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

The annotations already disclose that this is a write, destructive, non-idempotent, open-world operation. The description adds useful context that Order Desk recalculates totals after adding the item, but it does not explain response behavior, permissions, or duplicate handling.

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 a single tightly structured sentence that front-loads the write nature and core action. It contains no filler and includes the relevant endpoint.

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?

Given the rich annotations, full schema coverage, and lack of an output schema, the description is nearly complete for selecting and invoking the tool. It could be improved by noting what the response contains or how duplicate line items are handled.

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%, so the schema already documents the parameters thoroughly. The description only reiterates the order_id path and the fact that one item is added, without adding format or constraint details beyond the schema.

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 specific verb and resource: add one line item to an existing order. It clearly distinguishes this from creating an order or adding other order-related entities such as notes or shipments.

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?

The usage is implied by 'add one line item to an existing order,' but there is no explicit guidance on when to choose this tool versus alternatives like update_order or list_order_items. No exclusions or prerequisites are mentioned.

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