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

The description thoroughly explains the tool's behavior: it returns a URL the user must open, the AI cannot complete the payment, and credits are added asynchronously after Stripe confirmation. This goes well beyond the sparse annotations and provides essential operational 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 concise and front-loaded with the core purpose. Each subsequent sentence adds necessary guidance about the payment flow and follow-up, with no redundant or filler content.

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 a complete operational picture: it explains the return value (a URL), the user's required action, and the post-purchase verification step. It lacks explicit error handling details but is sufficient for this straightforward purchase tool.

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 schema fully describes the package parameter with an enum that maps to prices and credit amounts, so the description doesn't need to add more. It meets the baseline for high schema coverage, but no additional parameter guidance is given in the description.

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: to purchase pipeline check credits and return a Stripe Checkout URL. It uses a specific verb and resource, and distinguishes itself from siblings like get_balance and get_pricing by focusing on the purchase action.

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 the tool (to buy credits) and directs the user to verify with get_balance afterward. It doesn't explicitly state when not to use it or offer alternatives, but the flow is well-defined.

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