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

With readOnlyHint/destructiveHint/openWorldHint already declared, the description still adds real value: it discloses the return artifact (an external Shopify checkout link) and that 'nothing is charged in ChatGPT', which is exactly the side-effect information an agent needs before invoking. It does not cover failure modes or the per-line quantity cap, and the mention of an 'external' store sits in mild tension with openWorldHint=false, but the operational picture is largely complete.

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 short sentences, no filler, with the invocation condition front-loaded before the behavioral note and the exclusion. Every sentence carries a distinct piece of information.

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?

There is no output schema, but the description compensates by describing the return value (an external checkout link) and the charging behavior. Combined with the usage gating and domain exclusions, an agent has enough to call this correctly; only the line/quantity limits and error behavior are left implicit.

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 100% and the single nested 'lines' parameter is fully typed in the schema, so the baseline of 3 applies. The description adds no meaning beyond the schema - notably it never surfaces the quantity maximum of 5 per line or the 4-line cap, which are the constraints most likely to cause a failed call.

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 states a concrete outcome - 'Returns an external Shopify checkout link on JAWD's store' - which is the specific result of building a cart, and the trigger condition ('after the user picks a product and quantity and asks to buy') cleanly separates it from get_product, search_products, and recommend_routine. An agent can identify what this tool produces without opening the schema.

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?

Explicit when-to-use ('only after the user picks a product and quantity and asks to buy') and explicit when-not-to-use ('Do not use for medical jaw pain, TMJ, orthodontic, or dental questions'). Siblings are not named by name, but the positive trigger and the negative domain exclusions are strong enough to route the agent correctly.

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