# Unity Asset Store and Unreal Fab for AI Agents: Your Asset Library, One Prompt Away

AI agents can now find packs you own on the Unity Asset Store and on Fab, import them into your project and build scenes from them.

_Last updated: 2026-11-11_

Most game developers own far more assets than they use. Over the years the Unity Asset Store and Fab libraries fill up with characters, props, interiors and effects bought on sale or added for free, and then they sit there because finding the right pack, importing it and checking what is inside takes an evening. The latest AI Game Developer release closes that gap: an AI agent can now search the asset library you already own on the Unity Asset Store and on Fab, import a pack into your project, read what came in and use it in a scene, all from one prompt.

[Media: Unity: three packs from the user's Asset Store account in one scene, staged by an AI agent through Unity-MCP]

## Why an Asset Store Integration for AI Agents

An AI agent in your editor is only as good as the material it can work with. Without access to your asset libraries it builds scenes out of cubes and primitives, or it asks you to download and import packs by hand and tell it the paths. With the new integration the agent sees the same library you see in the Package Manager or in the Fab panel, picks what fits the task, and brings it into the project itself.

Two things stay in your hands. The agent only works with packs your account already owns: buying a pack or adding a free one to your library still happens on the store website. And every import that the engine asks you to confirm is still confirmed by you.

## Unity Asset Store: Two Tools

Unity-MCP gets two new tools, mirroring the Fab ones below. assetstore-library lists every package in your My Assets library, merged with the packages already downloaded to the local Asset Store cache, filtered by words in the name, publisher or category. For each package the agent sees whether it is downloaded and whether it is already in the project. assetstore-add imports a package by its product id and answers with what arrived: the prefab, material, scene and model paths, the number of scripts, and notes the agent needs before using it, such as a pack made for URP in a project that renders with the Built-in pipeline.

```json
{ "tool": "assetstore-library", "input": { "query": "chess" } }
{ "tool": "assetstore-add", "input": { "package": "70092" } }
```

For the rarer steps the same data is available through RQL, the query language the agent already uses to read and change the editor: the assetStore source can read the table of contents of a .unitypackage without unpacking it (so the agent knows which prefabs a pack holds before importing it), import a nested package file, and start signing in to Unity. On a 500 MB interior pack, reading its contents takes under two seconds.

```bash
assetStore | get packages | where name contains "Interior" | call Contents(".prefab", 20)
```

The Unity account matters here. My Assets is read with the Unity account the editor is signed in to, so the editor has to be signed in. unity-mcp-cli now opens projects the way Unity Hub does, which gives the editor your Hub session, and a new unity-account command shows whether the editor is signed in and starts signing in when it is not. The agent has the same option with assetStore | call SignIn().

```bash
unity-mcp-cli unity-account ./MyGame
unity-mcp-cli unity-account ./MyGame --sign-in
```

Packs often ship more than one variant. The interior pack in the picture above is made for URP and carries its own Built-in conversion package inside; assetstore-add points that out, and the agent applies it with one more call, so the project renders the pack correctly instead of in magenta.

```bash
assetStore | call ImportFile("Assets/ithappy/Interior_Realistic/Render_Pipeline_Convert/Unity_6_Built-In_source.unitypackage")
```

Unity 6.6 checks package signatures on import, and packages from the Asset Store do not carry one yet, so the editor shows a Missing signature window for every pack. The agent never answers that window for you. assetstore-add returns at once, the agent tells you that Unity is waiting for your confirmation, and after you press Import Anyway it checks that the package arrived and continues.

## Unreal Engine and Fab

Unreal-MCP gets the same ability for Fab, Epic's marketplace. Three tools cover the flow. fab-search searches the public fab.com catalog by text, listing type, free-only and sort order. fab-library lists the items your account owns and says where each one is already imported. fab-add downloads an owned item and imports it through the engine's built-in Fab plugin, the same path the Fab panel's Add to Project button takes: Unreal Engine packs land under the project's Content folder, and glTF and FBX models and Megascans go through the same importers.

Fab uses the Epic account of the editor's Fab plugin. In a new editor session the first call opens Epic's login page in the browser (or the user clicks Fab in the editor toolbar); after signing in once the agent works on its own for the rest of the session. Complete projects and code plugins are still installed from the Epic Games Launcher.

[Media: Unreal Engine: Fantasy Interior Environment and Houseplant Pack from the user's Fab library, placed and lit by the agent]

## What We Saw in Live Tests

We tested both integrations the way a user would: a real agent, only the engine's MCP tools, and a plain prompt. The model was DeepSeek V4.1 Flash, a fast and inexpensive model, on purpose: if the tools are clear enough for it, they are clear enough for any agent.

In Unity the prompt asked for a chessboard with pieces and a human character from the user's Asset Store account, a new scene with every piece on its starting square, light, a camera and a screenshot. The agent, at that point with only the RQL source, found it through rql-schema, picked Chess Pieces & Board and Human Character Dummy out of 177 owned packages, imported both, worked out the board's square grid from the mesh, placed all 32 pieces correctly, saved the scene and rendered the shot. The only human steps were the two Import Anyway confirmations.

[Media: Unity: the chess scene the test agent built from Chess Pieces & Board and Human Character Dummy]

That first test also showed the weak spot. An RQL source has to be discovered: the agent must think of asking rql-schema what sources exist. So we measured both shapes with the same prompt, three runs each. With the two tools the agent went from the prompt to a started import in 4 or 5 calls and about 45 thousand tokens, every time. With the RQL source alone it found the feature in one run of three; in the other two it wrote its own import code, at 48 to 58 calls and up to 2 million tokens. The Unreal team saw the same on Fab, so both engines ship tools for the main flow. The same measurement moved Unity's Package Manager tools out of hiding: shown by default, they took an agent 5 to 9 calls to install a package instead of 12 to 17.

In Unreal Engine the agent read the user's Fab library of 55 items, imported Fantasy Interior Environment with its 852 assets, combined it with Houseplant Pack, used the pack's wood floor material, built and lit a room and saved the level. Only two of its calls touched Fab; everything else was ordinary scene work. In a narrower test, finding a houseplant pack in the library and adding it took three tool calls and about 27 seconds end to end.

## How to Try It

The Asset Store and Fab integrations are available now in Unity-MCP 1.11.0 and Unreal-MCP 0.31.0. They work in Claude Code, Cursor, VS Code Copilot and any other MCP client, because the abilities live in the engine plugins themselves, and the AI Game Developer App brings the new plugin versions with its next update. If you are new to AI Game Developer, start with the app from ai-game.dev/download and connect your engine as described at ai-game.dev/engines/unity or ai-game.dev/engines/unreal.

Then ask for something you would otherwise spend an evening on: a dressed room from your interior packs, a test level built from a modular kit, a showcase of a character pack. The agent will look in the library you already own first.

[Media: Unity: DropShip R35 from the user's Asset Store account]

## Related

- AI Game Developer for Unity: https://ai-game.dev/engines/unity
- AI Game Developer for Unreal Engine: https://ai-game.dev/engines/unreal
- RQL query language: https://ai-game.dev/docs/rql
- Unity tools catalog: https://ai-game.dev/docs/tools/unity
- Download the app: https://ai-game.dev/download

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