184| `API_FORCE_IDLE_TIMEOUT` | Override the 5-minute body idle timeout that aborts a streaming model response when no bytes arrive. Set to `0` to turn the timeout off, for example when a slow [gateway](/docs/en/llm-gateway) or local model pauses longer than 5 minutes between chunks, or `1` to keep it on for every provider. When unset, the timeout is active on providers other than the direct Anthropic API, [Claude Platform on AWS](/docs/en/claude-platform-on-aws), and Amazon Bedrock with `CLAUDE_ENABLE_BYTE_WATCHDOG_BEDROCK=1` set. The [stream watchdogs](/docs/en/network-config#streaming-idle-watchdogs) run independently of it and abort a long silent pause even when you set `0` here |184| `API_FORCE_IDLE_TIMEOUT` | Override the 5-minute body idle timeout that aborts a streaming model response when no bytes arrive. Set to `0` to turn the timeout off, for example when a slow [gateway](/docs/en/llm-gateway) or local model pauses longer than 5 minutes between chunks, or `1` to keep it on for every provider. When unset, the timeout is active on providers other than the direct Anthropic API, [Claude Platform on AWS](/docs/en/claude-platform-on-aws), and Amazon Bedrock with `CLAUDE_ENABLE_BYTE_WATCHDOG_BEDROCK=1` set. The [stream watchdogs](/docs/en/network-config#streaming-idle-watchdogs) run independently of it and abort a long silent pause even when you set `0` here |
185| `API_TIMEOUT_MS` | Timeout for API requests in milliseconds (default: 600000, or 10 minutes; maximum: 2147483647). Increase this when requests time out on slow networks or when routing through a proxy. Values above the maximum overflow the underlying timer and cause requests to fail immediately |185| `API_TIMEOUT_MS` | Timeout for API requests in milliseconds (default: 600000, or 10 minutes; maximum: 2147483647). Increase this when requests time out on slow networks or when routing through a proxy. Values above the maximum overflow the underlying timer and cause requests to fail immediately |
186| `AWS_BEARER_TOKEN_BEDROCK` | Amazon Bedrock API key for authentication (see [Amazon Bedrock API keys](https://aws.amazon.com/blogs/machine-learning/accelerate-ai-development-with-amazon-bedrock-api-keys/)) |186| `AWS_BEARER_TOKEN_BEDROCK` | Amazon Bedrock API key for authentication (see [Amazon Bedrock API keys](https://aws.amazon.com/blogs/machine-learning/accelerate-ai-development-with-amazon-bedrock-api-keys/)) |
187| `BASH_DEFAULT_TIMEOUT_MS` | Default timeout for a foreground Bash or PowerShell tool command, in milliseconds (default: 120000, or 2 minutes). A default longer than 30 minutes also becomes the default [time limit for background commands](/docs/en/tools-reference#time-limit-for-background-commands) in unattended sessions. The background time limit requires Claude Code v2.1.285 or later |187| `BASH_DEFAULT_TIMEOUT_MS` | Default timeout for a foreground Bash or PowerShell tool command, in milliseconds (default: 120000, or 2 minutes). A value above the [default time limit for background commands](/docs/en/tools-reference#time-limit-for-background-commands) replaces that default in unattended sessions. The background time limit requires Claude Code v2.1.285 or later |
188| `BASH_MAX_OUTPUT_LENGTH` | Maximum number of characters of bash output that Claude Code reads back into a command's result (default: 30000; maximum: 150000). If you set the [`bashOutputMaxChars`](/docs/en/settings-reference#bashoutputmaxchars) setting, Claude Code ignores this variable. See [Output limits](/docs/en/tools-reference#output-limits) |188| `BASH_MAX_OUTPUT_LENGTH` | Maximum number of characters of bash output that Claude Code reads back into a command's result (default: 30000; maximum: 150000). If you set the [`bashOutputMaxChars`](/docs/en/settings-reference#bashoutputmaxchars) setting, Claude Code ignores this variable. See [Output limits](/docs/en/tools-reference#output-limits) |
189| `BASH_MAX_TIMEOUT_MS` | Maximum timeout the model can set for a foreground Bash or PowerShell tool command, in milliseconds (default: 600000, or 10 minutes). The effective ceiling is the larger of this and `BASH_DEFAULT_TIMEOUT_MS`. An effective ceiling longer than 2 hours also becomes the maximum [time limit for background commands](/docs/en/tools-reference#time-limit-for-background-commands) in unattended sessions. The background time limit requires Claude Code v2.1.285 or later |189| `BASH_MAX_TIMEOUT_MS` | Maximum timeout the model can set for a foreground Bash or PowerShell tool command, in milliseconds (default: 600000, or 10 minutes). The effective ceiling is the larger of this and `BASH_DEFAULT_TIMEOUT_MS`. An effective ceiling longer than 2 hours also becomes the maximum [time limit for background commands](/docs/en/tools-reference#time-limit-for-background-commands) in unattended sessions. The background time limit requires Claude Code v2.1.285 or later |
190| `BETA_TRACING_ENDPOINT` | OTLP/HTTP endpoint for [detailed beta tracing](/docs/en/monitoring-usage#traces-beta): with `ENABLE_BETA_TRACING_DETAILED=1`, logs and traces go there instead of to the configured exporters. Set it in your shell, user settings, or managed settings. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env) |190| `BETA_TRACING_ENDPOINT` | OTLP/HTTP endpoint for [detailed beta tracing](/docs/en/monitoring-usage#traces-beta): with `ENABLE_BETA_TRACING_DETAILED=1`, logs and traces go there instead of to the configured exporters. Set it in your shell, user settings, or managed settings. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env) |
191| `CCR_FORCE_BUNDLE` | Set to `1` to force [`claude --cloud`](/docs/en/claude-code-on-the-web#send-local-repositories-without-github) to bundle and upload your local repository instead of cloning from its remote |191| `CCR_FORCE_BUNDLE` | Set to `1` to force [`claude --cloud`](/docs/en/claude-code-on-the-web#send-local-repositories-without-github) to bundle and upload your local repository instead of cloning from its remote |
192| `CLAUDECODE` | Set to `1` in subprocesses Claude Code spawns (Bash and PowerShell tools, tmux sessions, [hook](/docs/en/hooks) commands, [status line](/docs/en/statusline) commands, stdio [MCP server](/docs/en/mcp) subprocesses). IDE extensions also set this in their integrated terminals. Use to detect when a script is running inside a subprocess spawned by Claude Code. To check whether the current process was spawned directly by a tool call or hook, rather than inside a stdio MCP server that Claude Code started, use `CLAUDE_CODE_CHILD_SESSION` instead |192| `CLAUDECODE` | Set to `1` in subprocesses Claude Code spawns (Bash and PowerShell tools, tmux sessions, [hook](/docs/en/hooks) commands, [status line](/docs/en/statusline) commands, stdio [MCP server](/docs/en/mcp) subprocesses). IDE extensions also set this in their integrated terminals. Use to detect when a script is running inside a subprocess spawned by Claude Code. To check whether the current process was spawned directly by a tool call or hook, rather than inside a stdio MCP server that Claude Code started, use `CLAUDE_CODE_CHILD_SESSION` instead |
193| `CLAUDE_AFK_COUNTDOWN_MS` | How many milliseconds before auto-continue the on-screen countdown appears on an unanswered [`AskUserQuestion`](/docs/en/tools-reference) dialog. Default `20000` (20 seconds), capped at the auto-continue timeout. Has no effect unless auto-continue is on; see the [`askUserQuestionTimeout`](/docs/en/settings-reference#askuserquestiontimeout) setting and `CLAUDE_AFK_TIMEOUT_MS`. Requires Claude Code v2.1.198 or later |193| `CLAUDE_AFK_COUNTDOWN_MS` | How many milliseconds before auto-continue the on-screen countdown appears on an unanswered [`AskUserQuestion`](/docs/en/tools-reference) dialog. Default `20000` (20 seconds), capped at the auto-continue timeout. Has no effect unless auto-continue is on; see the [`askUserQuestionTimeout`](/docs/en/settings-reference#askuserquestiontimeout) setting and `CLAUDE_AFK_TIMEOUT_MS`. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env). Requires Claude Code v2.1.198 or later |
