System and Third-Party

Claude Code reads many variables that it does not define. Your system, your terminal, CI services, and other tools own them. Examples are HOME, PATH, EDITOR, TERM, and ALL_PROXY. Claude Code reads them to find files, pick colors, and detect where it runs.

This page lists 130 variables. You set many of them for your system anyway. Set them in your shell, or in the env key of a settings file.

Example

export EDITOR="code --wait"
claude

Claude Code opens this editor for files, for example for /memory. VISUAL wins over EDITOR.

Variables

The table is sorted by name. See Environment Variables for what each column and badge means.

Variable	Status	What it does	Values and default	Notes
__CFBundleIdentifier	Undocumented	MacOS bundle id of the app that started the process. Claude Code uses it to find the host app and the URL handler.	Text. Non-empty string. com.anthropic.claude-code-url-handler starts the deep link path	MacOS
AGENT_NAME	Undocumented	Confirms an Azure Pipelines agent for the terminal color level.	Text. Presence test together with TF_BUILD	All sessions
ALACRITTY_LOG	Undocumented	Terminal detection. A set value counts as an Alacritty terminal in a terminal-feature check and rules out a plain VTE terminal.	On or off. Truthy test only. Read from the env object and from the env of the terminal detector	Terminal UI rendering, all. Not set from project env before trust
ALACRITTY_WINDOW_ID	Undocumented	Terminal detection. A set value rules out a plain vte-based or gnome-terminal guess, because Alacritty sets it.	On or off. Truthy test only, in the terminal detector	Terminal UI rendering, all. Not set from project env before trust
ALL_PROXY	Documented	Standard proxy variable. Claude Code passes it to git as http.proxy and remote.origin.proxy when it runs git commands.	Text. Read after HTTPS_PROXY and https_proxy, with the lowercase all_proxy as the last fallback	Git helper commands, all. Not set from project env before trust
ALLUSERSPROFILE	Undocumented	Windows path variable. It is the last fallback for the ProgramData folder when Claude Code builds the Windows Start Menu path.	Text. Order is ProgramData, then PROGRAMDATA, then ALLUSERSPROFILE. Also in a list of Windows path names	Windows. Not set from project env before trust
ANDROID_HOME	Undocumented	Environment detection. If the path exists, Claude Code records android-sdk in the detected build tools.	Text. Read first, with ANDROID_SDK_ROOT as the fallback. Only the path check matters	Environment report, all. Not set from project env before trust
ANDROID_SDK_ROOT	Undocumented	Environment detection. It is the fallback for ANDROID_HOME. If the path exists, Claude Code records android-sdk in the detected build tools.	Text. Read only when ANDROID_HOME is unset	Environment report, all. Not set from project env before trust
APPDATA	Documented	Windows path variable. Claude Code uses it for the gcloud config folder, the Alacritty config path, and a Windows path list.	Text. Used on Windows only for gcloud and Alacritty paths	Windows. Not set from project env before trust
APPVEYOR	Undocumented	Names AppVeyor for the terminal color level.	Presence test, only when CI is set. Gives color level 1	All sessions
AWS_EXECUTION_ENV	Undocumented	Names the AWS runtime. Claude Code uses it to detect aws-fargate and aws-ecs as the deployment environment. The AWS SDK adds it to its user agent.	Compared with AWS_ECS_FARGATE and AWS_ECS_EC2	All (deployment detection) and AWS SDK calls
AWS_LAMBDA_FUNCTION_NAME	Undocumented	Marks an AWS Lambda host. Claude Code reports aws-lambda as the deployment environment when it is set.	Text. Any non-empty value. The AWS SDK also reads it for trace headers	All (deployment detection)
AWS_PAGER	Undocumented	Sets the pager of the AWS CLI. Claude Code lists it among env names that can run a program, for safety checks.	Text. No direct read	Settings env and Bash safety checks
AZURE_AUTH_LOCATION	Undocumented	Names an Azure auth file path. Claude Code lists it among credential file names to protect.	Text. No direct read	Settings env and sandbox credential lists
AZURE_CONFIG_DIR	Undocumented	Sets the Azure CLI config folder. Claude Code treats it as a credential path to protect, default ~/.azure.	Text	Sandbox credential deny paths
