Assign a new role to a user in your tailnet by specifying the user ID and the desired role, updating their permissions.
Update a user's role in the tailnet.
| Name | Required | Description | Default |
|---|---|---|---|
| role | Yes | The new role to assign | |
| userId | Yes | The user ID |
Changes observed during successful MCP inspections.
v0.13.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate idempotent, non-destructive mutation. Description adds no extra behavioral context beyond 'update'. Baseline score as annotations suffice.
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?
Single concise sentence with no redundancy. Efficiently conveys the tool's purpose.
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?
No output schema and no description of return value. Lacks explanation of side effects or response format, though simple mutation may not require it.
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 covers 100% of parameters with descriptions. Description does not add meaning beyond schema, so baseline 3 is appropriate.
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?
Clearly states 'update a user's role in the tailnet' with a specific verb and resource. Distinguishes from sibling tools like tailscale_get_user or tailscale_approve_user.
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?
No guidance on when to use this tool vs alternatives (e.g., approve_user, suspend_user). Lacks context for appropriate scenarios or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.