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

Annotations already declare read-only, non-destructive, open-world, non-idempotent, but the description adds substantial context beyond them: return shape (32-byte word as number and as address when applicable), 400 on malformed input and uncharged, per-call billing, and the non-idempotent charging semantics ('repeats are not free'). That is real value over the annotations.

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 operation, followed by usage, error behavior, example and pricing. Well organized and dense; the pricing/payment sentence is somewhat lengthy but is decision-relevant for a paid API.

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, but the description explains the return format, error behavior, charging model and usage scope. An agent has everything needed to invoke correctly and predict the response.

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 meaning beyond schema by noting the slot forms map to mapping and proxy slots and providing a concrete address example, which helps an agent construct valid input.

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 (read), resource (one raw storage slot), chain (Celo) and the underlying RPC method (eth_getStorageAt). It clearly distinguishes itself from celo_call and celo_proxy by naming the exact scope of a single slot.

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?

Explicitly says when to use it (contract state without a getter, owners, implementation pointers) and names the alternative for proxy cases (celo_proxy). Nothing is left to inference.

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