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

Beyond the annotations, the description discloses critical behavioral traits: the quote is 'immutable', the URL is 'short-lived', and 'Opening or returning from Checkout does not prove payment; only the verified Stripe webhook can fulfill the quote and credit CPTM.' This is significant context that alerts the agent to the asynchronous fulfillment model.

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?

Three sentences, each serving a distinct purpose: main action, prerequisites, and a critical caveat. No redundant words. The description is front-loaded with the primary function and structured for easy parsing.

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?

The description covers the essential context for a payment-creating tool: the object created, the output (URL), required headers, idempotency key, and the payment verification caveat. Combined with the existing output schema and annotations, the description is comprehensive for an agent to understand and invoke the tool 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 description coverage is 100%, so the parameters are already fully documented. The description adds no extra parameter-level semantics beyond mentioning idempotency_key, which is already in the schema. 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?

The description clearly states the tool's function: 'Create an immutable USD-to-CPTM quote... then return a short-lived Stripe Checkout URL'. It identifies the specific resource (quote/checkout) and distinguishes it from sibling tools like get_funding_status or request_sandbox_funds by emphasizing the Stripe Checkout flow.

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 this tool: for funding a parent agent or gift target via Stripe Checkout. It mentions prerequisites (Authorization header and idempotency_key) but does not explicitly contrast with alternatives like request_sandbox_funds, which would warrant a 5.

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