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

Annotations only say readOnlyHint=false, idempotentHint=false, destructiveHint=false; the description goes well beyond them: each call mints a new 7-day link usable on any device, the link reflects the basket state at open time, an empty basket returns an error, the assistant never sees payment details, and no order is placed until the customer pays on-site. That is exactly the behavioral context an agent needs before invoking a non-idempotent flow.

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?

Opens with the trigger, then the parameter rule, then the link lifecycle and on-site flow, closing with the sibling alternative. Every sentence carries distinct information (durability, error case, privacy boundary, order timing) with no repetition.

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?

An output schema exists so return values need no explanation, and the description still covers the gaps that matter: error behavior on an empty basket, the hand-off point where the customer authenticates and pays, and the privacy boundary. Complete for a single-parameter checkout-entry tool.

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 100% and the schema already documents basket_id, so the baseline is 3. The description earns above-baseline credit by explaining the decision rule behind the parameter (host-dependent identity) and by clarifying that the value comes from an earlier basket tool in the same conversation, adding rationale beyond the field description.

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?

Names a specific verb (go to checkout / make a link) and resource (the teas.co.uk basket) and states the trigger condition explicitly. It also distinguishes itself from the sibling checkout_session by naming it as the alternative for buying specific products without the basket.

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 an explicit when ('customer is ready to buy what is in their basket'), an explicit conditional for the single parameter (omit on hosts that identify the customer, otherwise pass the earlier basket_id), and routes to checkout_session for the case where no basket exists. Nothing is left to inference.

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