194| `CLAUDE_AFK_TIMEOUT_MS` | How many milliseconds of idle time before an unanswered [`AskUserQuestion`](/docs/en/tools-reference) dialog auto-continues without you. Auto-continue is off by default; opt in with the [`askUserQuestionTimeout`](/docs/en/settings-reference#askuserquestiontimeout) setting. This variable is an override for demos and automated tests: when set, it takes precedence over that setting and turns auto-continue on even when the setting is unset or `never`. Setting `0` doesn't turn the timeout off; it closes the dialog immediately. In v2.1.198 and v2.1.199, auto-continue was on by default with a `60000` (60 seconds) timeout. Requires Claude Code v2.1.198 or later |194| `CLAUDE_AFK_TIMEOUT_MS` | How many milliseconds of idle time before an unanswered [`AskUserQuestion`](/docs/en/tools-reference) dialog auto-continues without you. Auto-continue is off by default; opt in with the [`askUserQuestionTimeout`](/docs/en/settings-reference#askuserquestiontimeout) setting. This variable is an override for demos and automated tests: when set, it takes precedence over that setting and turns auto-continue on even when the setting is unset or `never`. Setting `0` doesn't turn the timeout off; it closes the dialog immediately. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env). Before v2.1.200, auto-continue was on by default with a `60000` (60 seconds) timeout. Requires Claude Code v2.1.198 or later |
195| `CLAUDE_AGENT_SDK_DISABLE_BUILTIN_AGENTS` | Set to `1` to disable all built-in [subagent](/docs/en/sub-agents) types such as Explore and Plan. Only applies in non-interactive mode (the `-p` flag). Useful for SDK users who want a blank slate. This also removes `general-purpose`, the subagent Claude Code runs when an Agent tool call omits `subagent_type`. Such a call then fails with [`subagent_type is required`](/docs/en/errors#subagent-type-is-required) |195| `CLAUDE_AGENT_SDK_DISABLE_BUILTIN_AGENTS` | Set to `1` to disable all built-in [subagent](/docs/en/sub-agents) types such as Explore and Plan. Only applies in non-interactive mode (the `-p` flag). Useful for SDK users who want a blank slate. This also removes `general-purpose`, the subagent Claude Code runs when an Agent tool call omits `subagent_type`. Such a call then fails with [`subagent_type is required`](/docs/en/errors#subagent-type-is-required) |
196| `CLAUDE_AGENT_SDK_MCP_NO_PREFIX` | Set to `1` to skip the `mcp__<server>__` prefix on tool names from SDK-created MCP servers. Tools use their original names. SDK usage only |196| `CLAUDE_AGENT_SDK_MCP_NO_PREFIX` | Set to `1` to skip the `mcp__<server>__` prefix on tool names from SDK-created MCP servers. Tools use their original names. SDK usage only |
197| `CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS` | Stall timeout in milliseconds for subagents. Default `600000` (10 minutes); if you raise `CLAUDE_STREAM_IDLE_TIMEOUT_MS` while the stream watchdog is on, the default rises with it, as [Handle slow or stalled API responses](/docs/en/agent-sdk/typescript#handle-slow-or-stalled-api-responses) describes. The timer resets on each streaming progress event; if no progress arrives within the window, Claude Code aborts the subagent and reports the stall to the parent |197| `CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS` | Stall timeout in milliseconds for subagents. Default `600000` (10 minutes); if you raise `CLAUDE_STREAM_IDLE_TIMEOUT_MS` while the stream watchdog is on, the default rises with it, as [Handle slow or stalled API responses](/docs/en/agent-sdk/typescript#handle-slow-or-stalled-api-responses) describes. The timer resets on each streaming progress event; if no progress arrives within the window, Claude Code aborts the subagent and reports the stall to the parent |
229| `CLAUDE_CODE_CONNECT_TIMEOUT_MS` | Removed in v2.1.186 and now a no-op. Previously set a separate timeout for the connect, TLS, and response-header phase of a streaming API request. Use `API_TIMEOUT_MS` for the per-request timeout. For the response-header phase of a streaming request, see `CLAUDE_STREAM_FIRST_BYTE_TIMEOUT_MS` |229| `CLAUDE_CODE_CONNECT_TIMEOUT_MS` | Removed in v2.1.186 and now a no-op. Previously set a separate timeout for the connect, TLS, and response-header phase of a streaming API request. Use `API_TIMEOUT_MS` for the per-request timeout. For the response-header phase of a streaming request, see `CLAUDE_STREAM_FIRST_BYTE_TIMEOUT_MS` |
230| `CLAUDE_CODE_DEBUG_LOGS_DIR` | Override the debug log file path. Despite the name, this is a file path, not a directory. Requires debug mode to be enabled separately via `--debug`, `/debug`, or the `DEBUG` environment variable: setting this variable alone does not enable logging. The [`--debug-file`](/docs/en/cli-reference#cli-flags) flag does both at once. Defaults to `~/.claude/debug/<session-id>.txt` |230| `CLAUDE_CODE_DEBUG_LOGS_DIR` | Override the debug log file path. Despite the name, this is a file path, not a directory. Requires debug mode to be enabled separately via `--debug`, `/debug`, or the `DEBUG` environment variable: setting this variable alone does not enable logging. The [`--debug-file`](/docs/en/cli-reference#cli-flags) flag does both at once. Defaults to `~/.claude/debug/<session-id>.txt` |
231| `CLAUDE_CODE_DEBUG_LOG_LEVEL` | Minimum log level written to the debug log file. Values: `verbose`, `debug` (default), `info`, `warn`, `error`. Set to `verbose` to include high-volume diagnostics like full status line command output, or raise to `error` to reduce noise |231| `CLAUDE_CODE_DEBUG_LOG_LEVEL` | Minimum log level written to the debug log file. Values: `verbose`, `debug` (default), `info`, `warn`, `error`. Set to `verbose` to include high-volume diagnostics like full status line command output, or raise to `error` to reduce noise |
232| `CLAUDE_CODE_DISABLE_1M_CONTEXT` | Set to `1` to disable [1M context window](/docs/en/model-config#extended-context) support. When set, 1M model variants are unavailable in the model picker, and Claude Code holds sessions on models with a native 1M window, such as [Sonnet 5.5](/docs/en/model-config#sonnet-5-5-and-sonnet-5-context-window) and the Fable models, to a 200K window; see [Extended context](/docs/en/model-config#extended-context) for how the hold is enforced. Useful for enterprise environments with compliance requirements. For its role in correcting the window for an unrecognized `[1m]` model ID, see [Correct the window for a gateway or custom model ID](/docs/en/model-config#correct-the-window-for-a-gateway-or-custom-model-id) |232| `CLAUDE_CODE_DISABLE_1M_CONTEXT` | Set to `1` to turn off [1M context window](/docs/en/model-config#extended-context) support. Claude Code removes `[1m]` model variants from the model picker and holds models that run with the 1M window by default to a 200K window. See [Turn off 1M context](/docs/en/model-config#turn-off-1m-context). Useful for enterprise environments with compliance requirements. For its role in correcting the window for an unrecognized `[1m]` model ID, see [Correct the window for a gateway or custom model ID](/docs/en/model-config#correct-the-window-for-a-gateway-or-custom-model-id) |
