Cloud desktops for computer-use agents
Lightcone OS is a Linux desktop runtime built for models to operate. Northstar, our computer-use model, comes built in.
A sandbox built for models, and models built for autonomy.
Lightcone OS
A minimal Linux desktop with deterministic rendering on every instance — models act more reliably when every screen looks the same. Chromium with stealth mode, a full shell, and snapshots.
Northstar
Our computer-use model: screenshot in, structured action out, at 560 ms median per action with 92%+ grounding on ScreenSpot‑v2. It recovers from mistakes and generalizes across desktop and browser environments.
Own as much of the loop as you want.
Tasks
Describe an outcome; Northstar runs the whole loop and streams progress.
for event in client.agent.tasks.start_stream(
instruction="Export last month's invoices and file them by vendor.",
kind="desktop",
):
print(event)Responses
The model picks each action; you execute it and feed back a screenshot.
res = client.responses.create(
model="tzafon.northstar-cua-fast-1.6",
input="Open the reports dashboard",
tools=[{"type": "computer_use", "environment": "browser"}],
)
execute(res.output) # your loop, your rulesComputers
Cloud browsers and desktops for your own model or automation.
computer = client.computers.create(kind="desktop")
client.computers.click(computer.id, x=512, y=310)
client.computers.type(computer.id, text="Q3 report")
shot = client.computers.screenshot(computer.id)Runs what you already built.
E2B SDK workloads run with a config change. Playwright connects over CDP. Tools ship for LangChain, Vercel AI SDK, Mastra, Browser-Use, and MCP — and the API speaks the OpenAI and Anthropic dialects.
0ms
Lightcone browser
0ms
Lightcone desktop
0ms
Leading sandbox provider
Server-side create time (TTFB minus TLS handshake), median of five runs, measured 2026-07-22 from one client at ~19ms RTT to both providers.
$0.50
Per million input tokens
$1.50
Per million output tokens
$0.075
Per browser-hour, billed per second
$0
Setup fees and monthly minimums
Start with a key and five lines.
$ pip install tzafon
from tzafon import Lightcone
client = Lightcone()
for event in client.agent.tasks.start_stream(
instruction="Find the cheapest nonstop SFO->Tokyo over the next three weeks.",
kind="browser",
):
print(event)