Price $0.01/call… failed calls free' vs. 'each call is charged, so repeats are not free'), and the slot/address prose duplicates the schema 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?

No output schema exists, so the description correctly covers return values, error behavior, pricing, and the proxy alternative. The notable omission is what slot means when omitted (slot is optional, required is only address) – an agent cannot tell whether the tool defaults to slot 0 or errors.

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%, so baseline is 3; the description adds value by clarifying that slot accepts a decimal index or a 0x 32-byte key and by explaining why (mapping and proxy slots), plus a concrete address example. It does not state the default when the optional slot parameter is omitted, which is the main remaining semantic gap.

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 and resource ('Read one raw storage slot of a contract on Linea'), names the underlying RPC method (eth_getStorageAt), and specifies the return shape (32-byte word as number, and as address when applicable). It also distinguishes itself from the very similarly named linea_proxy, so an agent can disambiguate among the many sibling storage tools by chain prefix alone.

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?

Gives an explicit use case ('inspect contract state that has no getter, owners or implementation pointers') and an explicit alternative with its selection condition ('for proxies use linea_proxy'). The when-to-use and when-to-use-something-else are both stated, not implied.

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