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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds meaningful behavior beyond that: the chargeable-weight rule and the explicit 'null, never a guess' policy for cartons without dimensions, which is valuable edge-case transparency.

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?

Two compact sentences with no filler. The scope is front-loaded, and the crucial null-handling edge case is stated explicitly rather than buried.

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?

For a read-only reporting tool with two inputs and no output schema, the description covers the computed fields and the key edge case well. It could be slightly more complete with an example or rounding/divisor effect note, but the schema already covers divisor.

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 packing_list and divisor are already documented. The description adds no parameter-level detail beyond what the schema provides; the formula it gives concerns output semantics rather than input 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 clearly states what the tool reports: per-carton and per-shipment weight metrics including tare, net, gross, volume, volumetric weight, and chargeable weight. This is a specific calculation/report purpose, though it does not explicitly contrast itself with sibling tools like packing_list_show or packing_slip.

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 gives no when-to-use guidance, prerequisites, or exclusions. It does not mention when to prefer carton_report over related packing/reporting siblings, leaving the agent to infer usage solely from the metric list.

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