Declare what the order says should ship

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

No annotations are provided, so the description carries the full burden. It clearly discloses that the tool writes to a packing list ('Add an ordered line') and defines the source of truth ('what the order says is stated here'). But it does not mention whether the operation is reversible, how duplicates are handled/deduplication, effects on existing lines, or any status/lifecycle constraints. Some transparency is present, but much behavior is left undisclosed.

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 two sentences with no filler. It front-loads the core action ('Add an ordered line to a packing list') and packs useful scope clarification into the second sentence. Every clause earns its place. A slight deduction for the poetic phrasing 'so the shortfall is real' which carries a bit of style over function, but it still communicates the outcome.

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 schema covers all parameters at 100%, and the description conveys the action and scope. However, the tool has no output schema and no annotations, so the description could be its own system for the return behavior, effects on existing lines, and error cases. It is functionally sufficient but leaves key contextual gaps.

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 each parameter already has explicit descriptions (e.g., matching on SKU vs description, packing list id examples). The description only adds the phrase 'a SKU, a description and a quantity' which reiterates the required parameters. It does not add meaningful semantics beyond the schema, so baseline 3 is appropriate.

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 an ordered line to a packing list'. It also defines the exact payload (SKU, description, quantity) and clearly distinguishes this from reading tools by saying 'Nothing is read from the quotes, work order or invoice store; what the order says is stated here.' The title 'Declare what the order says should ship' reinforces the distinct purpose among siblings.

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 description conveys when to use this tool: to declare the expected shipment contents on a packing list. It explicitly contrasts with reads ('Nothing is read from...'), and the sibling names make it distinct from pack_item/unpack_item (actual packing operations). However, it does not explicitly name a sibling alternative or provide a when-not-to rule, so it relies on inference.

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