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

No annotations are provided, so the description carries full burden. It discloses an important behavioral fact the schema cannot: it costs $0.001 USDC on Base via x402. However, it omits auth requirements, failure behavior, and what happens when a supplied token address is invalid or the network is unsupported.

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?

Three tight, front-loaded sentences: what it returns, who it's for, and what it costs. No filler, and the most decision-relevant information leads.

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 and no annotations, the description should do more. It covers scope, networks, and cost, but leaves the return shape (per-token results, decimals, error representation) and any auth or rate-limit behavior unstated for a call with 3 params.

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 description coverage is 0% for 3 params. The description informally covers tokens ('up to 20 caller-supplied ERC-20'), network ('Base or Ethereum'), and native ETH, adding real meaning beyond the bare schema fields, but it never explains the required address parameter or its format.

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 scope: 'Live wallet balance in one call: native ETH plus up to 20 caller-supplied ERC-20 token balances on Base or Ethereum.' The bundling of native + up to 20 ERC-20 balances implicitly distinguishes it from single-purpose siblings chain-native-balance and chain-erc20-balance, though it never names them.

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?

Offers scenario context ('Built for portfolio agents, treasury monitors, wallet intelligence and recurring balance polling'), which implies when it fits, but gives no explicit when-to-use-instead-of guidance and no exclusions relative to the single-balance siblings.

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