Store and persist artifacts

Read, write, download, and persist files under the artifact root.

The default artifact root is /home/desktop/artifacts. Public artifact methods accept safe relative paths under that root.

Write and read an artifact

info = computer.artifacts.write_bytes(
    "runs/example/result.txt",
    b"hello\n",
    "text/plain",
)
data = computer.artifacts.read_bytes("runs/example/result.txt")
print(info.size_bytes, len(data))

Use a separate prefix for each run. This prevents unrelated runs from writing the same file.

Upload and download files

from pathlib import Path

computer.artifacts.upload(
    Path("input.txt"),
    "runs/example/input.txt",
)
computer.artifacts.download(
    "runs/example/input.txt",
    Path("downloads/input.txt"),
)

List or delete public artifacts with the same relative paths:

items = computer.artifacts.list(prefix="runs/example")
computer.artifacts.delete("runs/example/input.txt")

logs/, manifest.ndjson, and traces/actions.ndjson are internal control paths. Read process logs through computer.processes.logs() or computer.processes.stderr().

Understand default storage

Artifact files use the Sandbox filesystem by default. They disappear when the Sandbox terminates.

Mount a Modal Volume v2 when files must remain after termination. Set persist_artifacts=True and call computer.artifacts.sync() before you terminate the Sandbox.

Persist to a Modal Volume v2

import modal
from modal_proto import api_pb2

from modal_computer_use import ComputerConfig, ComputerSandbox, StorageConfig

artifacts_dir = "/home/desktop/artifacts"
volume = modal.Volume.from_name(
    "computer-use-artifacts",
    create_if_missing=False,
    version=api_pb2.VolumeFsVersion.Value("VOLUME_FS_VERSION_V2"),
).hydrate()

computer = ComputerSandbox.create(
    config=ComputerConfig(
        run_id="replace-with-a-unique-run-id",
        storage=StorageConfig(persist_artifacts=True),
    ),
    volumes={artifacts_dir: volume},
    wait=False,
)
try:
    computer.wait_until_ready()
    computer.artifacts.write_bytes(
        "runs/example/result.txt",
        b"hello\n",
        "text/plain",
    )
    sync = computer.artifacts.sync()
    if not sync.ok or not sync.persistent:
        raise RuntimeError("artifact sync did not persist")
finally:
    try:
        computer.terminate(wait=True)
    finally:
        computer.detach()

The sync contract supports Modal Volume v2. Modal Volume v1 is not a supported immediate-sync target for this package.

An existing reader must reload its Volume view after the writer commits. Avoid concurrent writes to one path because Volume conflict resolution uses the last writer.

Artifact paths and URIs can reveal run details. Do not log them unless your logging policy permits that data.