List Reseller Users

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context the annotations cannot express: the required credential mode and the meaning of a 403. It says nothing about result volume or ordering for large reseller accounts, which is the remaining gap.

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 short sentences: what it returns, then credential requirement, then error interpretation. The resource and scope are front-loaded with no filler or restatement of the title.

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 zero-parameter read tool with full annotation coverage and an output schema, the only things an agent needs beyond the schema are the auth mode and the failure meaning, both of which are stated. Nothing required for a correct first call is missing.

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?

There are zero parameters, so the baseline is 4; the schema has nothing for the description to clarify. The description correctly adds no parameter chatter and instead spends its words on authentication scope.

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 uses a specific verb and resource ('Lists the usernames of all users under the reseller account') and scopes the result to usernames only, which separates it from mailbox-listing siblings like list_email_accounts. It stops short of naming the closest sibling (get_reseller_user) as the single-user alternative, so differentiation is implied rather than explicit.

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 an explicit precondition (call while authenticated as the plain reseller username) and an explicit when-not (not while impersonating a user), plus a diagnostic for the 403 case. That is strong context, though it never names an alternative tool for retrieving a single user's details.

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