Start Card Setup

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

The description mentions what the tool does not do (cannot charge or read cards) but omits any side effects such as creating a setup intent or modifying state. Given destructiveHint is true, the absence of side-effect disclosure is a significant gap.

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 focused sentences. It is well-structured with no redundant information, and the security note adds value without bloat.

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 tool with no parameters and no output schema, the description provides sufficient context: what it returns, the scope, and a security consideration. It does not mention error conditions or authentication, but these are commonly assumed. Overall, it is complete enough for an agent to call 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?

There are no parameters, so the baseline is 4. The description does not need to add parameter details, and it does not claim any incorrect information about inputs.

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 returns a clientSecret for Stripe's payment element, with specific context about saved cards and customer scoping. It is specific enough to understand the tool's purpose, though it does not explicitly differentiate from sibling tools.

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 context (for saving cards in the browser) and provides a caution about the secret's limitations, but it does not explicitly state when to use this tool versus alternatives or include any prerequisites. Guidance is present but not explicit.

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