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

Annotations already establish that this is not read-only, is idempotent, and is not destructive. The description adds useful behavioral context: no charge occurs until complete_checkout, and the result includes delivery options and order total. It does not discuss authorization, rate limits, or retry behavior beyond the annotation and schema hints.

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 short and front-loads the purpose, then adds return and billing context. The final sentence, 'Delivered by JENNi,' repeats the opening phrase and could be removed, but overall it remains efficient.

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?

With an output schema and annotations already covering return shape and safety/idempotency traits, the description is largely complete for initiation. It explains the next step and the billing timing. The main remaining gap is that it does not disambiguate this tool from start_checkout.

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 only 40%, so the description needs to compensate. It identifies the three required top-level inputs (product_id, delivery_address, buyer/contact details), while quantity and idempotency_key are documented in the schema itself. Nested field details are left to the schema, but the description meaningfully frames the required parameters.

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 clear verb and resource: start/create an order/checkout. It does not distinguish this from the sibling start_checkout, so an agent cannot tell from the description alone which of those two initiation tools to use.

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?

It implies the workflow by saying nothing is charged until complete_checkout, which suggests this tool precedes that one. However, it gives no explicit when-to-use or when-not-to-use guidance, and it does not address the very similar start_checkout sibling.

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