Save payment method

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

The description discloses that a small real payment is created and charged then refundable, and warns that it moves real money irreversibly. This goes beyond the annotations (which already indicate destructive hint) by explaining the mechanism and consequences, adding significant behavioral context.

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 extremely concise with three short sentences: the purpose, the binding mechanism, and a strong irreversible warning. Every clause adds value, and the all-caps warning is impactful without unnecessary verbiage.

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 the tool's destructive nature, the description covers the essential side effect (charged then refundable) and irreversibility, aligning with annotations. It does not explain post-binding behavior or failure handling, but since an output schema is present and the operation is simple, this is adequate.

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?

All five parameters have schema descriptions covering 100%, so the tool description contributes little extra parameter semantics. It indirectly references the binding amount but does not add syntax or format details beyond what the schema already provides.

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: 'Save a payment method for recurring charges.' It specifies the resource (payment method) and the purpose (recurring charges), distinguishing it from sibling tools like create_payment or create_recurring_payment.

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 implies usage for binding a payment method for recurring charges, but it does not explicitly mention alternatives or when not to use it. The warning about irreversible money movement provides context, but there is no clear exclusion or comparison with other payment creation tools.

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