233| `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` | Set to `1` to disable [adaptive reasoning](/docs/en/model-config#adjust-effort-level) on Opus 4.6 and Sonnet 4.6 and fall back to the fixed thinking budget controlled by `MAX_THINKING_TOKENS`. Has no effect on [Fable models](/docs/en/model-config#extended-thinking), Sonnet 5 and later, Haiku 5.5, or Opus 4.7 and later, which always use adaptive reasoning |233| `CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING` | Set to `1` to disable [adaptive reasoning](/docs/en/model-config#adjust-effort-level) on Opus 4.6 and Sonnet 4.6 and fall back to the fixed thinking budget controlled by `MAX_THINKING_TOKENS`. Has no effect on [Fable models](/docs/en/model-config#extended-thinking), Sonnet 5 and later, Haiku 5.5, or Opus 4.7 and later, which always use adaptive reasoning |
234| `CLAUDE_CODE_DISABLE_ADMIN_ENV_UNION` | Set to `1` to stop Claude Code from merging [managed settings](/docs/en/managed-settings#precedence-within-the-managed-tier) `env` blocks per key across admin sources, so only the highest-priority source's whole `env` block applies, as before v2.1.223. Set it in the environment that launches Claude Code, since Claude Code ignores a copy delivered through a settings `env` block. Requires Claude Code v2.1.223 or later |234| `CLAUDE_CODE_DISABLE_ADMIN_ENV_UNION` | Set to `1` to stop Claude Code from merging [managed settings](/docs/en/managed-settings#precedence-within-the-managed-tier) `env` blocks per key across admin sources, so only the highest-priority source's whole `env` block applies, as before v2.1.223. Set it in the environment that launches Claude Code, since Claude Code ignores a copy delivered through a settings `env` block. Requires Claude Code v2.1.223 or later |
235| `CLAUDE_CODE_DISABLE_ADVISOR_TOOL` | Set to `1` to disable the [advisor tool](/docs/en/advisor). The `/advisor` command becomes unavailable, any configured `advisorModel` is ignored, and the `--advisor` flag is accepted but has no effect, so existing scripts that pass it continue to work without errors |235| `CLAUDE_CODE_DISABLE_ADVISOR_TOOL` | Set to `1` to disable the [advisor tool](/docs/en/advisor). The `/advisor` command becomes unavailable, any configured `advisorModel` is ignored, and the `--advisor` flag is accepted but has no effect, so existing scripts that pass it continue to work without errors |
236| `CLAUDE_CODE_DISABLE_AGENT_VIEW` | Set to `1` to turn off [background agents and agent view](/docs/en/agent-view): `claude agents`, `--bg`, `/background`, and the on-demand supervisor. Equivalent to the [`disableAgentView`](/docs/en/settings-reference#disableagentview) setting |236| `CLAUDE_CODE_DISABLE_AGENT_VIEW` | Set to `1` to turn off [background agents and agent view](/docs/en/agent-view): `claude agents`, `--bg`, `/background`, and the on-demand supervisor. Equivalent to the [`disableAgentView`](/docs/en/settings-reference#disableagentview) setting |
237| `CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN` | Set to `1` to disable [fullscreen rendering](/docs/en/fullscreen) and use the classic main-screen renderer. The conversation stays in your terminal's native scrollback so `Cmd+f` and tmux copy mode work as usual. Takes precedence over `CLAUDE_CODE_NO_FLICKER` and the [`tui`](/docs/en/settings-reference#tui) setting. You can also switch with `/tui default`. Does not apply to background sessions opened from [agent view](/docs/en/agent-view), which always use fullscreen rendering |237| `CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN` | Set to `1` to disable [fullscreen rendering](/docs/en/fullscreen) and use the classic main-screen renderer. The conversation stays in your terminal's native scrollback so `Cmd+f` and tmux copy mode work as usual. Takes precedence over `CLAUDE_CODE_NO_FLICKER` and the [`tui`](/docs/en/settings-reference#tui) setting. You can also switch with `/tui default`. Does not apply to background sessions opened from [agent view](/docs/en/agent-view), which always use fullscreen rendering |
238| `CLAUDE_CODE_DISABLE_ARTIFACT` | Set to `1` to turn off the [Artifact](/docs/en/artifacts) tool, which publishes session output as a private web page on claude.ai. Once you set it, no settings file turns the tool back on. To turn the tool off from a settings file instead, set [`enableArtifact`](/docs/en/settings-reference#enableartifact) to `false`; the deprecated [`disableArtifact`](/docs/en/settings-reference#disableartifact) key also turns it off |238| `CLAUDE_CODE_DISABLE_ARTIFACT` | Set to `1` to turn off the [Artifact](/docs/en/artifacts) tool, which publishes session output as a private web page on claude.ai. Once you set it, no settings file turns the tool back on. To turn the tool off from a settings file instead, set [`enableArtifact`](/docs/en/settings-reference#enableartifact) to `false`; the deprecated [`disableArtifact`](/docs/en/settings-reference#disableartifact) key also turns it off |
239| `CLAUDE_CODE_DISABLE_ATTACHMENTS` | Set to `1` to disable attachment processing. File mentions with `@` syntax are sent as plain text instead of being expanded into file content |239| `CLAUDE_CODE_DISABLE_ATTACHMENTS` | Set to `1` to disable attachment processing. File mentions with `@` syntax are sent as plain text instead of being expanded into file content. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env) |
240| `CLAUDE_CODE_DISABLE_AUTH_REFRESH_LOCK` | Set to `1` to make a Claude Code process run its [`gcpAuthRefresh`](/docs/en/settings-reference#gcpauthrefresh) or [`awsAuthRefresh`](/docs/en/settings-reference#awsauthrefresh) command itself instead of waiting while another process runs it. Requires Claude Code v2.1.286 or later |240| `CLAUDE_CODE_DISABLE_AUTH_REFRESH_LOCK` | Set to `1` to make a Claude Code process run its [`gcpAuthRefresh`](/docs/en/settings-reference#gcpauthrefresh) or [`awsAuthRefresh`](/docs/en/settings-reference#awsauthrefresh) command itself instead of waiting while another process runs it. Requires Claude Code v2.1.286 or later |
241| `CLAUDE_CODE_DISABLE_AUTO_MEMORY` | Set to `1` to disable [auto memory](/docs/en/memory#auto-memory). Set to `0` to force auto memory on even when `--bare` mode or [`autoMemoryEnabled: false`](/docs/en/settings-reference#automemoryenabled) would otherwise disable it. When disabled, Claude does not create or load auto memory files |241| `CLAUDE_CODE_DISABLE_AUTO_MEMORY` | Set to `1` to disable [auto memory](/docs/en/memory#auto-memory). Set to `0` to force auto memory on even when `--bare` mode or [`autoMemoryEnabled: false`](/docs/en/settings-reference#automemoryenabled) would otherwise disable it. When disabled, Claude does not create or load auto memory files |
242| `CLAUDE_CODE_DISABLE_BACKGROUND_TASKS` | Set to `1` to disable all background task functionality, including the `run_in_background` parameter on Bash and subagent tools, auto-backgrounding, and the Ctrl+B shortcut |242| `CLAUDE_CODE_DISABLE_BACKGROUND_TASKS` | Set to `1` to disable all background task functionality, including the `run_in_background` parameter on Bash and subagent tools, auto-backgrounding, and the Ctrl+B shortcut |
