Horizon MCP Server

assign_machine_users

DestructiveIdempotent

Assign or unassign Active Directory users to a dedicated Horizon desktop machine, ensuring one assigned user per machine for non-floating pools.

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

A4.2/5.0

Behavior4/5

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

Annotations already declare destructiveHint=true, idempotentHint=true, and closed-world read/write status. The description adds useful behavioral context by disclosing pool eligibility and the one-user-per-machine constraint in most configurations.

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?

The description is three short sentences, front-loads the core action, and follows with two relevant constraints. Every sentence adds useful context with no filler.

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?

For a tool with rich annotations, complete parameter schema, and an output schema, the description is largely complete: it covers the action, eligibility, and cardinality caveat. It lacks only a pointer to alternatives or related tools, which is a minor gap.

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 the schema already explains action, user_ids, and machine_id in detail. The description adds no parameter-level meaning beyond what the schema provides, so baseline 3 is appropriate.

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 states a specific verb pair (assign/unassign) and resource (users to a dedicated desktop machine), and scopes it to dedicated non-floating pools. This clearly distinguishes it from sibling tools that manage machines, pools, or AD objects.

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?

It gives a clear applicability constraint: only dedicated (non-floating) desktop pools. It does not name an alternative tool or explicitly state when not to use it beyond that pool-type exclusion.

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

Deploy Server