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

With no annotations, the description carries the full burden and does reasonably well: it discloses a side effect ('writes LabelLog entries'), the return payload ('JSON request/response bodies'), and a hard precondition (carrier contract + product selected in the Shipping snapshot). It omits auth/permission requirements and whether the live call incurs cost or rate limits.

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 sentences, front-loaded with what the tool does, then return/side-effect behavior, then the prerequisite. No filler; each sentence carries distinct 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?

For a side-effecting, no-annotation tool with no output schema, it covers purpose, precondition, return shape, and side effects. The remaining gap is auth/permission expectations and failure behavior, which is minor but non-trivial for a live external carrier call.

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 three parameters are already fully documented in the schema. The description only references the draft ID conceptually and adds no format or intentId semantics beyond what the schema provides. Baseline 3 applies.

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: 'Call the carrier live rates API for a user's shipment draft'. It is clearly distinguishable from data-listing siblings, though it does not explicitly name a contrasting sibling. The parenthetical precondition sharpens the scope further.

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 gives a clear prerequisite workflow: 'Use GetShipmentDraftsForUser and GetShipmentDraft first to find the draft ID', naming the alternatives to run beforehand. It stops short of stating when NOT to use it versus a non-debug rate lookup, so not a full 5.

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