AZURE_FUNCTIONS_ENVIRONMENT	Undocumented	Marks an Azure Functions host. Claude Code reports azure-functions as the deployment environment when it is set.	Any non-empty value	All (deployment detection)
BASH_ENV	Documented	Names the startup file that bash reads. Claude Code treats it as an unsafe inlet and flags it in settings and plugin env.	Claude Code never reads it for its own use	Settings env, plugin env, sandbox checks
BROWSER	Documented	Names the command that opens URLs. Claude Code uses it before open on macOS, and the browser setting wins over it.	Text. The browser setting wins over it. On Linux with no display the open step fails with no_display	All sessions
BUILDKITE	Undocumented	Marks a Buildkite CI run. Claude Code uses it for CI detection, deployment detection, and color depth hints.	Text. Any non-empty value counts	All sessions
C9_PID	Undocumented	Marks an AWS Cloud9 workspace. Claude Code reports aws-cloud9 as the environment when it is set.	Any non-empty value. Read directly in deployment detection	All (deployment detection)
C9_USER	Undocumented	Marks an AWS Cloud9 workspace. Claude Code reports aws-cloud9 as the environment when it is set.	Any non-empty value. Read directly in deployment detection	All (deployment detection)
CDPATH	Undocumented	Is the shell cd search path. Claude Code blanks it in cd helper commands and treats it as an unsafe env name to override.	Text	Bash tool, Git and settings env checks
CF_PAGES	Undocumented	Marks Cloudflare Pages. Claude Code reports cloudflare-pages as the deployment environment and counts it as a CI signal.	On or off. Truthy value check	All (deployment detection)
CI	Documented	Marks a CI run for the terminal color level.	Presence test ("CI" in env), any value counts. A CI vendor variable then picks the level	All sessions
CI_NAME	Undocumented	Names the CI vendor. Claude Code checks for codeship when it picks the terminal color depth.	Text. Only the value codeship matters	Terminal color detection (all)
CIRCLECI	Undocumented	Marks a CircleCI run. Claude Code uses it for CI detection, deployment detection, and terminal color depth.	Text. Presence counts	All sessions
CODER	Undocumented	Marks a Coder workspace. The environment detector records deployment coder.	-	-
CODER_WORKSPACE_NAME	Undocumented	Marks a Coder workspace by name. The environment detector records deployment coder.	Text	-
CODESPACES	Undocumented	Marks GitHub Codespaces. The environment detector records deployment codespaces.	-	-
COLORTERM	Undocumented	Reports terminal color support. truecolor or 24bit means 24-bit color.	-	-
COLUMNS	Documented	Gives hook commands the terminal width.	-	-
COMPUTERNAME	Undocumented	The Windows host name. Claude Code uses it as the device name.	-	-
COMSPEC	Undocumented	The Windows command interpreter path. Claude Code uses it as a shell path fallback in environment info.	-	-
ComSpec	Documented	The Windows command interpreter path. The terminal opener uses it for the Command Prompt entry.	-	-
ConEmuANSI	Undocumented	Marks ConEmu. Any of the three ConEmu vars turns on terminal progress reporting.	-	-
ConEmuPID	Undocumented	Marks ConEmu. Any of the three ConEmu vars turns on terminal progress reporting.	-	-
ConEmuTask	Undocumented	Marks ConEmu. The value {cmd::Cmder} also selects Unicode symbols.	-	-
CONTAINER_SANDBOX_MOUNT_POINT	Undocumented	Marks a Windows container. The check turns off the registry sweep.	-	-
COREPACK_ENABLE_AUTO_PIN	Undocumented	Set to 0 at startup so that corepack does not edit package.json.	-	-
CURSOR_TRACE_ID	Undocumented	Marks the Cursor editor. Claude Code uses it to name the terminal host.	Text	-
DAYTONA_WS_ID	Undocumented	Marks a Daytona workspace. The environment detector records deployment daytona.	Text	-
DENO_DEPLOYMENT_ID	Undocumented	Marks Deno Deploy. The environment detector records deployment deno-deploy.	Text	-
DEVPOD	Undocumented	Marks a DevPod workspace. The environment detector records deployment devpod.	-	-
DEVPOD_WORKSPACE_UID	Undocumented	Marks a DevPod workspace by ID. The environment detector records deployment devpod.	-	-
DISPLAY	Undocumented	Tells Claude Code if a local display exists on Linux. With no DISPLAY and no WAYLAND_DISPLAY, it treats the browser open as not possible.	Text. Matched against :N or unix:N forms	Linux. Not set from project env before trust
DRONE	Undocumented	Names Drone CI for the terminal color level.	Presence test, only when CI is set. Gives color level 1	All sessions
