Mixar for Hermes Agent

Connect Hermes Agent to Mixar, the AI-native 3D editor built on Blender 5.2. With this plugin Hermes can build and edit 3D scenes, generate models, textures, rigs and animation with AI, render stills and turntables, and export game-ready assets for Unity, Unreal and Godot.

The plugin is a portable Agent Plugin package:

• mcp.json starts the MCP server that Mixar installs for the signed-in user, through bin/mixar-mcp (bin/mixar-mcp.cmd on Windows).
• skills/mixar teaches Hermes the Mixar workflow: check readiness, read the scene, build in small steps, verify with a render, and deliver.
• plugin.json tells Hermes to offer the server only when Mixar 4.2.1 or newer is installed, and gives scene calls a 610-second tool-call timeout.

Requirements

• Mixar 4.2.1 or newer on macOS, Windows or Linux. Hermes refuses the install when it cannot find it (see Platforms for where it looks).
• A Mixar account, signed in in the app, with Connect MCP turned on. Both are done once in Mixar's interface.
• Hermes running on the same computer as Mixar. The launcher only reaches the Mixar app on its own computer, so a Hermes on a remote server or in a container cannot use this plugin.
• Hermes Agent v0.22.3 or newer.

Hermes supplies the model. You do not need a Mixar API key, a personal access token or a separate Python environment: the launcher runs on Mixar's embedded Python.

Install

From the Hermes plugin catalog:

hermes plugins install mixar

Or straight from GitHub:

hermes plugins install Mixar-AI/hermes-mixar --enable

Then in Mixar: sign in, open the profile menu > Connect MCP, and check that the status line reads "MCP is on". Run /reload-mcp in Hermes (or start a new session) and ask it to check Mixar's status. If no Mixar tools appear, ~/.hermes/logs/mcp-stderr.log says why.

The tools appear under the mixar server, for example mcp__mixar__scene_overview and mcp__mixar__execute_bpy_script. skills/mixar/references/setup.md covers first-run setup and troubleshooting.

What Hermes can do with it

Area	Tools
Read the scene	scene_overview, scene_hierarchy, get_object_details, inspect_geometry
Build	execute_bpy_script, move_groups, place_camera
AI generation	get_generation_params, enqueue_generation, get_all_queue_status (3D models, retopology, UV, rigs, animation, textures, images, video, splat worlds)
Assets and materials	search_asset_library, list_terrain_assets, create_layered_material
Verify	render_viewport, view_image, inspect_uv_map, inspect_mesh_seams
Deliver	export_scene (unreal, unity, godot, web, ar and print presets), export_asset, render_scene_image, render_scene_video
Scene tabs	mixar_scene_new, mixar_scenes, mixar_scene_switch, mixar_projects, mixar_project_open
Account	mixar_status, mixar_credit_balance, mixar_tool_quote, mixar_guide

The live list comes from the running Mixar and can grow between releases.

Disclosure

Read this before installing.

• Runs code from the installed Mixar app. bin/mixar-mcp executes ~/.mixar/connector/mixar-mcp (on Windows, bin/mixar-mcp.cmd runs %USERPROFILE%\.mixar\connector\mixar-mcp.cmd), a launcher the Mixar desktop app writes for the current user, which runs Mixar's bundled mcp.py on Mixar's embedded Python. The plugin ships no binary and downloads nothing.
• Arbitrary Python inside Mixar. execute_bpy_script and other scene tools run Python in the Mixar process with your privileges. A loopback connection is not a sandbox.
• Can start Mixar. A tool call made while Mixar is closed may open the installed Mixar app. Listing tools never does.
• Mixar stays open. If a tool call opened Mixar, it keeps running after Hermes exits; quit it like any other app.
• Network calls through Mixar. The launcher talks to the desktop app over loopback with a per-launch bearer token. The desktop app forwards calls to Mixar's backend (api.mixar.app) under your signed-in account.
• Prompts and images go to AI providers. For a generation, Mixar's backend passes the prompt, reference images and relevant scene context to the AI provider that runs the chosen model (such as OpenAI, Anthropic, Google, fal.ai, Replicate or Tripo). Mixar does not use them to train AI models.
• Diagnostic records. Mixar's backend records each MCP tool call (its inputs, including prompts, and its results) for troubleshooting and service improvement. It deletes these records within 30 days of collection and their backup copies within 7 days. This is separate from Share Usage Data.
• Spends Mixar credits. AI generation jobs and create_layered_material cost Mixar credits from your account; every other tool is free. mixar_tool_quote gives the current price before a call. The plugin declares these credit ranges to Hermes, which names the cost in its approval prompts and asks for an explicit yes before a chat passes 500 Mixar credits (it counts each call at the top of its range).
• No stored credentials. The plugin and the launcher never hold your Mixar token; the desktop app attaches its own login to each call.
• Reads outside the plugin. The launcher reads ~/.mixar/ (its manifest, the saved tool list and the discovery records of running Mixar apps).
• Usage data. The plugin sends none. Mixar's own desktop usage analytics are on by default, exclude prompts, file names and scene content, and can be turned off under Edit → Preferences → System → Privacy → Share Usage Data.
• Developer override. If MIXAR_MCP_LAUNCHER is set (in your shell or the Hermes .env), the plugin runs the program it names instead of Mixar's launcher. Leave it unset unless you are testing a Mixar build.
• No self-update. Updates arrive only as a new pinned commit in the Hermes plugin catalog. Mixar itself updates through its own updater, outside this plugin.

Full details are in the Mixar Privacy Policy.

Platforms

Platform	Where Hermes looks for Mixar	Version check	Launcher the plugin starts
macOS	Mixar.app in /Applications or ~/Applications	the app's Info.plist	~/.mixar/connector/mixar-mcp
Windows	the Mixar entry in installed apps (mixar.exe in its install folder), or %ProgramFiles%\Mixar\mixar.exe	the installed-apps entry	%USERPROFILE%\.mixar\connector\mixar-mcp.cmd
Linux	a mixar command on PATH, or the launcher Mixar writes on first run	none (presence only)	~/.mixar/connector/mixar-mcp

mcp.json holds one command, ./bin/mixar-mcp. On macOS and Linux it is the POSIX shell script; on Windows the MCP SDK Hermes uses resolves the same command through PATHEXT to bin/mixar-mcp.cmd. Mixar for Linux is a portable archive with no fixed install folder, so open Mixar once before installing the plugin, or put its mixar executable on your PATH.

Development

hermes plugins validate /path/to/hermes-mixar --install-deps
hermes plugins doctor /path/to/hermes-mixar

The Launcher shim workflow (.github/workflows/launcher-shim.yml) starts bin/mixar-mcp the way Hermes does against a stub Mixar launcher on macOS, Windows and Ubuntu runners.

Two optional variables point the package at a development or QA build of Mixar. Set them in your shell or the Hermes profile's .env:

• MIXAR_MCP_LAUNCHER: another launcher, for example a source build's.
• MIXAR_MCP_DISCOVERY_DIR: another discovery folder for running Mixar apps.

VERIFICATION.md records what has been checked and what has not.

License

MIT. See LICENSE. Mixar itself is a separate product under its own license.