TUI hangs indefinitely on Working with tui_app_server enabled, while --disable tui_app_server works normally on 0.149.0

What version of Codex CLI is running?

0.149.0

What subscription do you have?

Pro

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Linux 5.4.0-81-generic x86_64 x86_64

What terminal emulator and version are you using (if applicable)?

VS Code Integrated Terminal 1.131.0 via Remote SSH on Linu

Codex doctor report

{
  "schemaVersion": 1,
  "generatedAt": "1787331198s since unix epoch",
  "overallStatus": "warning",
  "codexVersion": "0.149.0",
  "checks": {
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      "id": "app_server.status",
      "category": "app-server",
      "status": "ok",
      "summary": "background server is running",
      "details": {
        "app-server version": "0.149.0",
        "control socket": "/data/yezelin/.codex/app-server-control/app-server-control.sock",
        "daemon state dir": "/data/yezelin/.codex/app-server-daemon",
        "mode": "ephemeral",
        "pid file": "/data/yezelin/.codex/app-server-daemon/app-server.pid (missing)",
        "settings": "/data/yezelin/.codex/app-server-daemon/settings.json (missing)",
        "status": "running",
        "update-loop pid file": "/data/yezelin/.codex/app-server-daemon/app-server-updater.pid (missing)"
      },
      "remediation": null,
      "durationMs": 266
    },
    "auth.credentials": {
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      "category": "auth",
      "status": "ok",
      "summary": "auth is configured",
      "details": {
        "auth file": "/data/yezelin/.codex/auth.json",
        "auth storage mode": "File",
        "stored API key": "false",
        "stored ChatGPT tokens": "true",
        "stored agent identity": "false",
        "stored auth mode": "chatgpt"
      },
      "remediation": null,
      "durationMs": 0
    },
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      "status": "ok",
      "summary": "config loaded",
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        "config.toml parse": "ok",
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        "enabled feature flags": "shell_tool, view_image, unified_exec, shell_snapshot, code_mode_host, terminal_resize_reflow, sqlite, memories, hooks, enable_request_compression, unbounded_connection_retries, multi_agent, tool_search_always_defer_mcp_tools, tool_suggest, plugins, in_app_browser, in_app_chat, in_app_dictation, in_app_updates, browser_use, browser_use_full_cdp_access, browser_use_external, computer_use, remote_plugin, plugin_sharing, image_generation, resize_all_images, item_ids, skill_mcp_dependency_install, skill_search, mentions_v2, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, auth_elicitation, personality, fast_mode, tui_app_server, remote_compaction_v2, workspace_dependencies",
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        "git exec path": "/usr/lib/git-core",
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    "installation": {
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      "status": "ok",
      "summary": "installation looks consistent",
      "details": {
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        "PATH codex #2": "/data/yezelin/.local/bin/codex",
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    "mcp.config": {
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      "remediation": null,
      "durationMs": 0
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    "network.env": {
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      "status": "ok",
      "summary": "network-related environment looks readable",
      "details": {
        "managed proxy": "not configured",
        "proxy env vars present": "http_proxy, https_proxy",
        "respect system proxy": "disabled"
      },
      "remediation": null,
      "durationMs": 0
    },
    "network.provider_reachability": {
      "id": "network.provider_reachability",
      "category": "reachability",
      "status": "ok",
      "summary": "active provider endpoints are reachable over HTTP",
      "details": {
        "ChatGPT inference URL": "https://chatgpt.com/backend-api/<redacted> reachable (HTTP 405)",
        "reachability mode": "ChatGPT auth"
      },
      "remediation": null,
      "durationMs": 785
    },
    "network.websocket_reachability": {
      "id": "network.websocket_reachability",
      "category": "websocket",
      "status": "ok",
      "summary": "Responses WebSocket is not enabled for the active provider",
      "details": {
        "model provider": "openai-resilient",
        "provider name": "OpenAI",
        "proxy env vars present": "http_proxy, https_proxy",
        "supports websockets": "false",
        "wire API": "responses"
      },
      "remediation": null,
      "durationMs": 0
    },
    "runtime.provenance": {
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      "status": "ok",
      "summary": "running npm on linux-x86_64",
      "details": {
        "commit": "unknown",
        "current executable": "/data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin/codex",
        "install method": "npm (package /data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl, bin /data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin, resources /data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-resources, path /data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-path)",
        "platform": "linux-x86_64",
        "version": "0.149.0"
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    "runtime.search": {
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      "category": "search",
      "status": "ok",
      "summary": "search is OK (bundled)",
      "details": {
        "search command": "/data/yezelin/.local/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-path/rg",
        "search command readiness": "file exists",
        "search provider": "bundled"
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    "sandbox.helpers": {
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      "status": "ok",
      "summary": "sandbox configuration is readable",
      "details": {
        "approval policy": "OnRequest",
        "codex-linux-sandbox helper": "/data/yezelin/.codex/tmp/arg0/codex-arg0URQtld/codex-linux-sandbox",
        "execve wrapper helper": "/data/yezelin/.codex/tmp/arg0/codex-arg0URQtld/codex-execve-wrapper",
        "filesystem sandbox": "restricted",
        "network sandbox": "enabled"
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    "security.endpoint": {
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      "summary": "endpoint protection is not inspected on this platform",
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    "state.paths": {
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      "summary": "state paths and databases are inspectable",
      "details": {
        "CODEX_HOME": "/data/yezelin/.codex (dir)",
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        "archived rollout files": "3 files, 805003 total bytes, 268334 average bytes",
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        "goals DB integrity": "ok",
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        "log dir": "/data/yezelin/.codex/log (dir)",
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    "state.rollout_db_parity": {
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      "details": {
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        "rollout DB missing active sample": [
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          "/data/yezelin/.codex/sessions/2026/03/22/rollout-2026-03-22T18-27-00-019d16cc-e8ac-7a62-b72e-3034b6bf78dd.jsonl",
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}

What issue are you seeing?