298| `CLAUDE_CODE_FORCE_SESSION_PERSISTENCE` | Set to `1` to force transcript persistence, prompt history, and `claude agents` registration even when this `claude` was launched from inside another Claude Code session. Use when an inherited `CLAUDE_CODE_CHILD_SESSION` value, for example from a `screen` session or a background launcher first started by Claude Code's Bash tool, causes a genuine top-level session to be misclassified as nested. As of v2.1.178, Claude Code detects the tmux case automatically and ignores the inherited marker, so tmux no longer needs this variable. Also honored on v2.1.169 and earlier; has no effect on v2.1.170 and v2.1.171, where the nested-session detection it overrides was removed |298| `CLAUDE_CODE_FORCE_SESSION_PERSISTENCE` | Set to `1` to force transcript persistence, prompt history, and `claude agents` registration even when this `claude` was launched from inside another Claude Code session. Use when an inherited `CLAUDE_CODE_CHILD_SESSION` value, for example from a `screen` session or a background launcher first started by Claude Code's Bash tool, causes a genuine top-level session to be misclassified as nested. As of v2.1.178, Claude Code detects the tmux case automatically and ignores the inherited marker, so tmux no longer needs this variable. Also honored on v2.1.169 and earlier; has no effect on v2.1.170 and v2.1.171, where the nested-session detection it overrides was removed |
299| `CLAUDE_CODE_FORCE_STRIKETHROUGH` | Set to `1` to force strikethrough rendering for `~~text~~` in Claude's responses when your terminal supports it but is not auto-detected, such as over SSH without `TERM_PROGRAM` forwarded. Without this, undetected terminals show the literal `~~` markers instead of rendering the text as strikethrough. Requires Claude Code v2.1.186 or later |299| `CLAUDE_CODE_FORCE_STRIKETHROUGH` | Set to `1` to force strikethrough rendering for `~~text~~` in Claude's responses when your terminal supports it but is not auto-detected, such as over SSH without `TERM_PROGRAM` forwarded. Without this, undetected terminals show the literal `~~` markers instead of rendering the text as strikethrough. Requires Claude Code v2.1.186 or later |
300| `CLAUDE_CODE_FORCE_SYNC_OUTPUT` | Set to `1` to force-enable DEC private mode 2026 [synchronized output](https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036) when your terminal supports it but is not auto-detected. Useful for emulators such as Emacs `eat` that implement BSU/ESU but do not reply to the capability probe. Has no effect under tmux. Unlike `CLAUDE_CODE_NO_FLICKER`, which switches to [fullscreen rendering](/docs/en/fullscreen), this doesn't change the renderer |300| `CLAUDE_CODE_FORCE_SYNC_OUTPUT` | Set to `1` to force-enable DEC private mode 2026 [synchronized output](https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036) when your terminal supports it but is not auto-detected. Useful for emulators such as Emacs `eat` that implement BSU/ESU but do not reply to the capability probe. Has no effect under tmux. Unlike `CLAUDE_CODE_NO_FLICKER`, which switches to [fullscreen rendering](/docs/en/fullscreen), this doesn't change the renderer |
301| `CLAUDE_CODE_FORCE_TERMINAL_IMAGES` | Set to `1` to draw [mod `Image` elements](/docs/en/plugins/mods/reference#elements) as pictures when your terminal draws kitty graphics protocol images with Unicode placeholders but is not auto-detected. See [which terminals Claude Code detects](/docs/en/plugins/mods/gallery#image-and-client) and why it doesn't help inside tmux or screen |
301| `CLAUDE_CODE_FORK_SUBAGENT` | Controls [fork mode](/docs/en/sub-agents#turn-fork-mode-on-or-off), which lets Claude spawn [forked subagents](/docs/en/sub-agents#fork-the-current-conversation) itself and is on by default in interactive sessions only. Set to `1` to turn it on in `claude -p` and the Agent SDK as well, or `0` to turn it off in every kind of session. You can run `/subtask` whether or not fork mode is on. The interactive default requires Claude Code v2.1.232 or later; on earlier versions, set the variable to `1` to turn fork mode on |302| `CLAUDE_CODE_FORK_SUBAGENT` | Controls [fork mode](/docs/en/sub-agents#turn-fork-mode-on-or-off), which lets Claude spawn [forked subagents](/docs/en/sub-agents#fork-the-current-conversation) itself and is on by default in interactive sessions only. Set to `1` to turn it on in `claude -p` and the Agent SDK as well, or `0` to turn it off in every kind of session. You can run `/subtask` whether or not fork mode is on. The interactive default requires Claude Code v2.1.232 or later; on earlier versions, set the variable to `1` to turn fork mode on |
302| `CLAUDE_CODE_FORWARD_SUBAGENT_TEXT` | Set to `1` to emit [subagent](/docs/en/sub-agents) text and thinking blocks in `claude -p --output-format stream-json` output, the same behavior as the [`--forward-subagent-text`](/docs/en/cli-reference#cli-flags) flag. Use the variable when a harness invokes `claude` and can't pass the flag itself. Unlike the flag, which exits with an error outside non-interactive mode with stream-json output, the variable is ignored there so that nested invocations keep working when it's set process-wide. Requires Claude Code v2.1.211 or later |303| `CLAUDE_CODE_FORWARD_SUBAGENT_TEXT` | Set to `1` to emit [subagent](/docs/en/sub-agents) text and thinking blocks in `claude -p --output-format stream-json` output, the same behavior as the [`--forward-subagent-text`](/docs/en/cli-reference#cli-flags) flag. Use the variable when a harness invokes `claude` and can't pass the flag itself. Unlike the flag, which exits with an error outside non-interactive mode with stream-json output, the variable is ignored there so that nested invocations keep working when it's set process-wide. Requires Claude Code v2.1.211 or later |
303| `CLAUDE_CODE_GATEWAY_HINT_HEADERS` | Set to `1` to send the [gateway hint headers](/docs/en/llm-gateway-protocol#gateway-hint-headers), such as `x-claude-code-request-class` and `x-claude-code-compaction`, on a custom proxy or a third-party provider such as Amazon Bedrock or Claude Platform on AWS. Set to `0` to stop sending them on every connection, including a direct connection to the Anthropic API, where Claude Code sends them by default. Requires Claude Code v2.1.273 or later |304| `CLAUDE_CODE_GATEWAY_HINT_HEADERS` | Set to `1` to send the [gateway hint headers](/docs/en/llm-gateway-protocol#gateway-hint-headers), such as `x-claude-code-request-class` and `x-claude-code-compaction`, on a custom proxy or a third-party provider such as Amazon Bedrock or Claude Platform on AWS. Set to `0` to stop sending them on every connection, including a direct connection to the Anthropic API, where Claude Code sends them by default. Requires Claude Code v2.1.273 or later |
321| `CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH` | Number of [subagent layers](/docs/en/sub-agents#let-subagents-spawn-their-own-subagents) allowed below the main conversation (default: 3). At the default, subagents can spawn their own subagents, and a subagent at the third layer can't spawn further; set `1` to turn nesting off. In v2.1.217 through v2.1.218, the default was 1, so a subagent couldn't spawn its own unless you raised the limit; v2.1.219 raised the default to 3. Accepts a positive whole number in plain digits; anything else is ignored, so the limit can be adjusted but not removed. Requires Claude Code v2.1.217 or later |322| `CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH` | Number of [subagent layers](/docs/en/sub-agents#let-subagents-spawn-their-own-subagents) allowed below the main conversation (default: 3). At the default, subagents can spawn their own subagents, and a subagent at the third layer can't spawn further; set `1` to turn nesting off. In v2.1.217 through v2.1.218, the default was 1, so a subagent couldn't spawn its own unless you raised the limit; v2.1.219 raised the default to 3. Accepts a positive whole number in plain digits; anything else is ignored, so the limit can be adjusted but not removed. Requires Claude Code v2.1.217 or later |
