unity-mcp v10 AI Asset Generation: Bring Your Own Provider Keys, Pay Each Provider

The unity-mcp v10 AI asset generation feature is a bring-your-own-key toolset. It is switched off by default. Once you turn it on, an AI agent connected to the Unity Editor can generate 3D models and 2D images through third-party providers, or import existing models, and place the results in your project. You supply an API key for each provider and pay that provider directly. The project does not resell credits.

This note compares three primary sources: the v10.0.0 release page, PR #1218, which added the feature, and the v10 migration notes. Each claim below comes from one of those documents or from the project README.

What does v10.0.0 add, in short?

According to the release page, v10.0.0 was published on 30 June. Its headline changelog entry is "AI Asset Generation, 3D gen/import + 2D image (BYO-key)", contributed by Scriptwonder in PR #1218. The same release lists a revamp of the docs, branding, distribution and analytics (#1222), plus the version bump. The full changelog compares v9.7.3 to v10.0.0.

The migration notes say the tool surface has grown from 29 entrypoints at the v9.0.0 baseline to 47 entrypoints across 10 groups. The new asset_gen group is the main addition.

The project now goes by MCP for Unity. The repository README describes it as a bridge between AI assistants and the Unity Editor. If you have not connected a client yet, start with our Unity MCP setup guide for Claude Code or Cursor. The asset tools only matter once that connection works.

What do the four asset_gen tools do?

The migration notes describe four tools:

The migration notes say generation jobs are asynchronous. A request returns a job_id, and the client then polls with action=status until the job completes or fails. That design means an agent makes several calls for each asset. A slow provider should show up as a longer polling loop, not as a timeout on the first call.

According to the PR description, results are imported into Assets/Generated/. The PR also says generation runs only through MCP or the CLI. The Asset Gen tab in the Editor is for configuration only, so there is no button there to generate a model.

Which keys do you need, and who bills you?

Every provider is bring-your-own-key

The migration notes are direct about this. v10 has no bundled credits and no hosted asset-generation credits. Each provider's pricing, rate limits and content policies apply to your requests. Hosted credits appear on the notes' list of things not included in v10.

So you need one account for each provider you plan to use:

• 3D generation: a Tripo or Meshy account
• 2D images: a fal.ai or OpenRouter account
• Model search and import: Sketchfab access for import_model
• Local files: no provider needed

None of the release page, the PR or the migration notes gives prices. Check the current pricing, rate limits and licence terms on the Tripo, Meshy, fal.ai, OpenRouter and Sketchfab sites before you enable anything. Those terms can change without any update to MCP for Unity.

Where the keys are stored

You enter keys in the Unity Editor's Asset Gen tab. According to the PR and migration notes, the keys are stored in the operating system's secure store:

• macOS: Keychain
• Windows: Credential Manager
• Linux: libsecret

The PR also describes an encrypted fallback using AES-256-CBC with HMAC for systems where the OS store is not available.

The docs say keys are not written to EditorPrefs, project assets, logs or MCP tool parameters. The PR says keys "never cross the bridge". This means the MCP client (Claude Code, Cursor or another agent) never receives the key, and the Unity side attaches it when it calls the provider. So don't paste provider keys into your MCP client's config file. The design doesn't need them there, and putting them there defeats the separation.

The agent decides when to spend

The Unity side holds the keys, but the agent decides when to call a paid tool. Once asset_gen is active, a loose prompt such as "add some props to this scene" could start several billed generation jobs. Neither source describes a spending cap inside MCP for Unity. That leaves two spend controls: the opt-in group itself, and any limits you set in each provider's dashboard. Keep the group off when you aren't generating assets, and set provider-side caps where they exist.

How do you turn on asset_gen?

The migration notes give the steps:

1. Update the package. Pin v10.0.0 to get this exact release, or track main, which the notes describe as the latest stable release.
2. Check your Unity version. The notes list Unity 2021.3 LTS as the minimum version and say Unity 6.x is supported.
3. Install glTFast if you need GLB or glTF. GLB and glTF import depend on the glTFast package. You can install it from the Dependencies tab or the Package Manager. FBX import doesn't need it.
4. Add provider keys in the Asset Gen tab of the Editor window.
5. Activate the group from your agent:

manage_tools action=activate group=asset_gen

6. Refresh if the tools don't appear. The troubleshooting section says some clients cache tool lists. If the four tools are missing after activation, refresh or reconnect the MCP server.

If GLB models fail to import, the docs point first to the missing glTFast dependency from step 3.

What are the limits and open caveats?

Input modes differ by provider

The PR and migration notes say providers handle image inputs differently:

• Meshy image-to-3D and fal.ai/OpenRouter image-to-image accept a local image_path. The file is sent inline as a base64 data URI.
• Tripo image-to-3D needs a hosted image_url. Passing a local file returns an error.

If your concept art is only on disk, use Meshy for image-to-3D or upload the image somewhere Tripo can reach it.

Live testing status is unclear

The PR description reports 1306 passing Python tests and EditMode results of 968 of 1014. It says unit tests cover request shaping using a fake transport. The same text, written while the PR was still a draft, says live smoke tests with real keys for each provider were still pending. It names Meshy refine, the fal /edit path and the local image_path paths as not yet verified live. The release page doesn't say whether those checks were done before v10.0.0 shipped. Treat those paths as unconfirmed until the maintainers say otherwise.

Other documented limits

• Transparency: the PR says transparent is only an import flag, because fal's FLUX models can't generate transparent backgrounds.
• Provider coverage: the migration notes say not every provider is guaranteed to support every input mode.
• Quality: the notes don't promise that generated assets are production-ready without an artist's review.
• Repo size: the notes advise reviewing large binary output before you commit it. Generated meshes and textures can bloat a repository quickly.

Security hardening

The PR describes two protections. First, archive extraction is limited to an allowlist of inert model and texture file types, so a provider's zip can't drop a .cs script or a .dll into your project. Second, download URLs are restricted to http(s). These defaults make sense for a feature that writes third-party files into an editor that compiles code automatically.

Can MCP for Unity work with Blender?

Only through files. The migration notes say import_model_file lets BlenderMCP or any other modelling workflow export a file that Unity then imports and places. The notes state that MCP for Unity does not control Blender directly and does not configure BlenderMCP automatically.

So the handoff works like this. One agent (or a person) works in Blender and exports an FBX, OBJ or glTF file, and an agent on the Unity side picks it up. For an example of AI-driven Blender modelling that could feed this handoff, see our specimen on 3D-Agent, a Blender addon where the AI writes Blender Python for low-poly assets. More Blender coverage is under /tags/blender.

Verdict: who should enable it?

This assessment draws on what the release page, PR and docs say the tools do and don't cover.

Worth switching on if:

• You are prototyping or making a jam game and want placeholder 3D models or concept images without leaving the Editor.
• You already have Tripo, Meshy, fal.ai or OpenRouter accounts with billing and limits set up, so you can see the extra cost.
• You want an agent to pull models from Sketchfab or bring in local Blender exports. These are the cheapest parts of the group, since local import calls no paid provider.

Probably not yet if:

• You need predictable costs. Spending depends on how often your agent calls the tools, and MCP for Unity has no bundled credit pool to cap it.
• You need a consistent art style or production-ready meshes. The docs themselves say an artist's review is needed.
• You rely on the paths the PR marked as not live-verified, such as Meshy refine or fal edits.

On licences: the notes don't cover licensing for Sketchfab models or generated assets. Check each Sketchfab model's licence and each provider's output terms before you ship anything.

For other ways to connect agents to Unity, compare Unity's own Claude Code plugin and Codex plugin, or browse /tags/coding-agents.