Retrieve a checkout session

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is fully covered structurally. The description adds no behavioral context of its own — nothing about error behavior for unknown ids, whether expired sessions are returned, or what state the session comes back in.

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?

It is one short sentence with no waste, so it is not verbose — but this is under-specification rather than earned conciseness. The single sentence adds no information beyond the title, so it does not justify its own length as a useful signal.

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 itself is simple (one id, rich annotations), but with no output schema the description is the only place to explain what a retrieved checkout session contains (status, line items, amount, expiration). It supplies none of that, leaving the agent unable to predict the response shape.

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?

There is a single required parameter with 100% schema coverage ('The object's id.'), so the schema already carries the parameter meaning. The description adds nothing on identifier format (e.g., cs_ prefix) or where to source the id, which is the baseline-3 outcome when the schema does the heavy lifting.

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 'Retrieve a checkout session' merely restates the tool name and title verbatim, adding no specificity about what a checkout session is or what retrieval returns. It does not distinguish this tool from siblings like retrieve_customer, retrieve_invoice, or retrieve_subscription, which follow the same pattern.

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 guidance on when to use this tool versus alternatives such as list_* or create_checkout_session. The id-only schema implies lookup-by-identifier, but the description never states preconditions, when-not-to-use, or how to obtain a valid id.

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