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

The description transparently states that the tool does not charge or enable autonomous spending, which are key behavioral guarantees. It also implies a side effect of creating a URL. However, it does not mention potential side effects like creating a customer or payment method object, so it is not fully exhaustive.

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, consisting of two clear sentences that convey the essential information without superfluous detail. It is well-structured and easy to parse.

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 provides enough context for an agent to understand the tool's purpose and limitations. It does not describe the output schema, but that is not strictly necessary for selecting the tool. Slight gap: it doesn't mention what the returned URL is for or any next steps, but overall it is complete enough.

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?

There are no parameters to describe, so the baseline of 4 applies. The description adds no parameter-related information, which is appropriate given the absence of parameters.

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 action: 'Create a Stripe Setup Checkout URL.' It also specifies the purpose (authorizing a reusable payment method) and explicitly differentiates it from charging or enabling autonomous spending, making the tool's function unambiguous.

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 explains what the tool does and what it does not do (does not charge, does not enable autonomous spending), which gives some context for when it might be appropriate. However, it does not explicitly mention alternative tools or specific scenarios for when to choose this over others, leaving some ambiguity.

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