322| `CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY` | Maximum number of read-only tools and subagents that can execute in parallel (default: 10). Higher values increase parallelism but consume more resources |323| `CLAUDE_CODE_MAX_TOOL_USE_CONCURRENCY` | Maximum number of read-only tools and subagents that can execute in parallel (default: 10). Higher values increase parallelism but consume more resources |
323| `CLAUDE_CODE_MAX_TURNS` | Cap the number of agentic turns when no explicit limit is passed. Equivalent to passing [`--max-turns`](/docs/en/cli-reference#cli-flags), which takes precedence when both are set. A value that is not a positive integer is rejected at startup with an error rather than treated as no cap |324| `CLAUDE_CODE_MAX_TURNS` | Cap the number of agentic turns when no explicit limit is passed. Equivalent to passing [`--max-turns`](/docs/en/cli-reference#cli-flags), which takes precedence when both are set. A value that is not a positive integer is rejected at startup with an error rather than treated as no cap |
324| `CLAUDE_CODE_MAX_WEB_SEARCHES_PER_SESSION` | Cap on the total number of [WebSearch](/docs/en/tools-reference#websearch-tool-behavior) calls one session can make (default: 200). When Claude reaches the cap, further WebSearch calls return a notice telling it to continue with the information it already gathered. Accepts a positive whole number with no upper bound. Anything else is ignored and the default applies, so the cap can be raised but not turned off. Requires Claude Code v2.1.212 or later |325| `CLAUDE_CODE_MAX_WEB_SEARCHES_PER_SESSION` | Cap on [WebSearch](/docs/en/tools-reference#session-search-limit) calls (default: 200). When Claude reaches the cap, further WebSearch calls return a notice telling it to continue with the information it already gathered. Accepts a positive whole number with no upper bound. Anything else is ignored and the default applies, so the cap can be raised but not turned off. Requires Claude Code v2.1.212 or later |
325| `CLAUDE_CODE_MCP_ALLOWLIST_ENV` | Set to `1` to spawn stdio MCP servers with only a safe baseline environment plus the server's configured `env`, instead of inheriting your shell environment |326| `CLAUDE_CODE_MCP_ALLOWLIST_ENV` | Set to `1` to spawn stdio MCP servers with only a safe baseline environment plus the server's configured `env`, instead of inheriting your shell environment |
326| `CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS` | Elapsed time in milliseconds before a still-running MCP tool call [moves to a background task](/docs/en/mcp#automatic-backgrounding-of-long-tool-calls) (default: 120000, or 2 minutes). Set to `0` to turn automatic backgrounding off. Requires Claude Code v2.1.212 or later |327| `CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS` | Elapsed time in milliseconds before a still-running MCP tool call [moves to a background task](/docs/en/mcp#automatic-backgrounding-of-long-tool-calls) (default: 120000, or 2 minutes). Set to `0` to turn automatic backgrounding off. Requires Claude Code v2.1.212 or later |
327| `CLAUDE_CODE_MCP_STARTUP_WAIT_MS` | How long in milliseconds the first turn of a [non-interactive](/docs/en/headless) session waits for MCP servers that are still connecting, in place of the default [first-turn wait](/docs/en/agent-sdk/mcp#connection-timing). When set, the wait covers every pending server. Set to `0` to skip the wait. A [`--permission-prompt-tool`](/docs/en/cli-reference#cli-flags) server keeps its own `MCP_TIMEOUT` wait regardless of the value. Requires Claude Code v2.1.274 or later |328| `CLAUDE_CODE_MCP_STARTUP_WAIT_MS` | How long in milliseconds the first turn of a [non-interactive](/docs/en/headless) session waits for MCP servers that are still connecting, in place of the default [first-turn wait](/docs/en/agent-sdk/mcp#connection-timing). When set, the wait covers every pending server. Set to `0` to skip the wait. A [`--permission-prompt-tool`](/docs/en/cli-reference#cli-flags) server keeps its own `MCP_TIMEOUT` wait regardless of the value. Requires Claude Code v2.1.274 or later |
331| `CLAUDE_CODE_NATIVE_CURSOR` | Set to `1` to show the terminal's own cursor at the input caret instead of a drawn block. The cursor respects the terminal's blink, shape, and focus settings. Setting `0` reads the same as leaving the variable unset, so it doesn't bring the drawn block back in a session where the terminal's own cursor is already on |332| `CLAUDE_CODE_NATIVE_CURSOR` | Set to `1` to show the terminal's own cursor at the input caret instead of a drawn block. The cursor respects the terminal's blink, shape, and focus settings. Setting `0` reads the same as leaving the variable unset, so it doesn't bring the drawn block back in a session where the terminal's own cursor is already on |
332| `CLAUDE_CODE_NEW_INIT` | Set to `1` to make `/init` run an interactive setup flow. The flow asks which files to generate, including CLAUDE.md, skills, and hooks, before exploring the codebase and writing them. Without this variable, `/init` generates a CLAUDE.md automatically without prompting |333| `CLAUDE_CODE_NEW_INIT` | Set to `1` to make `/init` run an interactive setup flow. The flow asks which files to generate, including CLAUDE.md, skills, and hooks, before exploring the codebase and writing them. Without this variable, `/init` generates a CLAUDE.md automatically without prompting |
333| `CLAUDE_CODE_NONBLOCKING_STDOUT` | Set to `1` to write terminal output through a second non-blocking file descriptor, so a terminal that stops reading, such as a paused tmux control-mode pane or a stalled SSH connection, can't freeze Claude Code mid-session. Applies on macOS, Linux, and WSL when stdout is a terminal. Requires Claude Code v2.1.261 or later |334| `CLAUDE_CODE_NONBLOCKING_STDOUT` | Set to `1` to write terminal output through a second non-blocking file descriptor, so a terminal that stops reading, such as a paused tmux control-mode pane or a stalled SSH connection, can't freeze Claude Code mid-session. Applies on macOS, Linux, and WSL when stdout is a terminal. Requires Claude Code v2.1.261 or later |
334| `CLAUDE_CODE_NONSTREAMING_TIMEOUT_RETRIES` | Limit how many times Claude Code re-sends a [non-streaming request](/docs/en/errors#streaming-response-ended-before-any-complete-data-was-received) that times out. With `0`, the request fails on the first timeout. Unset by default, so `CLAUDE_CODE_MAX_RETRIES` limits these re-sends. See [Tune retry behavior](/docs/en/errors#tune-retry-behavior) for the timeout. Requires Claude Code v2.1.285 or later |335| `CLAUDE_CODE_NONSTREAMING_TIMEOUT_RETRIES` | Limit how many times Claude Code re-sends a [non-streaming request](/docs/en/errors#streaming-response-ended-before-any-complete-data-was-received) that times out. With `0`, the request fails on the first timeout. See [Tune retry behavior](/docs/en/errors#tune-retry-behavior) for the timeout. Requires Claude Code v2.1.285 or later |
335| `CLAUDE_CODE_NO_FLICKER` | Set to `1` to enable [fullscreen rendering](/docs/en/fullscreen), a research preview that reduces flicker and keeps memory flat in long conversations. Overrides the [`tui`](/docs/en/settings-reference#tui) setting; you can also switch with `/tui fullscreen` |336| `CLAUDE_CODE_NO_FLICKER` | Set to `1` to enable [fullscreen rendering](/docs/en/fullscreen), a research preview that reduces flicker and keeps memory flat in long conversations. Overrides the [`tui`](/docs/en/settings-reference#tui) setting; you can also switch with `/tui fullscreen` |