DYNO	Undocumented	Heroku sets it. Environment detection reports the deployment platform as heroku when it is non-empty.	Any non-empty value counts	All sessions. Environment detection only
EDITOR	Documented	Names the editor that Claude Code opens for files, for example for /memory. VISUAL wins over it, and the fallback is the first of code, vi, nano found.	Text. Also sent in environment detection as the editor value	Interactive. Not set from project env before trust
FLY_APP_NAME	Undocumented	Fly.io sets it. Environment detection reports the platform as fly.io when it is non-empty.	Text	All sessions. Environment detection only
FLY_MACHINE_ID	Undocumented	Fly.io sets it. Environment detection reports the platform as fly.io when it is non-empty.	Text	All sessions. Environment detection only
FORCE_COLOR	Documented	Forces the color depth. The Bun runtime maps "", 1, true to 16 colors and 2 to 256 colors.	Text. Untrimmed string	All sessions. Not set from project env before trust
GH_CONFIG_DIR	Undocumented	Names the gh config directory. Claude Code checks it for hosts.yml or config.yml to see if gh has a login.	Text. Falls back to XDG_CONFIG_HOME/gh, then ~/.config/gh. Also used in a secrets scan	GitHub features. Not set from project env before trust
GH_HOST	Documented	Names the GitHub host. It picks the enterprise token and is passed to the gh stand-in shim.	Text	GitHub features. Not set from project env before trust
GH_REPO	Undocumented	Names the repository for gh. Claude Code passes it to the gh shim, which uses a host in it to choose the route.	Text	GitHub features. Not set from project env before trust
GITEA_ACTIONS	Undocumented	Names Gitea Actions for the terminal color level.	Presence test, only when CI is set. Gives color level 3 in one helper	All sessions
GITHUB_ACTION_PATH	Undocumented	Path of the running action. Claude Code protects it in the scrub path list and logs the claude-code-action ref.	A path	GitHub Actions. Not set from project env before trust
GITHUB_ACTIONS	Undocumented	Marks a GitHub Actions run. It adds run metadata to telemetry and turns on the subprocess env scrub unless that scrub is set off.	On or off. Truthy parse. CLAUDE_CODE_SUBPROCESS_ENV_SCRUB set to 0, false, no, or off turns the scrub off	GitHub Actions. Not set from project env before trust
GITHUB_ACTOR	Undocumented	Gives a user label for a cache diagnostic. It falls back to USER, USERNAME, then the git email name.	Text. The label drops chars outside a-zA-Z0-9._- and is cut to 64 chars. Telemetry also reads it in Actions	GitHub Actions. Not set from project env before trust
GITHUB_ENV	Undocumented	Path of the runner env file. Claude Code adds it to the protected path list of the subprocess scrub.	Resolved to a path	GitHub Actions. Not set from project env before trust
GITHUB_EVENT_PATH	Undocumented	Path of the event payload file. Claude Code adds it to the protected path list of the subprocess scrub.	A path	GitHub Actions. Not set from project env before trust
GITHUB_WORKSPACE	Undocumented	Path of the workspace. If it differs from the cwd, Claude Code protects its .git hooks and config in the scrub path list.	-	GitHub Actions. Not set from project env before trust
GITLAB_CI	Undocumented	GitLab CI marker. It appears in CI vendor lists of the Bun runtime and the color support code.	Text. Use is by name in lists. No direct Claude Code read was seen	GitLab CI. Not set from project env before trust
GITPOD_WORKSPACE_ID	Undocumented	Gitpod sets it. Environment detection reports the deployment as gitpod when it is non-empty.	Text	All sessions. Environment detection only
GNOME_TERMINAL_SERVICE	Undocumented	Terminal marker for GNOME Terminal. Environment detection records if it is set.	Presence only	Terminal detection
GOOGLE_CLOUD_WORKSTATIONS	Undocumented	Marks Google Cloud Workstations. Environment detection reports gcp-cloud-workstations when it is set.	Presence check	All sessions. Environment detection only
HISTFILE	Undocumented	Gives the shell history path to a context step that reads the shell history for tool usage.	Text. Passed as the history file input. Does not run if the home is a network path	Context gathering. Not set from project env before trust
HOME	Documented	Home directory. Many paths start from it, such as the config and XDG fallback dirs.	Text. Falls back to the OS home dir	All sessions. Not set from project env before trust
