A self_hosted Session runs on a machine your application owns: a workstation, a VM or a sandbox you manage. The application creates the Session through /v1 and receives a command that installs oac-daemon, starts it and connects it to Core. Web shows the same command on the Session's page; it is optional. Core never creates, stops or reclaims the machine.

The daemon is not a sandbox. Tools run with the permissions of the account that starts it and can reach whatever that account can. Use a container or VM when you need isolation; see Runtime and outer isolation. The daemon does not restrict network access, so a Template that requires a network policy is rejected for a self-hosted Session.

The Session brings its own model provider; the installation default never applies (why). The machine gets an executor credential that works for this one Environment and nothing else.

Platforms

Platform	Codex	Claude Code	MiniMax Code
Linux amd64	Supported	Supported	Supported
macOS arm64	Supported	Supported	Supported
Windows amd64	Supported	Supported	Not supported

The installer brings its own pinned Node.js and Harness versions (listed in scripts/build-native-installer.mjs) and leaves other installations of those tools untouched. On a platform without a matching installer, the command fails.

The machine needs:

• HTTPS access to Core (plain HTTP only on loopback), and to the release download host unless Core carries an offline copy of the installers;
• Bash for environment setup and MiniMax Code tools; on Windows, Git Bash, which Claude Code also requires;
• Python and pip when the Session's packages need them;
• any system packages your setup needs. The daemon never runs apt, sudo or another elevation command, so install them through the host's normal administration.

No administrator privileges or Docker are needed. The Unix download command also uses curl, tar, gzip, a SHA-256 tool and the system file-lock command (flock on Linux, lockf on macOS).

Connect a machine

1. Choose an absolute workspace path on the target machine. Create a Session with that path and the application's Project API key:

   import os
   from openai import OpenAI
   
   client = OpenAI()  # reads OPENAI_BASE_URL and OPENAI_API_KEY
   session = client.beta.agents.sessions.create(
       environment={
           "type": "self_hosted",
           "workspace_directory": os.environ["EXECUTOR_WORKSPACE"],
       },
       extra_body={
           "agent": {"model": os.environ["MODEL_NAME"], "x_agents_core": {"harness": "codex"}},
           "x_agents_core": {"model_provider": {
               "protocol": "responses",
               "base_url": os.environ["MODEL_BASE_URL"],
               "api_key": os.environ["MODEL_API_KEY"],
           }},
       },
   )
   installation = session.model_dump()["x_agents_core"]["installation"]
   print(installation["commands"]["posix"])  # use "powershell" on Windows

2. Run the command on the target machine with the account that should run the tools. It downloads the installer matched to this Core, verifies its checksum, asks which Harnesses to install and where, installs them, creates the workspace if needed, starts the daemon and checks its connection.

3. Send a Turn. A connected machine proves only authentication; the first Turn checks the Harness and the model.

In Web, open the Session and copy the command under Connect a host.

Keep the command private: it carries a short-lived installation grant that claims the machine's credential. When it has expired, read the Session again or copy a fresh command from Web.

The installer reports three results:

Result	Meaning
Installation	The selected Harnesses passed their readiness checks
Daemon connection	Core confirmed the daemon's authenticated connection
Model configuration	Not checked; the first Turn uses the Session's model provider

Downloads retry temporary network failures up to three attempts and show progress in a terminal. Disk space is checked before downloading, extracting and copying components. If a download or installation is interrupted, rerun the command: it clears unfinished temporary copies while preserving completed components, credentials and the workspace. Download staging lives in native-download under the Runtime home; its small download.lock file remains for concurrency control. An active download or installation is never cleared by another run. If the command expires, copy a fresh one from the Session.

If the connection is not confirmed within 45 seconds, the installer prints the path of the daemon's log. The daemon keeps reconnecting. Fix the cause and run the install command again with the same installation directory, copying a fresh one from Web if it has expired: completed components and the credential are kept and a running daemon is reused. Do not remove the workspace or the Session to retry.

