Horizon MCP Server

list_application_pools

Read-only

Retrieve published application pools from Horizon, with paging controls to fetch all pages or narrow results when more items remain.

Instructions

List published application pools in the environment.

Returns {items, count, page, size, pages_fetched, has_more, next_page, truncated}. If has_more is true there may be more results: call again with page=next_page (or narrow the filter), or pass fetch_all=true to fetch pages automatically (stops after 10 pages or 5000 items and sets truncated=true). Never treat a result with has_more=true as the complete list.

Input Schema

TableJSON Schema

Name	Required	Description
`page`	No	Page number (1-based)
`size`	No	Results per page (max 1000)
`filter`	No	Horizon filter JSON string
`fetch_all`	No	Fetch successive pages automatically (up to 10 pages / 5000 items). Prefer a filter when you only need a subset.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed5 schema fields changedv0.2.0Sep 30, 2026

addedInput schema / properties / fetch_all

Added value: +{
+  "default": false,
+  "description": "Fetch successive pages automatically (up to 10 pages / 5000 items). Prefer a filter when you only need a subset.",
+  "type": "boolean"
+}

addedOutput schema / additionalProperties
```
Added value: +true
```

removedOutput schema / properties

Removed value: -{
-  "result": {
-    "items": {},
-    "type": "array"
-  }
-}

removedOutput schema / required
```
Removed value: -[
-  "result"
-]
```
removedOutput schema / x-fastmcp-wrap-result
```
Removed value: -true
```

First observedv0.1.0Sep 10, 2026

TDQS

A4.5/5.0

Behavior5/5

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

Beyond the read-only annotation, the description discloses the return shape, pagination behavior, automatic fetch limits (10 pages / 5000 items), and the critical warning that has_more=true means the result is not the complete list. This is rich operational context that helps an agent avoid incorrect assumptions.

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 front-loaded with the purpose, then efficiently covers return fields and pagination handling. Every sentence earns its place; there is no redundant or filler content.

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

Completeness5/5

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

For a read-only list tool with an output schema and annotations, this description is complete enough. It explains the key pagination semantics and the has_more warning, so an agent has all the context needed to call it correctly.

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

Parameters4/5

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

Schema coverage is 100%, so all parameters are already documented. The description still adds value by explaining fetch_all's automatic stopping limits and truncated flag, and by recommending a filter when only a subset is needed, going beyond the schema's basic definitions.

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 specific verb and resource: 'List published application pools in the environment.' It clearly distinguishes this plural list operation from single-item siblings like get_application_pool and from other list tools such as list_desktop_pools.

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

Usage Guidelines3/5

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

The description gives useful guidance for handling pagination and fetch_all, but it does not explicitly state when to choose this tool over alternatives like get_application_pool or list_desktop_pools. Usage is implied rather than contrasted with siblings.

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

Deploy Server