cua (Python)

The cua SDK for Python: a thin, generated binding over the Rust cua-sdk crate (libs/cua/crates/cua-sdk). The same API runs embedded in your process or against a cua daemon that shares sandboxes, spacesd connections and credentials across processes.

import asyncio, cua

async def main():
    c = cua.embedded()
    sb = await c.sandboxes().connect_url("http://127.0.0.1:3211", "token", "dev")
    env = await sb.spacesd(None)
    print((await env.run(cua.SpacesdCommand(program="uname", args=["-a"]))).stdout.decode())
    png = await env.screenshot(None)

asyncio.run(main())

Sandboxes: any image, local or cloud

c = cua.embedded()
sb = await c.sandboxes().create(cua.SandboxCreateOptions(
    on="local",                                   # or "cloud": same options
    image="python:3.12-slim",
    command=["python", "-m", "my_mcp", "--port", "8765"],
    env={"FOO": "bar"},
    services={"mcp": 8765},
    wait_for=[cua.ReadinessProbe(port=0, service="mcp", http_path="/health")],
    cloud=cua.CloudOptions(warm=True),            # optional, ignored locally
))
svc = sb.service("mcp")
r = await svc.request("POST", "/mcp", body, None, [cua.HttpHeader(name="accept", value="application/json, text/event-stream")])
url = await svc.url()                             # usable from this machine
share = await sb.public_url("mcp", 3600, None)    # shareable, expires
fwd = await sb.forward(8765)                      # loopback URL: fwd.url()
info = sb.info()  # id, phase, location, services, expires_at_unix, provider_details

public_url is a signed URL in the cloud and a loopback URL with its own token locally, served by the cua daemon (started on demand with the bundled CLI). await sb.mcp("mcp", None) is an MCP client for a server the sandbox serves and await sb.mcp_config("mcp", None) its URL and headers for any MCP client; neither needs cua-spacesd. cua.canonical_image("linux", None) returns ghcr.io/trycua/linux:24.04. Cloud env, sidecars (addressed by name, on gVisor and KubeVirt) and registry secrets work like local ones; cloud image layers (a remote build) are not available yet and fail with a clear error.

High-level API (optional extras)

cua replaces the former cua meta-package (0.1.x). Its convenience imports resolve lazily from optional extras:

pip install "cua[sandbox]"   # cua-sandbox: Sandbox, Image, Pool, QEMURuntime, ...
pip install "cua[agent]"     # cua-agent: ComputerAgent, cua.callbacks, cua.tools
pip install "cua[all]"       # both (the `cua` command is the Rust CLI in libs/cua)

from cua import Sandbox, Image            # cua_sandbox.Sandbox / Image
async with Sandbox.ephemeral(Image.linux(), local=True) as sb:
    print((await sb.shell.run("uname -a")).stdout)

With cua-sandbox installed, cua.Sandbox is the high-level cua_sandbox.Sandbox; the SDK's own handle type (what sandboxes().create() returns) is always cua.SandboxHandle.

• cua._native is generated by libs/cua/scripts/generate-uniffi-bindings.mjs and must not be edited; --check fails CI when it drifts.
• Wheels are platform wheels (build_wheel.py), one per OS/arch, each with the libcua_sdk library next to _native.py.

Development

cd libs/cua
cargo build --release -p cua-sdk
scripts/build-test-fixtures.sh
node scripts/stage-uniffi-library.mjs          # copies the library here
cd python && uv run --with pytest pytest -q    # smoke tests against fixtures
CUA_E2E_FLEET=1 uv run --with pytest pytest -q tests/test_live_fleet.py  # live Fleet