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matt-coppinger

Horizon MCP Server

list_vm_templates

Retrieve VM templates from a vCenter to use as base images for full-clone or linked-clone desktop pools, providing template IDs for pool provisioning.

Instructions

List VM templates available in vCenter for use as pool base images.

Templates are used for full-clone or linked-clone desktop pools (source=FULL_CLONE or LINKED_CLONE). Use the template_id in create_desktop_pool provisioning_settings instead of parent_vm_id.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
vcenter_idYesvCenter ID — obtain from list_virtual_centers
datacenter_idNoDatacenter ID — obtain from list_datacenters (optional)

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A4/5.0
Behavior3/5

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

No annotations are present, so the description carries the burden. 'List' implies a read operation IA and the vCenter scope is stated, but there is no mention of authentication, pagination, or what happens with an invalid vcenter_id. The added context about template_id usage is useful but not strictly behavioral.

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 tight, front-loaded sentences. The main action is stated first, then scope, then integration guidance. No redundancy or 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 simple read-only list with 2 params and a known output schema, the description covers purpose, scope, and downstream usage. It does not mention an explicit alternative (e.g., list_base_vm_snapshots), but that is not necessary for completion given the low complexity.

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 coverage is 100% — both parameters are already described with provenance hints ('obtain from list_virtual_centers' / 'obtain from list_datacenters'). The description adds no parameter-level meaning, but the schema already carries the load.

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 first sentence uses a specific verb and resource ('List VM templates available in vCenter') and immediately states the use case: templates for full-clone or linked-clone pools. No ambiguity about what this tool returns.

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?

Explicitly explains when the output is relevant (full-clone/linked-clone pools) and how to consume it (pass template_id to create_desktop_pool instead of parent_vm_id). Does not contrast with list_base_vm_snapshots or similar tools, but that is a minor gap.

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