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

Annotations already declare readOnlyHint=true, and the description adds the tailnet scope and filtering options without contradicting annotations. It does not disclose pagination, return format, or auth requirements, but for a simple read-only list operation this is acceptable. The REST endpoint reference adds minor implementation detail.

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 two concise sentences: the first states the action and filters, the second provides the REST endpoint. Every word adds value, with no redundancy or filler.

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 no output schema, the description adequately conveys the tailnet scope, filtering capability, and REST endpoint. It does not explicitly state the return type (array of users), but 'list users' implies a list, and no complex behavior requires further explanation.

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% with all three parameters (type, role, status) already documented. The description's mention of 'filtered by type, role or status' only restates what the schema provides, adding no extra syntax or behavioral meaning beyond baseline.

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 states the tool's function: 'List users of the tailnet' with optional filtering by type, role, or status. This uses a specific verb and resource, and distinguishes it from sibling tools like tailscale_get_user (singular) and tailscale_list_devices.

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 provides clear context on when to use the tool: to list tailnet users, with optional filters. It does not explicitly mention alternatives or when not to use it (e.g., when needing a single user), but the purpose is unambiguous enough for simple list operations.

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