HOMEDRIVE	Undocumented	Windows home drive. Claude Code sets it in a child env and uses it to expand paths in a Windows lookup.	Set by Claude Code from the home path for a Windows child env	Windows
HOMEPATH	Undocumented	Windows home path. Claude Code sets it in a child env and uses it to expand paths in a Windows lookup.	Set by Claude Code from the home path for a Windows child env	Windows
HOMESHARE	Undocumented	Windows network home. Claude Code uses it to expand %HOMESHARE% in a Windows registry lookup.	Text	Windows
KUBERNETES_SERVICE_HOST	Undocumented	Detects a Kubernetes pod so Claude Code reports a Kubernetes container runtime.	-	-
NODE_ENV	Documented	Claude Code sets production in the env of some helper child processes. It also lists it in env reports.	-	-
NODE_OPTIONS	Undocumented	Node options. Claude Code adds --max-old-space-size=8192 when CLAUDE_CODE_REMOTE is true.	-	-
NODE_PATH	Documented	Bun runtime module search path. Claude Code removes it from the env of some helper child processes.	A path	-
PATH	Documented	Standard executable search path. Claude Code reads it to find tools and sets it in shell and pwsh child environments.	Text	All sessions. Not set from project env before trust
PATHEXT	Documented	Windows list of executable extensions. Used when Claude Code looks for commands.	Text, .EXE by default. For pwsh child shells Claude Code sets its own value	Windows. Not set from project env before trust
PIP_CERT	Undocumented	Sets the CA bundle path for pip. Claude Code sets it in the egress-proxy child env.	Text. Also in the sandbox CA list	Sessions with the agent proxy or sandbox. Not set from project env before trust
PLAYWRIGHT_BROWSERS_PATH	Undocumented	Is part of the key of the local Chrome search for artifact preview.	Text	Local sessions with artifact preview. Not set from project env before trust
PREFIX	Documented Gated	Gives the Termux install prefix. Claude Code uses $PREFIX/tmp for daemon and socket paths.	Text. Used only when TERMUX_VERSION is set. Else /tmp	Termux (Android). Not set from project env before trust
PROGRAMDATA	Undocumented Gated	Gives the Windows ProgramData folder. Used to find the Start Menu folder and as a protected env name in shell checks.	Text. Looked up as ProgramData, then PROGRAMDATA, then ALLUSERSPROFILE	Windows. Not set from project env before trust
ProgramData	Documented Gated	Gives the Windows ProgramData folder for the sandbox runtime and the Azure Arc token path.	Text. The sandbox throws ProgramData is not set when it is missing	Windows. Not set from project env before trust
ProgramFiles	Documented Gated	Gives the Windows Program Files folder. Used to locate PowerShell and Azure Arc tools.	Text	Windows. Not set from project env before trust
PROJECT_DOMAIN	Undocumented	Marks the host as Glitch in deployment-environment detection.	Text	All platforms. Not set from project env before trust
PWD	Documented	Standard working directory. Claude Code adds it as a session directory when it differs from the original cwd.	Text. Used in startup permission setup and shell-expression checks	All sessions. Not set from project env before trust
RAILWAY_ENVIRONMENT_NAME	Undocumented	Marks the host as Railway in deployment-environment detection.	Text	All platforms. Not set from project env before trust
RAILWAY_SERVICE_NAME	Undocumented	Marks the host as Railway in deployment-environment detection.	Text	All platforms. Not set from project env before trust
RENDER	Undocumented	Marks the host as Render in deployment-environment detection.	Text	All platforms. Not set from project env before trust
REPL_ID	Undocumented	Marks the host as Replit in deployment-environment detection.	Text	All platforms. Not set from project env before trust
REPL_SLUG	Undocumented	Marks the host as Replit in deployment-environment detection.	Text	All platforms. Not set from project env before trust
REQUESTS_CA_BUNDLE	Undocumented	Sets the CA bundle path for Python requests. Claude Code sets it in the egress-proxy and sandbox child env.	Text. Listed with the other CA variables	Sessions with the agent proxy or sandbox. Not set from project env before trust
RUNNER_ENVIRONMENT	Undocumented Gated	GitHub Actions runner kind. github-hosted marks a hosted runner in diagnostics.	Text. Read only when GITHUB_ACTIONS is true	GitHub Actions. Not set from project env before trust
