DeepAgents onboard hangs waiting for startup output on macOS VM driver #5766

Agent Diagnostic

• Loaded nemoclaw-contributor-create-pr for branch/PR workflow.
• Investigated a live langchain-deepagents-code onboard run on macOS/OpenShell VM driver.
• openshell sandbox list showed sandbox dp in Ready phase while NemoClaw kept printing Sandbox reported Ready; waiting for startup command output before detaching.
• openshell sandbox get dp showed DeepAgents/terminal policy state (/sandbox/.deepagents, dcode).
• In-sandbox checks confirmed /sandbox/.deepagents/config.toml exists and dcode --version works.
• /var/log/openshell.2026-06-25.log showed normal startup and OCSF PROC:LAUNCH [INFO] sleep(26), with no sandbox crash.

Description

On macOS/OpenShell VM driver, nemoclaw onboard --agent langchain-deepagents-code can hang after the sandbox reaches Ready. NemoClaw waits for startup command output before detaching from the create stream, but terminal-runtime DeepAgents does not provide a long-running gateway/dashboard startup stream.

Expected behavior: once OpenShell reports the terminal-agent sandbox as Ready, NemoClaw should continue onboarding and register the sandbox.

Actual behavior: onboarding repeatedly prints Still waiting for sandbox to become ready... even though OpenShell reports the sandbox is already Ready. Ubuntu/Docker-driver onboarding does not reproduce because that path does not require the VM startup-output guard.

Reproduction Steps

1. On macOS with OpenShell VM driver, run nemoclaw onboard --agent langchain-deepagents-code.
2. Use a hosted NVIDIA provider/model.
3. Wait for image build and sandbox create.
4. Observe Sandbox reported Ready; waiting for startup command output before detaching. followed by repeated ready-wait messages.
5. In another shell, run openshell sandbox list and observe the sandbox is Ready.

Environment

• OS: macOS host using OpenShell VM driver
• Agent: langchain-deepagents-code
• Provider: NVIDIA hosted endpoint
• Ubuntu/Docker-driver comparison: works without this hang
• NemoClaw commit observed around ae94f134c

Debug Output

$ openshell sandbox list
NAME  CREATED              PHASE
dp    2026-06-25 04:31:18  Ready

$ openshell sandbox exec -n dp -- sh -lc "test -s /sandbox/.deepagents/config.toml && dcode --version"
deepagents-code 0.1.12
deepagents (SDK) 0.6.8

Logs

Sandbox reported Ready; waiting for startup command output before detaching.
Still waiting for sandbox to become ready... (40s elapsed)
Still waiting for sandbox to become ready... (45s elapsed)
...

/var/log/openshell.2026-06-25.log:
2026-06-25T04:23:21.919Z OCSF PROC:LAUNCH [INFO] sleep(26)

Checklist

• I confirmed this bug is reproducible
• I searched existing issues and this is not a duplicate