Payment methods create

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

The description discloses key behavioral aspects: no charge is made (setup mode only), the card is saved automatically upon completion, and the agent's role is limited to presenting the URL. This goes beyond the annotations which only indicate non-read-only, non-destructive behavior.

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 with two sentences. It provides necessary details about the return value and the agent's action, though the second sentence slightly repeats the instruction about presenting the URL. Overall, it is well-structured and not overly verbose.

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 there are no parameters and no output schema, the description sufficiently covers the context: the purpose, the setup mode, the no-charge aspect, and the agent's next steps. It does not mention edge cases (e.g., existing cards), but the essential information for using the tool is present.

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 tool has no parameters in the input schema, so there are no parameter semantics to describe. The description does not need to explain any parameters, and the baseline for zero parameters is 4.

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 purpose: returning a one-time Stripe Checkout URL for adding a payment card. It also specifies that it is setup mode only and that the card is saved automatically, distinguishing it from payment_methods_list.

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 gives explicit guidance on what to do with the response (present the checkout_url to the user) and states that there is nothing else for the agent to do. It also notes that only buyer principals should use this tool. However, it does not explicitly name an alternative tool, though the context among siblings makes it clear.

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