Happy Horse MCP Server

happyhorse_edit_video

Edit a video by describing changes in text and adding reference images. Set duration, ratio, resolution, and audio to generate the modified footage.

Instructions

Edit a source video using text and optional reference images.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`seed`	No	Optional reproducibility seed.
`model`	No	Video-edit model. Currently happyhorse-1.0-video-edit.	happyhorse-1.0-video-edit
`ratio`	No	Output aspect ratio: 16:9, 9:16, 1:1, 4:3, or 3:4.	16:9
`prompt`	Yes	Instructions describing the desired changes.
`duration`	No	Output duration in seconds, from 3 through 15.
`video_url`	Yes	Public URL of the source video to edit.
`watermark`	No	Whether to add a Happy Horse watermark.
`image_urls`	No	Optional style or subject reference images, up to five.
`resolution`	No	Output resolution: 720P or 1080P.	1080P
`callback_url`	No	Optional webhook URL. Omit it to receive a task ID for polling.
`audio_setting`	No	Audio policy: auto, or origin to preserve the source audio.	auto

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.1.1Aug 24, 2026

addedInput schema / properties / duration

Added value: +{
+  "default": 5,
+  "description": "Output duration in seconds, from 3 through 15.",
+  "maximum": 15,
+  "minimum": 3,
+  "title": "Duration",
+  "type": "integer"
+}

addedInput schema / properties / ratio

Added value: +{
+  "default": "16:9",
+  "description": "Output aspect ratio: 16:9, 9:16, 1:1, 4:3, or 3:4.",
+  "enum": [
+    "16:9",
+    "9:16",
+    "1:1",
+    "4:3",
+    "3:4"
+  ],
+  "title": "Ratio",
+  "type": "string"
+}

First observedv0.1.0Jul 13, 2026

TDQS

B3.3/5.0

Behavior2/5

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

With no annotations provided, the description carries the burden of behavioral disclosure, but it only names the operation. It does not mention asynchronous task handling, polling, webhook behavior, or any constraints on source video/editing. The schema hints at async behavior through callback_url, but the description itself adds no transparency.

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 a single, front-loaded sentence with no filler or repetition. Every phrase adds meaning: "edit", "source video", "text", and "optional reference images".

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

Completeness3/5

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

The tool has 11 parameters and no annotations, so the description is minimal. The complete parameter names and schemas compensate, as does the presence of an output schema, but the description omits usage and behavioral context. It is functional but not thorough for a video-editing tool with asynchronous implications.

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 descriptions cover 100% of parameters, so the baseline is 3. The description's mention of "text" and "optional reference images" does indirectly map to prompt and image_ulUrls, but it does not add meaningful detail beyond the schema.

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 uses a specific verb and resource: "Edit a source video using text and optional reference images." The word "edit" and "source video" directly distinguishes this from the generate_video family of siblings. It also informs the agent of the core input modalities (text and optional reference images).

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

Usage Guidelines2/5

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

No guidance is given about when to choose this tool over siblings such as generate_video_from_image or generate_video_from_references. The description only implies editing an existing video; it does not state explicit conditions, alternatives, or when not to use it.

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

Deploy Server