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

Annotations already establish that this is a read-only, non-destructive, open-world operation. The description adds that only active drivers are returned and enumerates the returned fields, but it does not discuss pagination, result limits, authentication requirements, or ordering.

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 short and front-loads the key information: active drivers, returned fields, and the optional site filter. The trailing 'GetDrivers.' adds little and reads like an API operation name, but the overall text is efficient.

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 simple read-only list tool with one optional parameter and no output schema, the description is largely complete: it states what is returned and how filtering works. It could be improved with brief notes on ordering, pagination, or typical result size.

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 single site_id parameter is already fully documented in the schema. The description adds minor context by noting its optional nature and relevance to multi-site accounts, but largely restates 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 clearly identifies the resource and scope: every active driver, including id, code, name, and site. It is distinguishable from singular sibling tools like ecourier_get_driver by its all-drivers scope, though it does not explicitly name alternatives.

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 optional site filter is explained as being for multi-site accounts, which gives useful context for that parameter. However, there is no explicit guidance on when to use this list tool versus ecourier_get_driver or other driver-related siblings.

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