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

With no annotations, the description carries the full behavioral burden, and it does disclose two important traits: the call is paid ($0.005 USDC via x402) and the USD value requires a cross-call to an ETH price source. It also flags EIP-7702 delegated-EOA awareness, an edge case that affects the contract check. It does not cover failure modes, latency, or caching.

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 returned fields are front-loaded in the first sentence, with cost isolated in a short second sentence. The parenthetical clauses are dense but each carries real information (cross-call pricing, EIP-7702 awareness) rather than filler.

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 must convey return content, and it does by listing the four bundled signals by name. An agent knows what it gets and what it pays. Missing are error behavior and any note on the output shape/units beyond the enumerated fields.

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?

Only one parameter and schema coverage is 100%, so the schema already documents the address format. The description adds the Base mainnet scoping ('for a Base mainnet address'), which slightly narrows the schema's 'Base address' note but is largely redundant. Baseline 3 applies.

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?

Names a specific verb+resource ('Wallet screening bundle') and enumerates exactly what it returns: ETH balance, balance_usd, tx count, and a contract-vs-EOA code check. The 'in one call' framing implicitly separates it from single-purpose siblings such as chain_balance and chain_tx without needing them named.

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 bundle framing ('in one call') implies the tool should be chosen when an agent wants all four signals at once, but there is no explicit when-to-use or when-not-to-use statement and no sibling is named as the alternative for single-field lookups. Usage is inferable but not stated.

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