/fast mode disappeared in Ubuntu CLI
Open 💬 4 comments Opened May 19, 2026 by muddlebee
💡 Likely answer: A maintainer (github-actions[bot], contributor)
responded on this thread — see the highlighted reply below.
What version of Codex CLI is running?
codex-cli 0.131.0
What subscription do you have?
Codex Pro
Which model were you using?
all
What platform is your computer?
Ubuntu
What terminal emulator and version are you using (if applicable)?
Bash
Codex doctor report
{
"schemaVersion": 1,
"generatedAt": "1779217857s since unix epoch",
"overallStatus": "warning",
"codexVersion": "0.131.0",
"checks": {
"app_server.status": {
"id": "app_server.status",
"category": "app-server",
"status": "ok",
"summary": "background server is not running",
"details": {
"control socket": "/home/muddles/.codex/app-server-control/app-server-control.sock",
"daemon state dir": "/home/muddles/.codex/app-server-daemon",
"mode": "ephemeral",
"pid file": "/home/muddles/.codex/app-server-daemon/app-server.pid (missing)",
"settings": "/home/muddles/.codex/app-server-daemon/settings.json (missing)",
"status": "not running",
"update-loop pid file": "/home/muddles/.codex/app-server-daemon/app-server-updater.pid (missing)"
},
"remediation": null,
"durationMs": 0
},
"auth.credentials": {
"id": "auth.credentials",
"category": "auth",
"status": "ok",
"summary": "auth is configured",
"details": {
"auth file": "/home/muddles/.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
},
"config.load": {
"id": "config.load",
"category": "config",
"status": "ok",
"summary": "config loaded",
"details": {
"CODEX_HOME": "/home/muddles/.codex",
"config.toml": "/home/muddles/.codex/config.toml",
"config.toml parse": "ok",
"cwd": "/home/muddles/Codes/opensre",
"enabled feature flags": "shell_tool, unified_exec, shell_snapshot, terminal_resize_reflow, sqlite, hooks, enable_request_compression, multi_agent, apps, tool_search, tool_suggest, plugins, plugin_hooks, in_app_browser, browser_use, browser_use_external, computer_use, plugin_sharing, image_generation, skill_mcp_dependency_install, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, personality, fast_mode, tui_app_server, workspace_dependencies",
"feature flag overrides": "goals=true",
"feature flags enabled": "29",
"log dir": "/home/muddles/.codex/log",
"mcp servers": "4",
"model": "gpt-5.3-codex",
"model provider": "openai",
"sqlite home": "/home/muddles/.codex"
},
"remediation": null,
"durationMs": 0
},
"installation": {
"id": "installation",
"category": "install",
"status": "ok",
"summary": "installation looks consistent",
"details": {
"PATH codex #1": "/home/muddles/.nvm/versions/node/v24.15.0/bin/codex",
"current executable": "/home/muddles/.nvm/versions/node/v24.15.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex/codex",
"install context": "npm",
"managed by bun": "false",
"managed by npm": "true",
"managed package root": "/home/muddles/.nvm/versions/node/v24.15.0/lib/node_modules/@openai/codex",
"npm update target": "/home/muddles/.nvm/versions/node/v24.15.0/lib/node_modules/@openai/codex"
},
"remediation": null,
"durationMs": 82
},
"mcp.config": {
"id": "mcp.config",
"category": "mcp",
"status": "ok",
"summary": "MCP configuration is locally consistent",
"details": {
"configured servers": "4",
"disabled servers": "0",
"stdio servers": "3",
"streamable_http servers": "1"
},
"remediation": null,
"durationMs": 1087
},
"network.env": {
"id": "network.env",
"category": "network",
"status": "ok",
"summary": "network-related environment looks readable",
"details": {
"proxy env vars": "none"
},
"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 base URL": "https://chatgpt.com/backend-api/ reachable (HTTP 403)",
"reachability mode": "ChatGPT auth"
},
"remediation": null,
"durationMs": 163
},
"network.websocket_reachability": {
"id": "network.websocket_reachability",
"category": "websocket",
"status": "ok",
"summary": "Responses WebSocket handshake succeeded",
"details": {
"DNS": "2 IPv4, 1 IPv6, first IPv6",
"auth mode": "chatgpt",
"connect timeout": "15000 ms",
"endpoint": "wss://chatgpt.com/backend-api/<redacted>",
"handshake result": "HTTP 101 Switching Protocols",
"model provider": "openai",
"models etag present": "true",
"provider name": "OpenAI",
"proxy env vars": "none",
"reasoning header": "false",
"server model present": "false",
"supports websockets": "true",
"wire API": "responses"
},
"remediation": null,
"durationMs": 1079
},
"runtime.provenance": {
