Janction Render MCP Server

JANCTION Render

A cloud GPU render farm for Blender, built for AI agents. Render Blender scenes on JANCTION GPUs from Claude, ChatGPT, Claude Code, Codex, Cursor or any MCP client: an MCP server (remote and stdio) plus a CLI. Use it to render Blender without a GPU, or when rendering locally is slow.

• Input: a .blend file, or a bpy Python script that builds the scene (no local Blender needed).
• scene_info reads the scene without rendering (cameras, frame range, missing files).
• render_preview returns 1-4 low-cost frames tiled in one image within seconds, so the agent can look, fix, and repeat.
• render_estimate says how long a render will take ("about 3 minutes") and whether it fits today's free quota.
• render_final renders the frames on GPUs and joins them into an MP4; render_status reports the remaining time.
• Free beta: no charges. Each key gets 10 GPU-minutes per day; a final render is up to 240 frames at 1080p. Paid plans (per GPU second, prepaid credit) will be announced on the service page before they start.
• Inputs and results are deleted 24 hours after last use and are never used for training.

Status

Free beta. Service page: https://render.janction.jp (/v1/health, /llms.txt). Blender 5.0, Cycles on GPU.

Connect (remote MCP, nothing to install)

MCP server URL: https://render.janction.jp/mcp (Streamable HTTP). Auth is OAuth 2.1 with dynamic client registration: pressing "Connect" opens a page that creates a free API key (or takes one you already have). A raw API key also works as Authorization: Bearer jr_....

Remote tools take scene_script (bpy code as text), scene_url (an https link to a .blend or .py) or scene_id; results come back as an inline image plus download links that need no key and work for about 24 hours.

Claude Code plugin (the remote connector plus a skill with the workflow):

/plugin marketplace add JasmyLab-JANCTION/janction-render
/plugin install janction-render@janction-render

Install (stdio MCP, sends local files)

The package is on PyPI as janction-render.

# Claude Code (uvx runs it without a global install)
claude mcp add janction-render -e JANCTION_RENDER_SERVER=https://render.janction.jp -- uvx --from janction-render janction-render-mcp

# or with pip / pipx
pip install janction-render
claude mcp add janction-render -e JANCTION_RENDER_SERVER=https://render.janction.jp -- janction-render-mcp

Codex: add to ~/.codex/config.toml

[mcp_servers.janction-render]
command = "uvx"
args = ["--from", "janction-render", "janction-render-mcp"]
env = { JANCTION_RENDER_SERVER = "https://render.janction.jp" }

A temporary API key is issued automatically on first use and cached in ~/.janction-render.json; set JANCTION_RENDER_API_KEY to pin one (quota and, later, credit belong to the key). The same key can be used from the remote connector: paste it on the connect page.

Then, in Claude Code:

Build a small street scene in Blender with a camera fly-through and render a preview with janction-render.

Tools

CLI: janction-render inspect|preview|render|status|download|cancel|jobs|balance|topup|info.

Writing a scene script

import bpy, math
for ob in list(bpy.data.objects):
    bpy.data.objects.remove(ob, do_unlink=True)
scene = bpy.context.scene
scene.frame_start, scene.frame_end = 1, 24
bpy.ops.mesh.primitive_monkey_add(location=(0, 0, 1))
cam = bpy.data.objects.new("Camera", bpy.data.cameras.new("Camera"))
scene.collection.objects.link(cam); scene.camera = cam
cam.location = (6, -6, 4); cam.rotation_euler = (math.radians(60), 0, math.radians(45))
sun = bpy.data.objects.new("Sun", bpy.data.lights.new("Sun", "SUN"))
scene.collection.objects.link(sun)

The service sets engine (Cycles), resolution, samples and denoising; your script sets the scene, camera and frame range. Scripts run in an isolated container with no network. See samples/cube_scene.py.

HTTP API

POST /v1/keys                                   -> {api_key}         (header X-API-Key afterwards)
POST /v1/files  multipart "file" (.blend|.py)   -> {scene_id}
POST /v1/estimate {kind, frames|frame_start/frame_end, width, height, samples, scene_id?} -> seconds, wall_seconds, human, quota
POST /v1/jobs   {scene_id, kind: info|preview|final, frames|frame_start/frame_end, width, height, samples, camera, fps, output}
GET  /v1/jobs/{id}      status, progress, eta, artifacts[], cost, warnings, info    DELETE /v1/jobs/{id}  cancel
GET  /v1/jobs/{id}/artifacts/{name}             PNG / MP4
POST /mcp                                       remote MCP (Streamable HTTP; Bearer api key or OAuth)
GET  /.well-known/oauth-protected-resource/mcp  OAuth discovery
POST /v1/billing/checkout {amount_yen} -> {checkout_url}   POST /v1/billing/sync   GET /v1/ledger   GET /v1/me
GET  /llms.txt  /terms  /privacy  /legal  /security

During the free beta a 429 quota_exceeded response carries resets_at; a 400 beta_limit means the job is too big (split it). Once paid plans start, a 402 payment_required response carries checkout_url.

Self-hosting

The server (FastAPI + SQLite, with the remote MCP endpoint) and the worker (Blender in disposable Docker containers, --network none --cap-drop ALL) live in the internal repository and are not part of this package yet. This repository holds the client side: stdio MCP server, CLI, HTTP client, samples and the Claude Code plugin.

MCP registry

This server is listed in the official MCP registry as io.github.JasmyLab-JANCTION/janction-render (remote: https://render.janction.jp/mcp).

mcp-name: io.github.JasmyLab-JANCTION/janction-render

License

MIT (see LICENSE). Operated by JasmyLab Inc.