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

Annotations already indicate non-readOnly and non-destructive. The description adds that it creates Stripe links for two scenarios, but does not disclose side effects (e.g., redirecting user), authentication needs, or the requirement that confirm=true. This is adequate but not rich.

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?

Two concise sentences: first sentence states the function, second provides a usage condition. No redundant or irrelevant 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?

Given the existence of an output schema, the description covers the dual behavior and usage condition. It does not mention the return type (URL) or the confirm requirement, but these are partially covered in the schema. Overall, fairly complete.

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 has 80% coverage with individual parameter descriptions. The description does not add significant meaning beyond the schema (e.g., explaining the confirm parameter's role). Baseline 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 it creates a Stripe Checkout link for new subscriptions and a Stripe Billing Portal link for existing subscriptions. It distinguishes itself from sibling tools like create_subscription by focusing on link generation, but does not explicitly contrast with that sibling.

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 explicit usage guidance: 'Use only after the user explicitly asks to upgrade or fix billing.' This gives clear context. However, it does not mention when not to use or suggest alternatives.

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