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

Adds meaningful behavior beyond annotations: it creates a live payment session, 'charges nobody by itself', and includes the 24-hour publication and refund policy. It does not discuss repeated invocation behavior or link expiry, but the annotations already flag non-idempotency, and the description covers the most important side-effect boundary.

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?

Four sentences, each carrying necessary information: core purpose, checkout behavior, user handoff instruction, and prerequisite. The parenthetical price and refund policy is compact, though the text could be slightly tightened without losing clarity.

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?

Together with the schema and annotations, the description fully equips an agent to select and invoke the tool: required parameter, optional prefill, prerequisite, output URL, and the mandatory user action are all covered. No material selection or invocation detail 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?

Schema description coverage is already 100%, and the description adds extra context for submission_id by constraining it to a submit_pwa handle less than 30 days old. The optional email is correctly described as a prefill; the description adds just enough beyond the schema.

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?

States a specific verb and resource: 'Create a Stripe Checkout link to upgrade an existing submission to Pro Launch' and includes the price and outcome. This clearly distinguishes the tool from the get/search/submit 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?

Gives a clear prerequisite ('submission_id from submit_pwa that is less than 30 days old') and an explicit execution rule ('Give the URL to the person you are working for and let them pay it — never attempt to complete the payment'). It does not explicitly name alternatives or a when-not-to-use case, but the intended trigger is clear.

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