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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing pricing ($0.002 USDC per call over x402), that failed calls are free, the 3-free-calls-per-day policy, and the quote-then-pay flow via the payment parameter. This is exactly the extra context annotations cannot carry.

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 what the tool does, then cleanly sectioned into when-to-use, alternatives, parameters, and returns. Some content (chains, tokens, returns) is repeated across the body and the Parameters/Returns sections, but every section is useful.

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 carries the return shape itself (native coin, USDC/USDT, listed tokens with symbol, decimals, amount), and it covers payment flow, pricing, and alternatives. 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%, so the schema already documents address formats, chain enum, and the 20-token cap. The description largely restates these ('address is required', 'chain: base default', 'tokens: up to 20'), adding only the cross-parameter constraint that the address format must match the chain, which the schema already implies.

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 (checks a wallet's token balances) and scopes it precisely across chains, naming exactly which balances are returned. It distinguishes itself from wallet_portfolio and check_my_balance by naming both.

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?

Has explicit 'When to use' and 'Use instead' sections that route the agent to wallet_portfolio for USD totals and check_my_balance for the caller's own USDC. Alternative selection is fully specified, not inferred.

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