Horizon MCP Server

list_image_management

Read-only

List image management streams, versions, or tags. For versions and tags, first retrieve a stream ID from the streams list.

Instructions

List image management streams, versions, or tags.

Versions and tags belong to a stream, so Horizon requires a stream ID for them (verified live — omitting it returns 400 "im_stream_id parameter is missing"). List streams first, then pass a stream's id as stream_id.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`resource`	Yes	Image management resource to list: streams (publishing pipelines), versions (published images), tags (pool targets).
`stream_id`	No	Image stream ID — required for versions and tags. Obtain from resource='streams'.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.2.0Sep 30, 2026

addedInput schema / properties / stream_id

Added value: +{
+  "default": "",
+  "description": "Image stream ID — required for versions and tags. Obtain from resource='streams'.",
+  "type": "string"
+}

First observedv0.1.0Sep 10, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real value by disclosing the verified failure mode (omitting stream_id returns 400 'im_stream_id parameter is missing'), which is behavioral detail not present in the structured fields.

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?

Two sentences, zero filler, front-loaded with the resource list and followed by the dependency workflow. Every clause earns its place.

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?

An output schema exists, so return values need not be described. With annotations covering safety and the schema covering both params, the description supplies the only missing operational piece — the stream_id prerequisite and its error behavior.

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%; both parameters, including the enum values, are already documented in the schema. The description reinforces the stream_id dependency but adds no syntax/format detail beyond it, so baseline 3 applies.

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

Purpose4/5

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

States a specific verb (List) and resource (image management streams, versions, or tags), and enumerates the three listable resource types. It is clear what the tool returns, though it does not explicitly distinguish itself from any similarly-named sibling (none of which overlap in this domain).

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 explicit sequencing guidance: list streams first, then pass a stream's id as stream_id for versions/tags. It states the condition under which stream_id is required. No alternatives exist among siblings, so there is little else to route against.

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

Deploy Server