Options for automation

Append these to the command:

Option	Effect
--non-interactive	Never prompt; missing input fails
--harness codex,claude,minimax	Harnesses to install, comma-separated. Must include the Session's Harness
--install-dir ABS	Installation directory. Default: environments/<environment-id> under ~/.oac, or under OAC_RUNTIME_HOME when set
--capability-directory ABS	Where capability snapshots are stored. Default: capabilities in the installation directory
--tool-env-file ABS	A JSON file of string variables for tools and MCP servers; see explicit local tool environment

The workspace is fixed when the Session is created. For a different workspace, create another Session.

Local capability directories

A self-hosted Session may supply capability_directories alongside its workspace:

environment = {
    "type": "self_hosted",
    "workspace_directory": os.environ["EXECUTOR_WORKSPACE"],
    "capability_directories": [os.environ["EXECUTOR_CAPABILITIES"]],
}

Paths are absolute in the machine's own syntax (Unix, Windows drive or UNC); the daemon checks them, not Core. Fill these directories before the daemon connects. They are ordinary paths visible to the daemon; naming one does not mount it or create a sandbox.

Use x_agents_core.environment for the same Project-owned Skills, Plugin archives, files, packages, setup commands or Template used by a managed Session:

session = client.beta.agents.sessions.create(
    agent_id=agent_id,
    environment=environment,
    extra_body={"x_agents_core": {
        "model_provider": model_provider,
        "environment": {"environment_template_id": template_id},
    }},
)

The same extension works with environment={"type": "openai_hosted"}. Do not repeat a field in both environment and the extension. Setup runs with the daemon's account permissions. Deployment model keys are never sent to your machine.

Before the first Turn the daemon copies these sources into a snapshot. Reconnecting reuses the snapshot even after you edit the sources; a new Session takes a new snapshot. The preparation contract lists fields, merge rules, snapshot behavior and failures.

Operate the installation

The installation's bin/oac-daemon finds its own installation. Use it for:

Command	Effect
oac-daemon start	Validate the installed Harnesses and start the daemon in the background
oac-daemon status	Show the local profile and process; not the connection
oac-daemon logs -n 100, oac-daemon logs -f	Print or follow the daemon log
oac-daemon stop	Stop the daemon

If you set OAC_RUNTIME_HOME, use the same value for every command. Check the connection under Host connection on the Session's page in Web, or with the connection status.

To add a Harness, run the install command again (a fresh copy from Web if it has expired) with the same installation directory and the Harness to add. The installer checks the existing contents, adds only missing components and keeps the Harnesses already installed. Restart a running daemon afterwards so it discovers the new Harness.

Stopping the daemon, cancelling a Turn or deleting the Session never removes the machine's workspace, native history or capability snapshot. An installation from another daemon version, or one whose files were changed, is refused. The installer never upgrades, repairs or migrates it; install into a separate directory.

Rotate or revoke

In Web, the Session's Executor credentials list the machine's credential:

Action	Effect
Rotate	The credential gets a new secret; the old secret stops working at once. On a revoked credential the action is Restore
Revoke	The credential stops working at once

To reconnect after a rotation, stop the daemon with oac-daemon stop, replace the JSON at its configured credential-file path with the new credential, and run oac-daemon start. Do not run install again over the existing installation, and rotate the existing credential rather than issuing a second one, which cannot connect.

In an archived Project, credentials cannot be issued or rotated; revocation remains available. Operators can manage credentials with the Core key; see the credential contract.

Install from an extracted distribution

The same installer accepts an already extracted distribution and a credential file issued by an operator, without the install command:

./oac-daemon install --non-interactive --harness codex \
  --install-dir "$HOME/.oac/my-runtime" \
  --remote 'wss://core.example/api/v1/agent-daemon/ws' \
  --environment-id '11111111-2222-4333-8444-555555555555' \
  --workspace "$HOME/workspace" \
  --credential-file "$HOME/executor-credential.json"
"$HOME/.oac/my-runtime/bin/oac-daemon" start

Use the Session's remote_url and Environment ID. In PowerShell, run .\oac-daemon.exe with native absolute paths. This mode needs an existing workspace and does not start the daemon until you run start.