336| `CLAUDE_CODE_OAUTH_REFRESH_TOKEN` | OAuth refresh token for Claude.ai authentication. When set, `claude auth login` exchanges this token directly instead of opening a browser. Requires `CLAUDE_CODE_OAUTH_SCOPES`. Useful for provisioning authentication in automated environments |337| `CLAUDE_CODE_OAUTH_REFRESH_TOKEN` | OAuth refresh token for Claude.ai authentication. When set, `claude auth login` exchanges this token directly instead of opening a browser. Requires `CLAUDE_CODE_OAUTH_SCOPES`. Useful for provisioning authentication in automated environments |
337| `CLAUDE_CODE_OAUTH_SCOPES` | Space-separated OAuth scopes the refresh token was issued with, such as `"user:profile user:inference user:sessions:claude_code"`. Required when `CLAUDE_CODE_OAUTH_REFRESH_TOKEN` is set |338| `CLAUDE_CODE_OAUTH_SCOPES` | Space-separated OAuth scopes the refresh token was issued with, such as `"user:profile user:inference user:sessions:claude_code"`. Required when `CLAUDE_CODE_OAUTH_REFRESH_TOKEN` is set |
342| `CLAUDE_CODE_OTEL_FLUSH_TIMEOUT_MS` | Timeout in milliseconds for flushing pending OpenTelemetry spans (default: 5000). See [Monitoring](/docs/en/monitoring-usage) |343| `CLAUDE_CODE_OTEL_FLUSH_TIMEOUT_MS` | Timeout in milliseconds for flushing pending OpenTelemetry spans (default: 5000). See [Monitoring](/docs/en/monitoring-usage) |
343| `CLAUDE_CODE_OTEL_HEADERS_HELPER_DEBOUNCE_MS` | Interval for refreshing dynamic OpenTelemetry headers in milliseconds (default: 1740000 / 29 minutes). See [Dynamic headers](/docs/en/monitoring-usage#dynamic-headers) |344| `CLAUDE_CODE_OTEL_HEADERS_HELPER_DEBOUNCE_MS` | Interval for refreshing dynamic OpenTelemetry headers in milliseconds (default: 1740000 / 29 minutes). See [Dynamic headers](/docs/en/monitoring-usage#dynamic-headers) |
344| `CLAUDE_CODE_OTEL_SHUTDOWN_TIMEOUT_MS` | Timeout in milliseconds for the OpenTelemetry exporter to finish on shutdown (default: 2000). Increase if metrics are dropped at exit. See [Monitoring](/docs/en/monitoring-usage) |345| `CLAUDE_CODE_OTEL_SHUTDOWN_TIMEOUT_MS` | Timeout in milliseconds for the OpenTelemetry exporter to finish on shutdown (default: 2000). Increase if metrics are dropped at exit. See [Monitoring](/docs/en/monitoring-usage) |
346| `CLAUDE_CODE_OVERLOADED_RETRY_BASE_DELAY_MS` | Starting delay in milliseconds, in place of the default 500, of the exponential backoff between [automatic retries](/docs/en/errors#tune-retry-behavior) of a request that the API rejects with a `529` overloaded error. Raise it to spread the retries over a longer window when the API is at capacity. Give whole milliseconds from 500 to 32000 in plain digits; Claude Code treats any other value as unset. Has no effect when `CLAUDE_CODE_RETRY_WATCHDOG` is set to `1`, or when the rejected request was sent in [fast mode](/docs/en/fast-mode#handle-rate-limits). Requires Claude Code v2.1.292 or later |
345| `CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE` | Set to `1` to let Claude Code run your package manager's upgrade command in the background when a new version is available. Applies to Homebrew and WinGet installations. Other package managers continue to show the upgrade command without running it. See [Auto updates](/docs/en/setup#auto-updates) |347| `CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE` | Set to `1` to let Claude Code run your package manager's upgrade command in the background when a new version is available. Applies to Homebrew and WinGet installations. Other package managers continue to show the upgrade command without running it. See [Auto updates](/docs/en/setup#auto-updates) |
346| `CLAUDE_CODE_PERFORCE_MODE` | Set to `1` to enable Perforce-aware write protection. When set, Edit, Write, and NotebookEdit fail with a `p4 edit <file>` hint if the target file lacks the owner-write bit, which Perforce clears on synced files until `p4 edit` opens them. This prevents Claude Code from bypassing Perforce change tracking |348| `CLAUDE_CODE_PERFORCE_MODE` | Set to `1` to enable Perforce-aware write protection. When set, Edit, Write, and NotebookEdit fail with a `p4 edit <file>` hint if the target file lacks the owner-write bit, which Perforce clears on synced files until `p4 edit` opens them. This prevents Claude Code from bypassing Perforce change tracking |
347| `CLAUDE_CODE_PLUGIN_CACHE_DIR` | Override the plugins root directory. Despite the name, this sets the parent directory, not the cache itself: marketplaces and the plugin cache live in subdirectories under this path. Defaults to `~/.claude/plugins` |349| `CLAUDE_CODE_PLUGIN_CACHE_DIR` | Override the plugins root directory. Despite the name, this sets the parent directory, not the cache itself: marketplaces and the plugin cache live in subdirectories under this path. Defaults to `~/.claude/plugins` |
352| `CLAUDE_CODE_PLUGIN_PREFER_HTTPS` | Set to `1` to clone GitHub `owner/repo` shorthand sources over HTTPS instead of SSH. Applies to plugin install and update, and to `/plugin marketplace add` and `update`. Useful in CI runners, containers, or any environment without a configured SSH key for `github.com` |354| `CLAUDE_CODE_PLUGIN_PREFER_HTTPS` | Set to `1` to clone GitHub `owner/repo` shorthand sources over HTTPS instead of SSH. Applies to plugin install and update, and to `/plugin marketplace add` and `update`. Useful in CI runners, containers, or any environment without a configured SSH key for `github.com` |
353| `CLAUDE_CODE_PLUGIN_SEED_DIR` | Path to one or more read-only plugin seed directories, separated by `:` on Unix or `;` on Windows. Use this to bundle a pre-populated plugins directory into a container image. Claude Code registers marketplaces from these directories at startup and uses pre-cached plugins without re-cloning. See [Pre-populate plugins for containers](/docs/en/plugins/org#seed-containers-and-ci) |355| `CLAUDE_CODE_PLUGIN_SEED_DIR` | Path to one or more read-only plugin seed directories, separated by `:` on Unix or `;` on Windows. Use this to bundle a pre-populated plugins directory into a container image. Claude Code registers marketplaces from these directories at startup and uses pre-cached plugins without re-cloning. See [Pre-populate plugins for containers](/docs/en/plugins/org#seed-containers-and-ci) |
354| `CLAUDE_CODE_POWERSHELL_RESPECT_EXECUTION_POLICY` | Set to `1` to stop Claude Code from passing `-ExecutionPolicy Bypass` when spawning PowerShell for tool calls, hooks, and status line commands, and respect the machine's effective execution policy instead. By default Claude Code bypasses execution policy at process scope so `.ps1` scripts and module imports work on default-Restricted Windows installs. Process-scope bypass never overrides Group Policy `MachinePolicy` or `UserPolicy` regardless of this setting |356| `CLAUDE_CODE_POWERSHELL_RESPECT_EXECUTION_POLICY` | Set to `1` to stop Claude Code from passing `-ExecutionPolicy Bypass` when spawning PowerShell for tool calls, hooks, and status line commands, and respect the machine's effective execution policy instead. By default Claude Code bypasses execution policy at process scope so `.ps1` scripts and module imports work on default-Restricted Windows installs. Process-scope bypass never overrides Group Policy `MachinePolicy` or `UserPolicy` regardless of this setting |
