sandbox start fails after initial command exits: 'supervisor authentication bundle does not match runtime session' #4505

Summary

Starting a sandbox whose initial command already finished (phase Completed) fails deterministically and moves the sandbox to Error. Creating a sandbox and running a command via sandbox create works fine; only restarting a stopped/completed sandbox is affected.

Environment

• OpenShell 0.1.3 (CLI, gateway, sandbox, driver-vm)
• Install method: Arch-based distro (CachyOS). The official install.sh supports only snap/deb/rpm, so I used the AUR package openshell-bin 0.1.3-1, which repackages the official release tarballs (sha256 verified against the release checksums file).
• Gateway: local, native systemd user service (systemctl --user), mTLS
• Registration: openshell gateway add https://127.0.0.1:17670 --local --name openshell → Connected / Authenticated (mTLS)
• Compute driver: Docker 29.9.0 (user is in the docker group); openshell doctor check passes
• Host: Linux x86_64, kernel 7.2.9, CachyOS
• Default sandbox image: nvcr.io/nvidia/base/ubuntu:24.04

Steps to reproduce

1. openshell sandbox create --name repro1 -- echo done → runs fine; sandbox reaches phase Completed
2. openshell sandbox start repro1

Actual

Error: code: 'The service is currently unavailable', message: "start sandbox failed: Docker supervisor exited before becoming ready; log tail: 2026-10-13T21:45:18.451Z INFO openshell_supervisor: Starting sandbox supervision
Error: supervisor authentication bundle does not match runtime session"

The sandbox transitions to phase Error. A subsequent openshell sandbox exec repro1 -- ... reports not ready (phase: Error). Reproduced with two independent sandboxes. The gateway was NOT restarted between creation and start.

Relevant sandbox-side log lines from the failed start (openshell logs repro1):

[sandbox] CONFIG:ENABLED TLS termination enabled: ephemeral CA generated
[sandbox] WARN host.openshell.internal maps to a non-link-local IP; trusted-gateway SSRF exemption disabled ip=127.0.0.1
[sandbox] NET:OPEN 127.0.0.1:17670
[gateway] supervisor session: superseded by reconnect, shutting down
[gateway] supervisor session: ended (already superseded)
[gateway] Stopped Docker sandbox after control supervisor failure
[gateway] Container exited

openshell sandbox get repro1 after the failure:

Phase: Error
Configuration: ConfigurationPending: Waiting for effective configuration validation before workload activation
Main process instance: e9924d02-442b-4c85-943b-efd169c12405
Annotations:
  internal.openshell.ai/auth-epoch: 2
  internal.openshell.ai/runtime-generation: 4ae09559-7423-4685-9bf4-0ae105d8ee5b
Conditions:
  - Ready: False (ContainerExited) - Container exited
  - ConfigurationReady: False (ConfigurationPending)

Expected

sandbox create → Completed → sandbox start → Ready.

Workaround

Delete the sandbox and create a new one (works immediately, image is cached).