create_checkout_session

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

With no annotations, the description carries the full burden and does reasonably well: it discloses single-use ("one-time"), expiry, and the returned artifacts (token, hosted url, embed url), which is meaningful given there is no output schema. It omits auth/credential requirements, rate limits, and what to do with the token after issuance.

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?

Three tight sentences, zero filler, front-loaded with the core verb+resource before appending return values and the framework analogy. Every sentence earns its place.

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 description compensates for the absent output schema by enumerating return values, which is genuinely useful. However, for an 8-parameter mutation tool with no annotations, it leaves the recurring/subscription parameters and auth surface entirely unexplained, so it is only minimally complete.

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 coverage is only 63%, and the description adds no parameter-level meaning at all — not even for undocumented fields such as the bare `description`, `recurring_interval`, or `recurring_interval_days`. The subscription path (`is_recurring`, `recurring_interval*`) is never explained in prose, so the description fails to compensate for the coverage gap.

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?

"Mint a one-time, expiring Ultraner checkout token" gives a specific verb and resource, and the Stripe checkout.sessions.create analogy pins down the concept precisely. It still does not explicitly distinguish this unified hosted-checkout tool from siblings like create_stripe_session, create_paypal_order or create_mobile_money_payment.

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?

Usage is only implied: the description conveys that the payer selects the method on a hosted page, which hints at a hosted-flow scenario, but it never states when to choose this over the direct create_*_payment siblings or what prerequisites exist. An agent must infer the routing decision.

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