Horizon MCP Server

list_audit_events

Read-only

List Horizon administrative actions and system audit events to review changes, troubleshoot issues, and support compliance audits. Supports filtering and paginated fetch-all retrieval.

Instructions

List Horizon audit events (administrative actions and system events).

Useful for reviewing recent changes, troubleshooting, and compliance auditing.

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 to narrow results by event type, user, or time range
`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

A4.6/5.0

Behavior5/5

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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds critical pagination behavior: has_more semantics, next_page continuation, fetch_all auto-fetch limits (10 pages / 5000 items), and the truncated flag. It also warns never to treat has_more=true results as complete, which is exactly the kind of behavioral disclosure that prevents agent error.

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

Conciseness4/5

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

Front-loads the core action and then provides pagination guidance efficiently. The explicit return-field list is somewhat redundant because an output schema exists, but the pagination sentences are essential and well-integrated.

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?

Given the read-only annotations and an output schema, the description still supplies the key operational context an agent needs: use cases, return structure, pagination continuation, auto-fetch limits, and truncation warning. Nothing important for correct invocation appears to be missing.

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 description coverage is 100%, so the baseline is 3. The description goes beyond the schema by explaining how to use page=next_page, how fetch_all behaves, and why a filter is preferred when a subset is needed.

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?

States a specific verb and resource: list Horizon audit events, scoped to administrative actions and system events. The sibling tools do not include another audit-event lister, so the tool is clearly distinguishable.

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?

Gives clear context with review, troubleshooting, and compliance-auditing use cases. It does not explicitly state when not to use it or name alternative tools, so it falls short of full when/when-not routing guidance.

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

Deploy Server