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

Annotations already declare the operation as read-only and non-destructive, so the description does not need to repeat that. It adds meaningful behavioral context beyond annotations: there is no row limit, and partner users are restricted to their own scope.

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 definition is two efficient sentences with no wasted language. The purpose and the key scope restriction are front-loaded.

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 aggregation tool with five fully documented optional parameters and no output schema, the description gives enough to call it correctly. It could more explicitly describe the aggregation output shape, but the core return semantics are stated.

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 all five optional parameters are already well documented. The description adds a grouping notion (“by carrier and user”) but does not clarify parameter behavior beyond what the schema provides.

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 output type: return aggregated shipment counts and totals by carrier and user. This clearly distinguishes it from list/search tools, though it does not explicitly differentiate it from overlapping siblings like PartnerSummary or GetAnalytics.

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 provides a useful scope constraint — partners see only their own partner scope — but does not say when to use this tool versus alternatives such as PartnerSummary or GetAnalytics. Usage is implied by the aggregation purpose rather than explicitly guided.

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