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

Annotations already declare destructive=true, openWorld=true, idempotent=false, and readOnly=false. The description adds that the link can be subscription or one-time and is scoped to the authenticated MCP account, which is useful context, but it does not explain what gets charged, whether the link expires, or what permissions are needed.

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?

A single front-loaded sentence with no filler or redundant wording. It is appropriately concise for a simple one-parameter tool.

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 tool has one optional parameter, no output schema, and annotations that cover the safety profile. The description explains the return value (a checkout session URL) but omits any explanation of productSlugs, leaving the invocation under-specified given the 0% schema coverage.

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?

Schema description coverage is 0% for the sole productSlugs parameter, and the description never mentions productSlugs or what the slugs represent. With no schema descriptions, the description fails to compensate for the gap, leaving the agent unable to know how to populate the parameter.

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 names a specific action ('Creates a checkout session URL') and resource ('checkout session'), and clarifies it can be subscription or one-time tied to the authenticated MCP account. It does not explicitly distinguish this from sibling tools like create_billing_portal_link, so it is clear but not fully differentiated.

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?

There is no explicit guidance on when to use this tool versus create_billing_portal_link or other create tools, and no prerequisites or exclusions are stated. Usage is only implied by the action itself.

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