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

Goes well beyond the readOnly/destructive annotations by disclosing that a malformed address returns 400 uncharged, that failed calls are free, that each successful call costs $0.01 via x402 USDC or a card key, and that the first 25 calls are free. It also restates the read-only nature, though that is already covered by readOnlyHint=true, so a small amount of the text is redundant with structured data.

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-loads the core purpose in the first sentence, then packs use guidance, example, pricing, and safety notes into a few dense sentences. Slightly overloaded with billing and example detail, but nothing is truly wasteful.

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 no output schema, the description fills that gap by describing exactly what the response contains (bytecode size, minimal-proxy flag, implementation target). Error behavior, cost, and side-effect profile are all covered, so an agent has everything needed to call it correctly.

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 there is a single required 'address' parameter, so baseline is 3; the description earns an extra point by supplying a concrete example address and stating the validation rule (malformed addresses rejected with 400).

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 — check whether a 0x address on Berachain is a contract or a plain wallet — and enumerates the returned facts (bytecode size, EIP-1167 minimal proxy status, implementation address). This clearly separates it from siblings such as bera_proxy and bera_balance.

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 ('before sending funds or approving a spender') and names the alternative for a different need ('for a fuller risk verdict use check_counterparty'). The when-to-use and when-to-use-something-else conditions are both spelled out.

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