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

Beyond the annotations, the description adds essential behavioral details: checkout is not completed until a person opens the URL in a browser, no charge occurs during creation, and predictable errors occur when the listing is missing, the add-on is free early access, or payments are not configured. This gives the agent an accurate model of side effects without contradicting the annotations.

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 compact and front-loaded: the first sentence states the outcome, the second sets the buyer-authorization expectation, and the third lists failure cases. Every sentence adds distinct value with no filler.

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 required parameters, an output schema, and the relevant annotations, the description is complete enough for an agent to call the tool correctly. It explains the main caveat of creating a checkout link, when it errors, and that the resulting URL is for a human to complete, leaving no critical runtime surprise unexplained.

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 description does not elaborate on the parameters themselves, but the input schema fully documents both slug and product, including the product enum and pointer to list_offers. Since schema description coverage is 100%, the description adds no additional parameter semantics; the schema carries that weight.

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 and resource: creating a Stripe checkout URL for one paid add-on on one listing. It also clarifies the intended recipient is a human, which distinguishes this tool from purchase-completion or listing-management siblings.

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 clearly conveys when the tool is appropriate: whenever a checkout link for a paid add-on is needed before a human completes payment. It also gives important negative context by stating that this is not a completed purchase and will error in non-purchasable cases. It does not explicitly route the agent to sibling tools or name alternatives, though the schema pointing to list_offers partially fills that gap.

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