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

With annotations present, the description adds real behavioral context beyond them: the $0.005 USDC-on-Base cost per successful call via x402, the EOA-nonce caveat (outgoing transactions only), and the explicit statement of what data it does not return. That pricing and nonce-semantics detail is not available anywhere in the structured fields.

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 resource and contents, then caveats, then the use case, then pricing. Dense but every clause carries information; the long token enumeration in the first sentence is the only mild bloat.

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, and the description compensates by enumerating the returned fields (balances, nonce, account type) and the payment model. What an agent needs to decide and call is largely present; only the return shape for the extra-token addresses is left implicit.

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 100%, so both parameters (address, tokens) are already documented in the schema; the description's 'up to 20 extra token addresses you pass' merely restates the schema's max-20 constraint. Baseline 3 is appropriate when the schema carries the parameter burden.

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?

The description names a specific resource and scope ('live snapshot of any address on Base') and enumerates exactly what the snapshot contains: ETH balance, a named list of major tokens, up to 20 extra tokens, nonce, and account classification (EOA/contract/EIP-7702). It also fences off what it is not (transaction/token-transfer/trading history). It stops short of naming the sibling primitives it bundles (base_balance, base_nonce, base_is-contract), so an agent must infer the overlap rather than being told.

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?

'Use to check a counterparty's holdings' gives one concrete use case, and the 'not full transaction history' clause implies when to look elsewhere. However, no alternative is named (e.g. use base_balance for a single-token check, wallet-audit for deeper inspection), and there is no explicit when-not guidance beyond the history exclusion.

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