RUNNER_OS	Undocumented Gated	GitHub Actions runner OS. Claude Code reports it in telemetry.	Text. Read only when GITHUB_ACTIONS is true	GitHub Actions. Not set from project env before trust
SESSIONNAME	Undocumented	Windows console session name. Claude Code only records whether it is set, as telemetry about the terminal.	Text. Any non-empty string. No behavior change	All sessions, telemetry only
SPACE_CREATOR_USER_ID	Undocumented	Hugging Face Spaces variable. Claude Code uses it to detect the huggingface-spaces deployment environment for telemetry.	Text. Non-empty string means present	All sessions, telemetry only
SSH_AUTH_SOCK	Undocumented	SSH agent socket. The agent proxy tests whether it is unset before it sets up git access.	Text. Non-empty string. Used with GIT_SSH_COMMAND in a check on the agent proxy git setup	Agent proxy (remote sessions)
SSH_CLIENT	Undocumented	Marks an SSH session. Claude Code uses it to decide not to open a browser and for terminal detection.	Text. Non-empty string means SSH. One of SSH_CONNECTION, SSH_TTY or this on Windows	All sessions
SSH_CONNECTION	Undocumented	Marks an SSH session. Claude Code treats the terminal as remote and skips opening a browser.	Text. Non-empty string. Sets the terminal ssh flag	All sessions
SSH_TTY	Undocumented	Marks an SSH session. Used with SSH_CONNECTION and SSH_CLIENT in Windows terminal checks and in the no-browser check.	Text. Non-empty string means present. Also recorded as hasSshTty in the environment report	All sessions
STY	Undocumented	GNU screen session id. Claude Code uses it to detect a screen multiplexer.	Text. Non-empty string. Sets the multiplexer to screen when TMUX is not set	All sessions
SYSTEMROOT	Undocumented	Windows system directory. Claude Code uses it to find powershell.exe and other Windows tools.	Text. Non-empty string. Falls back to SystemRoot, then to windir, then to C:\Windows	Windows
SystemRoot	Documented	Windows system directory in its usual mixed case. Claude Code reads it as a fallback and sets it in a clean git env.	Text. Non-empty string. On Windows a sanitized env sets it to C:\Windows	Windows
TERM	Documented	Terminal type. Claude Code reads it to pick color level, key dialect, and terminal-feature support.	Text. Non-empty string. Names like xterm-kitty or xterm-ghostty raise the color level to 3	All sessions
TERM_PROGRAM	Documented	Terminal program name. Claude Code reads it to detect vscode, iTerm.app, ghostty, tmux, and others and tune features.	Text. Non-empty string. Used for color level, hyperlinks, clipboard and key support	All sessions
TERM_PROGRAM_VERSION	Undocumented	Terminal program version. Claude Code reads the major version to pick a color level for iTerm.app and a hyperlink check for tmux.	Text. Non-empty string. For example iTerm2 major 3 or later gives true color	All sessions
TERMINAL_EMULATOR	Undocumented	JetBrains sets it to JetBrains-JediTerm. Claude Code uses it to detect a JetBrains IDE terminal.	Compared to JetBrains-JediTerm. On non-macOS it sets the terminal name to pycharm	All sessions, JetBrains terminals
TERMINATOR_UUID	Undocumented	Terminator terminal id. Claude Code records only whether it is set, as a telemetry flag.	Text. Non-empty string means present. No behavior change	All sessions, telemetry only
TF_BUILD	Undocumented	Names Azure Pipelines for the terminal color level.	Presence test together with AGENT_NAME. Gives color level 1 in one helper and 4 in another	All sessions
TILIX_ID	Undocumented	Tilix terminal id. Claude Code records only whether it is set, as a telemetry flag.	Text. Non-empty string means present. No behavior change	All sessions, telemetry only
TMUX	Documented	Set by tmux. Claude Code uses it to detect tmux, to find the tmux socket, and to tune colors and features.	Text. Non-empty string. Also gives a true color step down, and blocks some terminal features inside tmux	All sessions
TMUX_PANE	Undocumented	Set by tmux. Claude Code uses it to find the current pane when it runs tmux commands.	Text. Non-empty string. Needs TMUX as well	Tmux
TRAVIS	Undocumented	Names Travis CI for the terminal color level.	Presence test, only when CI is set. Gives color level 1	All sessions
USER	Documented	Login name. Claude Code uses it as a fallback for the user name, for example in a browser bridge socket name.	Text. Non-empty string. Read when the OS user lookup fails, then USERNAME, then default	All sessions
