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

The description discloses important behavioral details beyond the annotations: authentication requirements, the sign-in instruction return if unauthenticated, the need to call again after sign-in, and that it does not count toward monthly searches. This adds significant context that the annotations do not provide.

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 short, front-loaded with the primary purpose, and every sentence adds value. Important warnings are highlighted, and there is 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?

For a simple tool with two optional enum parameters and no output schema, the description covers all essential aspects: what it returns, authentication requirements, the re-call instruction, and whether it affects usage limits. No critical information is missing.

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 input schema already provides 100% coverage of the two parameters, including enums and default descriptions. The tool description does not add any additional meaning to the parameters beyond what the schema already states, so the baseline score of 3 is appropriate.

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: 'Get Stripe checkout URL for subscription.' It uses a specific verb and resource, distinguishing it from sibling tools like get_pack_link and get_pricing. However, it does not explicitly differentiate itself from those siblings by name, which prevents a perfect score.

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 usage context, including the prerequisite to sign in first, what happens if not authenticated, and the need to call again after OAuth sign-in. It lacks explicit 'when not to use' guidance or named alternatives, but the context is sufficient for an agent to know when to invoke this tool.

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