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

With no annotations, the description carries the full burden of behavioral disclosure. It explicitly states that the agent never completes payment (EU PSD2), the user must approve in a browser, the result includes a URL and publicId, and the session expires after 1 hour. This is highly transparent and prevents misinterpretation.

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 concise and well-structured, with the main action in the first sentence and critical behavioral details in the second. Every sentence adds value without unnecessary 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 tool's complexity (5 params, no output schema, no annotations), the description covers the essential return values (URL and publicId) and the expiry behavior. It could potentially explain error scenarios or what happens after payment, but the presence of sibling tools like get_order_status covers that gap. It is sufficiently complete for an agent to use it correctly.

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 high (80%), so the baseline is 3. The description does not add parameter-level semantics beyond the schema, but it does clarify the overall purpose (one track) and reservation. It doesn't compensate for the missing 'locale' description, but that parameter is an enum with defaults, so the gap is minor.

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 specific action ('Create a checkout for one track') and the resource involved. It distinguishes itself from sibling tools by focusing on creating a payment checkout rather than searching or retrieving data.

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 context about the checkout flow, including that the user must approve payment and that the session expires. It does not explicitly name alternatives or exclusion criteria, but the context effectively implies when this tool should be used (for initiating a purchase).

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