"id": "runtime.provenance",
"category": "runtime",
"status": "ok",
"summary": "running npm on linux-x86_64",
"details": {
"commit": "unknown",
"current executable": "/home/muddles/.nvm/versions/node/v24.15.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex/codex",
"install method": "npm",
"platform": "linux-x86_64",
"version": "0.131.0"
},
"remediation": null,
"durationMs": 0
},
"runtime.search": {
"id": "runtime.search",
"category": "search",
"status": "ok",
"summary": "search is OK (system)",
"details": {
"search command": "rg",
"search command readiness": "ripgrep 15.1.0 (rev af60c2de9d)",
"search provider": "system"
},
"remediation": null,
"durationMs": 1
},
"sandbox.helpers": {
"id": "sandbox.helpers",
"category": "sandbox",
"status": "ok",
"summary": "sandbox configuration is readable",
"details": {
"approval policy": "OnRequest",
"codex-linux-sandbox helper": "/home/muddles/.codex/tmp/arg0/codex-arg02hgN9d/codex-linux-sandbox",
"execve wrapper helper": "/home/muddles/.codex/tmp/arg0/codex-arg02hgN9d/codex-execve-wrapper",
"filesystem sandbox": "restricted",
"network sandbox": "restricted"
},
"remediation": null,
"durationMs": 0
},
"state.paths": {
"id": "state.paths",
"category": "state",
"status": "ok",
"summary": "state paths and databases are inspectable",
"details": {
"CODEX_HOME": "/home/muddles/.codex (dir)",
"active rollout files": "315 files, 153999207 total bytes, 488886 average bytes",
"archived rollout files": "0 files, 0 total bytes, 0 average bytes",
"log DB": "/home/muddles/.codex/logs_2.sqlite (file)",
"log DB integrity": "ok",
"log dir": "/home/muddles/.codex/log (dir)",
"sqlite home": "/home/muddles/.codex (dir)",
"state DB": "/home/muddles/.codex/state_5.sqlite (file)",
"state DB integrity": "ok"
},
"remediation": null,
"durationMs": 3339
},
"terminal.env": {
"id": "terminal.env",
"category": "terminal",
"status": "warning",
"summary": "locale is not UTF-8 - unicode glyphs may render incorrectly",
"details": {
"CLICOLOR": "256",
"COLORTERM": "truecolor",
"DISPLAY": "present",
"WAYLAND_DISPLAY": "present",
"color output": "enabled",
"effective locale": "en_IN",
"stderr is terminal": "true",
"stdin is terminal": "true",
"stdout is terminal": "true",
"terminal": "GNOME Terminal",
"terminal size": "80x26"
},
"issues": [
{
"severity": "warning",
"cause": "locale is not UTF-8 - unicode glyphs may render incorrectly",
"measured": "en_IN",
"expected": "UTF-8 locale, for example en_US.UTF-8",
"remedy": "export LANG=en_US.UTF-8 or another UTF-8 locale",
"fields": [
"effective locale"
]
}
],
"remediation": null,
"durationMs": 0
},
"updates.status": {
"id": "updates.status",
"category": "updates",
"status": "ok",
"summary": "update configuration is locally consistent",
"details": {
"cached latest version": "0.131.0",
"check for update on startup": "true",
"last checked at": "2026-05-19T05:10:41.614473661Z",
"latest version": "0.131.0",
"latest version status": "current version is not older",
"npm update target": "/home/muddles/.nvm/versions/node/v24.15.0/lib/node_modules/@openai/codex",
"update action": "npm install -g @openai/codex",
"version cache": "/home/muddles/.codex/version.json"
},
"remediation": null,
"durationMs": 571
}
}
}What issue are you seeing?
/fast mode is not coming anymore
What steps can reproduce the bug?
same
What is the expected behavior?
_No response_
Additional information
_No response_
4 Comments
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
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Fast mode is available only for certain models. The command is not available if the model doesn't support it.
@etraut-openai thank you, but it was working with codex earlier :/
also fast mode works with codex models if I set at config.toml, weird
I am seeing a very similar issue on macOS with the Codex App-bundled CLI.
Environment:
26.527.31326codex-cli 0.135.0-alpha.1/Applications/Codex.app/Contents/Resources/codexgpt-5.5codex features listshowsfast_mode stable truegpt-5.5hasadditional_speed_tiers=["fast"]Observed:
Fast off/fast statusin the CLI returns:I also tried starting the TUI with:
The footer still displayed
Fast offin my spot check.One extra detail:
codex updateattemptsbrew upgrade --cask codexon this machine, but Homebrew reports:So this looks less like an unsupported-model case and more like Fast mode support is present in the build, but the
/fastslash command is not registered in the CLI/TUI command table for this channel/build.