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

Goes well beyond the readOnlyHint/destructiveHint=false annotations by disclosing the cost model ($0.01/call, first 25 free, failed calls free), the error semantics (malformed address = 400, no code = 404, both uncharged), and why repeats cost money despite identical results — which explains the idempotentHint=false rather than contradicting it. It also states plainly that the tool changes nothing.

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?

Purpose and detection surface are front-loaded in the first sentence; usage guidance, error codes, an example, and pricing follow in descending order of importance. No sentence is filler — even the pricing clause informs whether an agent should batch or repeat calls.

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?

Covers invocation, failure modes, cost, and the safety profile, which is enough to call it correctly. Because there is no output schema, the description should say more about the response shape (implementation address, admin/beacon values, kind label), which it only gestures at with 'names the kind found'.

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?

With schema coverage at 100% the baseline is 3, but the description adds real meaning: the address must be a deployed contract (404 if code is absent), format errors surface as 400 uncharged, and a concrete example address is supplied. It stops short of describing accepted address forms beyond the '0x' hint already in the schema.

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 ('find the implementation behind a proxy contract on HyperEVM') and enumerates the concrete mechanisms probed (EIP-1967 implementation/beacon/admin, EIP-1822 UUPS, legacy OZ layout, EIP-1167 bytecode) plus the output ('names the kind found'). This clearly distinguishes it from the many chain-prefixed siblings by naming the chain and from contract_risk by scoping the job to implementation discovery.

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 trigger ('Use before trusting or decoding a contract whose code can be swapped by its admin') and names the alternative for the adjacent need ('for a fuller risk verdict use contract_risk'). The agent knows both when to call this and when to escalate elsewhere.

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