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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description still adds material behavior: 'Only non-zero holdings are returned' (filtering), live pricing via DexScreener (data source/freshness), and full auth/cost terms ($0.02/call over x402, x-credit-token header for unlimited calls, 1 free call/day, no API key). This is exactly the auth/pricing/rate-limit context the annotations cannot express.

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 token scope are front-loaded in the first sentence, with filtering, data source, and pricing following in a logical order. The pricing sentence is dense but every clause carries actionable info; no 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?

An output schema exists, so return values need not be explained. The description covers chain scope, token set, filtering, data source, and payment/auth mechanics, leaving nothing an agent needs in order 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?

One required parameter with 100% schema description coverage, so the baseline is 3. The description only restates 'Required input: address' and adds no format detail (e.g., checksum vs. ENS, chain assumption) beyond what the schema already conveys.

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 states a specific verb+resource ('Returns native ETH plus WETH, USDC, USDbC, DAI, cbETH balances for any Base address') and enumerates the exact token set and chain, so the agent knows precisely what it gets. It does not explicitly distinguish itself from close siblings like wallet_portfolio, wallet_networth, or token_balance, which is the only thing keeping it from a 5.

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?

Usage is implied by the scoping details (Base chain, fixed major-token list, non-zero only) and 'Required input: address', but there is no explicit when-to-use guidance or naming of alternatives among the many wallet/token siblings. An agent can infer this is a quick fixed-basket balance check, but must guess whether wallet_portfolio or token_balance is the better fit.

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