List users

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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description redundantly states 'Read-only'. It does add useful context about email validity for the header, but it doesn't disclose additional behavioral traits such as pagination, result ordering, or whether the list is exhaustive, which would be valuable given openWorldHint.

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 concise sentences, front-loaded with the core action, followed by a specific use case. No wasted words; every phrase adds value.

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?

Given the tool's low complexity (zero parameters, no output schema), the description adequately covers purpose, usage, and safety profile. The annotations supply behavioral bounds, and the description supplies the practical context needed to select and invoke the tool.

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?

The tool has no parameters, so the schema covers 100% of the parameter surface. The description adds meaning beyond the empty schema by clarifying that the returned data contains valid emails needed for a specific header, which is the kind of semantic value expected for a zero-parameter tool.

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+resource pair ('List users') and clearly identifies the account scope. It also states a distinct downstream purpose (finding valid emails for the X-AuditUser header) that differentiates it from sibling list tools like list_smartlists.

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 explicitly tells when to use this tool: to find valid emails for the X-AuditUser header required on write operations. There are no exclusions or named alternatives, but this is clear, contextual guidance for a simple read-only listing operation.

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