Happy Horse MCP Server

happyhorse_generate_video_from_image

Generate a video from a first-frame image by providing its public URL. Optionally add a motion prompt to control animation, and adjust duration, aspect ratio, resolution, and model.

Instructions

Animate a first-frame image with Happy Horse.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`seed`	No	Optional reproducibility seed.
`model`	No	Image-to-video model: happyhorse-1.0-i2v or happyhorse-1.1-i2v.	happyhorse-1.1-i2v
`ratio`	No	Output aspect ratio: 16:9, 9:16, 1:1, 4:3, or 3:4.	16:9
`prompt`	No	Optional motion and camera instructions for animating the image.
`duration`	No	Output duration in seconds, from 3 through 15.
`image_url`	Yes	Public URL of the image to use as the first frame.
`watermark`	No	Whether to add a Happy Horse watermark.
`resolution`	No	Output resolution: 720P or 1080P.	1080P
`callback_url`	No	Optional webhook URL. Omit it to receive a task ID for polling.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.1Aug 24, 2026

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

A3.6/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of explaining behavioral traits. It only says 'Animate' and gives no indication that this is likely an asynchronous task returning a task ID, whether an image URL must be publicly accessible, what the output object contains, or cost/side effects. This is a clear gap for a generation tool.

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, efficient sentence with zero filler. It communicates the core purpose in the fewest possible words, and there is no redundant content to trim.

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

Completeness2/5

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

This is a high-complexity tool with nine parameters, multiple sibling tools, and likely asynchronous behavior. The description is a single sentence that only states the primary purpose, leaving the agent to infer when to choose this tool over generate_video or generate_video_from_references, and how to handle job submission and polling. The 100% schema coverage and existence of an output schema mitigate missing return-value details but do not compensate for lack of usage and workflow context.

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%, and all nine parameters already have individual descriptions with defaults, ranges, enums, and guidance. The tool description itself adds nothing new to the parameter semantics, so the baseline of 3 is appropriate.

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 ('Animate') and a specific resource ('first-frame image'), making it clear this is an image-to-video generation tool. The phrase 'first-frame image' differentiates it from sibling tools like generate_video (presumably text-to-video), edit_video, and generate_video_from_references.

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?

The description clearly implies usage: it should be used when you have a first-frame image to animate with Happy Horse. There is no explicit statement about when not to use it or which sibling tool to prefer, but the context of animating a first-frame image is clear enough without exclusions.

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

Deploy Server