355| `CLAUDE_CODE_PRINT_BG_WAIT_CEILING_MS` | Ceiling in milliseconds on idle waiting for background work, such as subagents and workflows, after the final turn in [non-interactive mode](/docs/en/headless#background-tasks-at-exit) with the `-p` flag. Idle waiting starts over each time Claude takes a turn to handle a background result. Default: `600000`, or 10 minutes. When idle waiting reaches the ceiling, Claude Code stops waiting for the remaining background tasks and exits. Set to `0` to wait indefinitely. This cap is separate from the five-second grace period that applies to plain background shells. Requires Claude Code v2.1.182 or later |357| `CLAUDE_CODE_PRINT_BG_WAIT_CEILING_MS` | Ceiling in milliseconds on idle waiting for background work, such as subagents and workflows, after the final turn in [non-interactive mode](/docs/en/headless#background-tasks-at-exit) with the `-p` flag. Idle waiting starts over each time Claude takes a turn to handle a background result. Default: `600000`, or 10 minutes. When idle waiting reaches the ceiling, Claude Code stops waiting for the remaining background tasks. A running background command that the main conversation started holds the run open past it. Set to `0` to wait indefinitely. Requires Claude Code v2.1.182 or later |
356| `CLAUDE_CODE_PROCESS_WRAPPER` | Launch the processes Claude Code starts from its own binary, such as the background service that hosts [agent view](/docs/en/agent-view) sessions, through a corporate launcher given as an argv prefix like `/opt/corp/launcher`. Set it in the `env` block of user or [managed settings](/docs/en/managed-settings), not as a shell export, so the detached background service inherits it; project and local settings can't set it. Equivalent to the [`processWrapper` setting](/docs/en/settings-reference#processwrapper), which requires Claude Code v2.1.210 or later; this variable takes precedence when both are set. The VS Code extension configures its own launcher separately through its `claudeProcessWrapper` setting. Ignored on Windows. See [Run Claude Code behind a corporate launcher](/docs/en/corporate-launcher) for the value format, what the launcher covers, and the contract the launcher must satisfy. Requires Claude Code v2.1.208 or later |358| `CLAUDE_CODE_PROCESS_WRAPPER` | Launch the processes Claude Code starts from its own binary, such as the background service that hosts [agent view](/docs/en/agent-view) sessions, through a corporate launcher given as an argv prefix like `/opt/corp/launcher`. Set it in the `env` block of user or [managed settings](/docs/en/managed-settings), not as a shell export, so the detached background service inherits it; project and local settings can't set it. Equivalent to the [`processWrapper` setting](/docs/en/settings-reference#processwrapper), which requires Claude Code v2.1.210 or later; this variable takes precedence when both are set. The VS Code extension configures its own launcher separately through its `claudeProcessWrapper` setting. Ignored on Windows. See [Run Claude Code behind a corporate launcher](/docs/en/corporate-launcher) for the value format, what the launcher covers, and the contract the launcher must satisfy. Requires Claude Code v2.1.208 or later |
357| `CLAUDE_CODE_PROJECT_DIR_NAME` | Set together with `CLAUDE_CONFIG_DIR` to choose the `projects/` directory name Claude Code stores that session's transcripts and auto memory under, in place of one derived from the working directory path. For example, starting Claude Code with `CLAUDE_CONFIG_DIR=/srv/tenant-a CLAUDE_CODE_PROJECT_DIR_NAME=work claude` stores them under `/srv/tenant-a/projects/work/`. Claude Code ignores this variable when `CLAUDE_CONFIG_DIR` is unset, and reads it only from the environment you start `claude` from, never from a [settings file `env` block](#in-settings-files). See [Name the project directory yourself](/docs/en/sessions#name-the-project-directory-yourself). Requires Claude Code v2.1.234 or later |359| `CLAUDE_CODE_PROJECT_DIR_NAME` | Set together with `CLAUDE_CONFIG_DIR` to choose the `projects/` directory name Claude Code stores that session's transcripts and auto memory under, in place of one derived from the working directory path. For example, starting Claude Code with `CLAUDE_CONFIG_DIR=/srv/tenant-a CLAUDE_CODE_PROJECT_DIR_NAME=work claude` stores them under `/srv/tenant-a/projects/work/`. Claude Code ignores this variable when `CLAUDE_CONFIG_DIR` is unset, and reads it only from the environment you start `claude` from, never from a [settings file `env` block](#in-settings-files). See [Name the project directory yourself](/docs/en/sessions#name-the-project-directory-yourself). Requires Claude Code v2.1.234 or later |
358| `CLAUDE_CODE_PROMPT_CACHE_TTL` | Set `5m` or `1h`, the only values Claude Code accepts, to choose the [prompt cache TTL](/docs/en/prompt-caching#cache-lifetime) for the main conversation: your interactive, `-p`, and SDK turns, plus the helpers that run inline with them. Takes precedence over the `promptCacheTtl` setting and over `ENABLE_PROMPT_CACHING_1H`, and `FORCE_PROMPT_CACHING_5M` overrides it. The API bills 1-hour cache writes at a higher rate. Requires Claude Code v2.1.242 or later |360| `CLAUDE_CODE_PROMPT_CACHE_TTL` | Set `5m` or `1h`, the only values Claude Code accepts, to choose the [prompt cache TTL](/docs/en/prompt-caching#cache-lifetime) for the main conversation: your interactive, `-p`, and SDK turns, plus the helpers that run inline with them. Takes precedence over the `promptCacheTtl` setting and over `ENABLE_PROMPT_CACHING_1H`, and `FORCE_PROMPT_CACHING_5M` overrides it. The API bills 1-hour cache writes at a higher rate. Requires Claude Code v2.1.242 or later |
375| `CLAUDE_CODE_SHELL` | Set the shell Claude Code uses to run Bash tool commands. Accepts a path to a `bash` or `zsh` binary, for example `/opt/homebrew/bin/bash`. Other shells such as `fish` are not supported. If the value is not a working `bash` or `zsh` path, Claude Code ignores it and falls back to auto-detection. Auto-detection uses your `$SHELL` when it points to `bash` or `zsh`, otherwise it picks the first working `zsh` then `bash` found on your `PATH` and standard install locations |377| `CLAUDE_CODE_SHELL` | Set the shell Claude Code uses to run Bash tool commands. Accepts a path to a `bash` or `zsh` binary, for example `/opt/homebrew/bin/bash`. Other shells such as `fish` are not supported. If the value is not a working `bash` or `zsh` path, Claude Code ignores it and falls back to auto-detection. Auto-detection uses your `$SHELL` when it points to `bash` or `zsh`, otherwise it picks the first working `zsh` then `bash` found on your `PATH` and standard install locations |
376| `CLAUDE_CODE_SHELL_PREFIX` | Command prefix that wraps shell commands Claude Code spawns: Bash tool calls, [hook](/docs/en/hooks) commands, [status line](/docs/en/statusline) commands, and stdio [MCP server](/docs/en/mcp) startup commands. PowerShell hooks and exec-form hooks run without the prefix. Useful for logging or auditing. Setting a bare executable path such as `/path/to/logger.sh` runs each command as `/path/to/logger.sh '<command>'`. The wrapper receives the command line as a single shell-quoted argument in `$1`, so the wrapper must re-evaluate `$1` with a shell, for example `exec bash -c "$1"`. Treating `$1` as a bare executable path breaks stdio MCP servers that pass arguments such as `npx -y <package>`. For Bash tool calls, `$1` contains the full shell invocation Claude Code assembles, including environment setup, not only the command Claude ran |378| `CLAUDE_CODE_SHELL_PREFIX` | Command prefix that wraps shell commands Claude Code spawns: Bash tool calls, [hook](/docs/en/hooks) commands, [status line](/docs/en/statusline) commands, and stdio [MCP server](/docs/en/mcp) startup commands. PowerShell hooks and exec-form hooks run without the prefix. Useful for logging or auditing. Setting a bare executable path such as `/path/to/logger.sh` runs each command as `/path/to/logger.sh '<command>'`. The wrapper receives the command line as a single shell-quoted argument in `$1`, so the wrapper must re-evaluate `$1` with a shell, for example `exec bash -c "$1"`. Treating `$1` as a bare executable path breaks stdio MCP servers that pass arguments such as `npx -y <package>`. For Bash tool calls, `$1` contains the full shell invocation Claude Code assembles, including environment setup, not only the command Claude ran |