On Codex CLI 0.149.0, the normal interactive TUI frequently hangs indefinitely at Working, even in a completely fresh session with a trivial prompt.

For example, starting:

codex

and sending:

Reply only OK

can leave the TUI at Working for many minutes. I have also observed a turn remain at Working for more than two hours without producing any output.

However, the same CLI and environment work normally when tui_app_server is disabled:

codex --disable tui_app_server -m gpt-5.6-sol

With this command, the same trivial prompt returns OK within a few seconds.

codex exec also completes successfully, although it sometimes emits model-manager timeout errors before the actual turn starts:

ERROR codex_models_manager::manager: failed to refresh available models: timeout waiting for child process to exit

For example:

time codex exec --skip-git-repo-check "Reply only OK"

completed successfully in approximately 33 seconds.

This strongly appears to be specific to the default TUI/app-server execution path rather than model inference itself.

What steps can reproduce the bug?

1.Install/run Codex CLI 0.149.0 on Linux x86_64.
2.Confirm the version:
codex --version
Output:
codex-cli 0.149.0
3.Start a completely fresh interactive session:
codex
4.Send a trivial prompt:
Reply only OK
5.Observe that the TUI remains at:
Working...
for minutes or indefinitely without producing a response.
6.Exit and repeat the same test with the app-server-backed TUI disabled:
codex --disable tui_app_server -m gpt-5.6-sol
7.Send the same trivial prompt.
Result: OK is returned within a few seconds.

I also tested with a fresh CODEX_HOME under /tmp to exclude existing sessions/state as the cause. The normal TUI still hangs:
CODEX_HOME=/tmp/codex-test-$USER codex
The underlying filesystem of the normal home directory is local ext4, not NFS/Ceph/Lustre.
While the normal TUI is hung, the native app-server and proxy processes remain alive with stable PIDs. Both binaries report:
codex-cli 0.149.0
All observed threads are in Sl state. The native app-server and proxy processes show approximately 0% CPU and are sleeping in:
futex_wait_queue_me
There is no observed crash/restart loop and no observed thread in D state.

What is the expected behavior?

A fresh interactive TUI session should process a trivial prompt normally and return a response within approximately the same time as the direct/non-app-server path.
In particular, the default:
codex
should not remain indefinitely at Working when:
codex --disable tui_app_server
can process the same prompt successfully within seconds.
If the app-server encounters an internal timeout or loses synchronization with the TUI, it should also surface an error or recover rather than leaving the turn permanently in the Working state.

Additional information

Workaround

The following consistently avoids the hang:

codex --disable tui_app_server -m gpt-5.6-sol
App-server versions

During earlier debugging, I discovered an old system-wide Codex 0.141.0 installation whose app-server processes were still running while my interactive CLI was newer.

Those stale processes were terminated.

I then reproduced the issue again after verifying that all relevant components were 0.149.0:

CLI: codex-cli 0.149.0
app-server: codex-cli 0.149.0
proxy: codex-cli 0.149.0

Therefore, the current reproduction is not caused by the earlier 0.141/0.149 version mismatch.

Process state while hung

The app-server and proxy PIDs remain stable rather than continuously restarting.

Example process state:

STAT %CPU WCHAN
Sl 0.0 futex_wait_queue_me
Sl 0.0 futex_wait_queue_me

All inspected threads were in Sl state.

Model manager observations

codex exec has emitted:

ERROR codex_models_manager::manager: failed to refresh available models: timeout waiting for child process to exit

twice during startup, but subsequently completed the request.

Model catalog timing:

$ time codex debug models >/tmp/codex-models-online.json
real 0m5.241s

$ time codex debug models --bundled >/tmp/codex-models-bundled.json
real 0m0.053s

I am not sure whether the model-manager timeout is directly responsible for the TUI/app-server hang, but it may be relevant.

Other controls
Fresh session reproduces the issue.
Fresh CODEX_HOME under /tmp also reproduces it.
Home filesystem is local ext4.
Codex state database was reported healthy by codex doctor.
Provider endpoints are reachable over HTTP.
codex exec can successfully invoke the model.
--disable tui_app_server consistently avoids the hang.
App-server and proxy are both confirmed to be 0.149.0.

Reproduce the indefinite TUI hang on Linux with Codex CLI 0.149.0 and tui_app_server enabled, then compare it with the working --disable tui_app_server case. Trace the TUI/app-server startup path and use the supplied doctor report and configuration details to identify where progress stops. Done means the TUI no longer hangs when tui_app_server is enabled.