openclaw - 💡(How to fix) Fix ACP runtime sessions fail with 'acpx exited with code 1' — sessions_spawn runtime:"acp" broken in 2026.4.2 [1 comments, 2 participants]

Bug Description

sessions_spawn runtime:"acp" fails with "acpx exited with code 1" in OpenClaw 2026.4.2. This appears after the Task Flow system changes in the 2026.4.2 release.

Steps to Reproduce

1. Have Codex CLI installed and authenticated (codex auth status shows OK)
2. Attempt sessions_spawn runtime:"acp" with any task
3. ACP backend fails immediately with "acpx exited with code 1"

Expected Behavior

sessions_spawn runtime:"acp" should create a live ACP session and execute the task.

Actual Behavior

Background task failed: ACP background task (run XXX). acpx exited with code 1

The error occurs during session creation/repair, not during task execution.

Environment

• OpenClaw: 2026.4.2 (d74a122)
• macOS: Darwin 25.3.0 (arm64)
• Node: v22.22.0
• acpx: 0.4.0 (plugin-local, correctly installed at /opt/homebrew/lib/node_modules/openclaw/dist/extensions/acpx/node_modules/.bin/acpx)
• Codex CLI: v0.112.0, authenticated via ChatGPT Plus

Logs

[plugins] acpx ensureSession repairing dead named session: session=agent:claude:acp:... cwd=/Users/andreas/.openclaw/workspace status=dead summary=queue owner unavailable
[plugins] acpx ensureSession dead-session resume repair failed; retrying with fresh session owner: session=agent:claude:acp:... cwd=... resumeSessionId=... error=-32002: Resource not found: ...
[plugins] acpx ensureSession dead-session resume repair failed; retrying with fresh session owner: session=agent:claude:acp:... cwd=... resumeSessionId=... error=-32002: Resource not found: ...
[ws] res ✗ agent errorCode=UNAVAILABLE errorMessage=AcpRuntimeError: acpx exited with code 1

Direct acpx verification

The acpx binary works correctly when called directly:

• acpx codex sessions list → works
• acpx codex sessions new → creates session successfully
• acpx codex -s <session> <prompt> → executes prompts correctly

The issue is specifically in OpenClaw's ACP runtime integration, not in acpx itself.

Config

"plugins": {
  "entries": {
    "acpx": {
      "enabled": true,
      "config": {
        "permissionMode": "approve-all",
        "nonInteractivePermissions": "fail"
      }
    }
  }
}

Possible Related Changes (2026.4.2)

From CHANGELOG:

• "Tasks/Task Flow: restore the core Task Flow substrate with managed-vs-mirrored sync modes, durable flow state/revision tracking, and openclaw flows inspection/recovery primitives so background orchestration can persist..."
• "Plugins/Task Flow: add a bound api.runtime.taskFlow seam so plugins and trusted authoring layers can create and drive managed Task Flows from host-resolved OpenClaw context..."

This suggests significant changes to the Task Flow system that the ACP runtime depends on.

Impact

Cannot use sessions_spawn runtime:"acp" for background Codex tasks. Workaround is to use direct exec calls to acpx codex binary, but this bypasses OpenClaw's session management.