USERNAME	Undocumented	Windows user name. Claude Code uses it as a name fallback and to spot Windows container users.	Text. Non-empty string. ContainerAdministrator or ContainerUser turns off a registry sweep	Windows
USERPROFILE	Documented	Windows home directory. Claude Code uses it to find Desktop, Documents, Downloads, and IDE lock files, and in WSL path mapping.	Text. Non-empty string. Used on Windows and WSL	Windows and WSL
UV_THREADPOOL_SIZE	Undocumented	Node libuv thread pool size. Claude Code only prints it in MCP HTTP debug logs.	Text. Non-empty string. Shown as default when unset	MCP HTTP transport debug
VERCEL	Undocumented	Vercel variable. Claude Code uses it to detect the vercel deployment environment for telemetry.	On or off. Truthy string	All sessions, telemetry only
VSCODE_GIT_ASKPASS_MAIN	Undocumented	VS Code sets this path. Claude Code checks it to tell Cursor from VS Code and to find remote VS Code servers.	Text. Non-empty string. A path with cursor means Cursor	VS Code and Cursor terminals
VTE_VERSION	Undocumented	VTE terminal version. Claude Code uses it for terminal bug workarounds and hyperlink support.	A number. A value under 5300 gets a workaround for unknown sequence printing. 4400 or more enables a feature	VTE terminals
WAYLAND_DISPLAY	Undocumented	Wayland display name. Claude Code uses it to detect whether a local display exists, and to pick a clipboard tool.	Text. Non-empty string. With no DISPLAY and no WAYLAND_DISPLAY on Linux, it takes no browser or GUI path	Linux
WEBSITE_SITE_NAME	Undocumented	Azure App Service variable. Claude Code uses it to detect the azure-app-service environment for telemetry.	Text. Non-empty string means present	All sessions, telemetry only
WEBSITE_SKU	Undocumented	Azure App Service variable. Claude Code uses it to detect the azure-app-service environment for telemetry.	Text. Non-empty string means present	All sessions, telemetry only
WEZTERM_PANE	Undocumented	WezTerm pane id. Claude Code uses it to exclude WezTerm when it detects a VTE-based terminal.	Text. Non-empty string. Used as a presence check only	All sessions
WINDIR	Undocumented	Windows directory. Claude Code reads it once at load to build the explorer.exe path for a Windows app filter.	Lowercased with a trailing backslash. Also a fallback for powershell.exe path	Windows
WSL_DISTRO_NAME	Undocumented	WSL distro name. Claude Code uses it to detect WSL and to match IDE workspace paths.	Text. Non-empty string. Either this or WSL_INTEROP on Linux sets the platform to wsl	WSL
WSL_INTEROP	Undocumented	WSL interop socket. Claude Code uses it to detect WSL.	Text. Non-empty string. Either this or WSL_DISTRO_NAME on Linux sets the platform to wsl	WSL
WT_SESSION	Undocumented	Windows Terminal session id. Claude Code uses it to detect Windows Terminal for key and link support.	Text. Non-empty string. Enables hyperlinks and some features	Windows Terminal
XTERM_VERSION	Undocumented	Xterm version. Claude Code uses it to tell xterm from a VTE terminal and as a telemetry flag.	Text. Non-empty string. Presence check only	All sessions
ZDOTDIR	Documented	Zsh config directory. Claude Code uses it to find the zsh rc files when it checks for a claude alias.	Text. Non-empty string. Falls back to the home dir	Zsh users
ZED_TERM	Undocumented	Zed terminal marker. Claude Code uses it to detect the Zed terminal for hyperlink and feature support.	Text. Non-empty string. Presence check only	Zed terminal
ZELLIJ	Undocumented	Zellij marker. Claude Code uses it to detect the zellij multiplexer.	Any value other than undefined. Turns off some terminal features	Zellij

How It Works

Many rows here are detection names. Claude Code checks whether a name is set to learn the terminal, CI service, or host. For example, TRAVIS or GITLAB_CI tell it that it runs in CI, which affects the terminal color level. You rarely set these by hand. Set one only to fake or hide a detection result.

Related Pages

• Environment Variables: how Claude Code reads variables and which value wins.
• Bundled Libraries
• Network and Proxy
• UI and Terminal
• Undocumented Items: every item that only the program shows.

Source: the program (variable names found in the 2.1.304 binary) and the Environment Variables page of the official docs.