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

The description discloses cost ($0.001 per call), payment method (USDC over x402), and that failed calls are not billed. It also indicates the information returned (allowance, unlimited status, balance). It does not explicitly state read-only behavior, but the nature of the tool implies no side effects.

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?

The description is concise but informative, covering purpose, defaults, cost, and return behavior in three sentences. It avoids redundancy and is well-structured, making it easy to parse.

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?

Given that no output schema is provided, the description adequately explains what the tool returns (allowance details, owner balance, spendable amount, and payment requirements). It is complete enough for typical usage, though it does not specify the exact return format or structure.

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?

The input schema provides descriptions for all three parameters (owner, spender, token) with clear definitions. The tool description adds context like default to USDC and cost, but does not significantly enhance parameter meaning beyond the schema, which already has 100% coverage.

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 clearly states the tool's function: checking ERC-20 allowance on Base, including details on spender limits, unlimited approvals, owner balance, and spendable amount. It is specific and distinct from sibling tools like base_balance or base_transfer.

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 description explains what the tool does but does not explicitly compare it to alternatives or state when to use it versus other tools. However, given the specific functionality, usage is implicitly clear, but explicit guidance is lacking.

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