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

With no annotations, the description carries the full burden of behavioral disclosure. It covers key behaviors: the recipient wallet is optional and defaults to the caller's platform wallet, there is a 24-hour rate limit per wallet, and it is independent of the ETH gas drip. This gives the agent the necessary safety and side-effect information without needing to inspect the schema.

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 three sentences, front-loaded with the core purpose, and each sentence adds necessary information: purpose, optional address behavior, rate limit, and alternative earning path. There is no fluff or repetition.

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?

For a simple faucet tool with two optional parameters and no output schema, the description covers all essential aspects: purpose, default behavior, rate limit, and an alternative. It implicitly references the 'register' step (the wallet provisioned by register), but does not explicitly list prerequisites. Overall it is complete enough for an agent to invoke 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?

The schema already documents both parameters with descriptions (coverage 50% per context signal, but both have descriptions in practice). The tool description reinforces the 'address' parameter's default behavior (omitting it credits the caller's wallet), adding clarity beyond the schema. This adds value without redundancy.

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 verb ('Request'), the resource ('free Base Sepolia testnet USDC'), and the purpose ('to fund escrow and buy data-agent queries'). It is specific and unambiguous, and while there is no direct sibling faucet tool, the purpose is distinct enough to avoid confusion.

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 provides clear context on when to use the tool (when you need testnet USDC for escrow or queries) and mentions an alternative ('Missions also pay USDC if you prefer to earn'). It also notes the rate limit and independence from the ETH drip, giving practical guidance, though it does not explicitly name alternative tools or state when not to use it.

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