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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), and the description goes well beyond them: it discloses the live on-chain allowance read from Base, flags the 'unlimited' vs 'already revoked' cases, and documents payment/auth mechanics ($0.02 via x402, prepaid x-credit-token header, 1 free call/day, no API key). 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?

The core purpose and the sibling distinction are front-loaded, which is the right structure. It runs long with em-dash-nested clauses and some framing copy ('the action half of approval hygiene'), plus a dense pricing block, but nearly every sentence carries actionable information.

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 an output schema present, the description needn't detail return values, and it still names the returned artifact (to + calldata). Inputs, routing, payment model, and the signer hand-off are all covered, so nothing an agent needs to invoke it correctly is missing.

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 required params and the optional wallet param are already documented in the schema. The description restates the required inputs and the meaning of the generated call (approve(spender, 0) on a token), adding only marginal semantics. Baseline 3 is appropriate.

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 precise verb+resource: it builds the ready-to-sign transaction (to + calldata) for approve(spender, 0). It explicitly separates itself from the sibling approval_advisor ('tells you WHAT to revoke; this builds the HOW'), so an agent can choose between them without opening either schema.

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?

Gives explicit when-to-use routing against the sibling (approval_advisor for identification, this for construction) and states the next step in the workflow ('Hand the result straight to a wallet or agent signer'). The preconditions (token, spender required) are also stated.

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