Horizon MCP Server

assign_machine_users

Assign or unassign Active Directory users to a dedicated desktop machine, with one user per machine in most pool configurations.

Instructions

Assign or unassign users to a dedicated desktop machine.

Only applicable to machines in dedicated (non-floating) desktop pools. A machine can only have one assigned user at a time in most pool configurations.

Input Schema

TableJSON Schema

Name	Required	Description
`action`	Yes	assign: assign users to this dedicated desktop. unassign: remove existing user assignment.
`user_ids`	Yes	AD user IDs to assign or unassign. Use search_ad_users_or_groups to find IDs.
`machine_id`	Yes	Machine ID — obtain from list_machines

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 10, 2026

TDQS

A4/5.0

Behavior3/5

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

With no annotations provided, the description carries the full disclosure burden. It adds useful behavioral context: the tool only works on dedicated pools and a machine can hold only one assigned user in most configurations. However, it does not mention permission requirements, what happens when a machine already has a user, or whether unassigning a nonexistent assignment is an error.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences with no filler. The core action is front-loaded, and the critical constraints follow economically. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the essential operational constraints: dedicated-pool applicability and the one-user-per-machine limitation. Since an output schema is present, return-value documentation is not needed. Minor gaps remain around failure behavior on conflict, but the description is sufficient for correct invocation in typical cases.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and each parameter, including the action enum values, is documented in the input schema. The description adds machine-context but no additional parameter-level meaning beyond the schema, matching the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a clear verb-resource pair: 'Assign or unassign users to a dedicated desktop machine.' It also distinguishes the tool from pool-level entitlement tools by emphasizing 'machine' and 'dedicated (non-floating) desktop pools,' making its scope immediately recognizable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly limits applicability to machines in dedicated non-floating desktop pools, which tells an agent when NOT to use this tool. It does not name an alternative tool for pool-level assignments, but the exclusion is clear enough to guide selection.

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

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