377| `CLAUDE_CODE_SIMPLE` | Set to `1` to run with a minimal system prompt and only the Bash, file read, and file edit tools. MCP tools from `--mcp-config` are still available. Disables auto-discovery of hooks, skills, custom commands, subagents, installed plugins, MCP servers, auto memory, and CLAUDE.md. Skills in a directory you pass with `--add-dir` still load. OAuth tokens and keychain credentials are not read, so Anthropic authentication must come from `ANTHROPIC_API_KEY` or an `apiKeyHelper` in `--settings`. Equivalent to passing [`--bare`](/docs/en/headless#start-faster-with-bare-mode) |379| `CLAUDE_CODE_SIMPLE` | Set to `1` to run with a minimal system prompt and only the Bash, file read, and file edit tools. MCP tools from `--mcp-config` are still available. Disables auto-discovery of hooks, skills, custom commands, subagents, installed plugins, MCP servers, auto memory, and CLAUDE.md. Skills in a directory you pass with `--add-dir` still load. OAuth tokens and keychain credentials are not read, so Anthropic authentication must come from `ANTHROPIC_API_KEY` or an `apiKeyHelper` in `--settings`. Equivalent to passing [`--bare`](/docs/en/headless#start-faster-with-bare-mode) |
378| `CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT` | Set to `1` to use a shorter system prompt and abbreviated tool descriptions on any model. Set to `0`, `false`, `no`, or `off` to opt out even on models where the experiment or server configuration would otherwise enable it. The full tool set, hooks, MCP servers, and CLAUDE.md discovery remain enabled |380| `CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT` | Choose between Claude Code's full system prompt and a shorter one with abbreviated tool descriptions. When unset, Haiku 4.5, Sonnet 5, Opus 4.7, and earlier models in those families use the full prompt by default, and newer models use the shorter one. Set to `1` to use the shorter prompt on any model. Set to `0`, `false`, `no`, or `off` to use the full prompt on any model, even where an experiment or server configuration would otherwise select the shorter one. Either prompt keeps the full tool set, hooks, MCP servers, and CLAUDE.md discovery |
379| `CLAUDE_CODE_SKIP_ANTHROPIC_AWS_AUTH` | Skip client-side authentication for [Claude Platform on AWS](/docs/en/claude-platform-on-aws), for gateways that sign requests themselves |381| `CLAUDE_CODE_SKIP_ANTHROPIC_AWS_AUTH` | Skip client-side authentication for [Claude Platform on AWS](/docs/en/claude-platform-on-aws), for gateways that sign requests themselves |
380| `CLAUDE_CODE_SKIP_AWS_CRED_CACHE` | Set to `1` to turn off the in-process cache of credentials resolved from the AWS default credential provider chain, so Claude Code resolves the chain on every API request. With the cache off, an SSO-backed profile requests credentials from IAM Identity Center on every request. See [credential caching and resolution timeout](/docs/en/amazon-bedrock#credential-caching-and-resolution-timeout). Requires Claude Code v2.1.207 or later |382| `CLAUDE_CODE_SKIP_AWS_CRED_CACHE` | Set to `1` to turn off the in-process cache of credentials resolved from the AWS default credential provider chain, so Claude Code resolves the chain on every API request. With the cache off, an SSO-backed profile requests credentials from IAM Identity Center on every request. See [credential caching and resolution timeout](/docs/en/amazon-bedrock#credential-caching-and-resolution-timeout). Requires Claude Code v2.1.207 or later |
381| `CLAUDE_CODE_SKIP_BEDROCK_AUTH` | Skip AWS authentication for Amazon Bedrock (for example, when using an LLM gateway) |383| `CLAUDE_CODE_SKIP_BEDROCK_AUTH` | Skip AWS authentication for Amazon Bedrock (for example, when using an LLM gateway) |
405| `CLAUDE_CODE_TOOL_MEMORY_CGROUP_EXCLUDE` | On Linux and WSL, set to a comma-separated list of the kinds of processes Claude Code [excludes from the tool memory cap](/docs/en/tools-reference#memory-limit-on-linux-and-wsl), such as `mcp` or `lsp`. Set `none` to cap every kind, or `all-new` to cap only Bash, PowerShell, and Monitor tool commands. Claude Code keeps Bash, PowerShell, and Monitor tool commands under the cap whatever you list. Requires Claude Code v2.1.246 or later |407| `CLAUDE_CODE_TOOL_MEMORY_CGROUP_EXCLUDE` | On Linux and WSL, set to a comma-separated list of the kinds of processes Claude Code [excludes from the tool memory cap](/docs/en/tools-reference#memory-limit-on-linux-and-wsl), such as `mcp` or `lsp`. Set `none` to cap every kind, or `all-new` to cap only Bash, PowerShell, and Monitor tool commands. Claude Code keeps Bash, PowerShell, and Monitor tool commands under the cap whatever you list. Requires Claude Code v2.1.246 or later |
406| `CLAUDE_CODE_TOOL_MEMORY_LIMIT` | On Linux and WSL, set to a size such as `4G` to [cap the memory that Bash and PowerShell tool commands can use](/docs/en/tools-reference#memory-limit-on-linux-and-wsl), and Monitor tool commands on v2.1.246 or later. Write the size in plain digits, alone for a number of bytes or with a `K`, `M`, `G`, or `T` suffix. Set `0` or `off` to turn the cap off. Once the first process Claude Code starts has turned the cap on or off, a changed value takes effect the next time you launch `claude`. Requires Claude Code v2.1.233 or later |408| `CLAUDE_CODE_TOOL_MEMORY_LIMIT` | On Linux and WSL, set to a size such as `4G` to [cap the memory that Bash and PowerShell tool commands can use](/docs/en/tools-reference#memory-limit-on-linux-and-wsl), and Monitor tool commands on v2.1.246 or later. Write the size in plain digits, alone for a number of bytes or with a `K`, `M`, `G`, or `T` suffix. Set `0` or `off` to turn the cap off. Once the first process Claude Code starts has turned the cap on or off, a changed value takes effect the next time you launch `claude`. Requires Claude Code v2.1.233 or later |
407| `CLAUDE_CODE_TRANSCRIPT_LOCAL_GC` | Set to `1` to limit how large the [transcript file](/docs/en/sessions#where-transcripts-are-stored) of a long `-p` or Agent SDK session grows. After each compaction, once the file is larger than 5 MB, Claude Code removes the history from before that compaction. Resuming the session restores the same conversation whether or not the file was trimmed. Set it in the environment you start Claude Code from, since a settings `env` block can't turn it on. Requires Claude Code v2.1.287 or later |409| `CLAUDE_CODE_TRANSCRIPT_LOCAL_GC` | Set to `1` to limit how large the [transcript file](/docs/en/sessions#where-transcripts-are-stored) of a long `-p` or Agent SDK session grows. After each compaction, once the file is larger than 5 MB, Claude Code removes the history from before that compaction. Resuming the session restores the same conversation whether or not the file was trimmed. Set it in the environment you start Claude Code from, since a settings `env` block can't turn it on. Requires Claude Code v2.1.287 or later |
408| `CLAUDE_CODE_USER_DIALOG_TIMEOUT_MS` | Deadline in milliseconds before Claude Code cancels a dialog it forwards to a remote client such as a [Remote Control](/docs/en/remote-control) or SDK host, or the approval dialog for a [held cross-session message](/docs/en/cross-session-messaging#control-inbound-messages); permission prompts and `AskUserQuestion` questions use their own flows and aren't governed by it. On Claude Code v2.1.236 or later, it also bounds the mid-session [Fable usage-credits consent prompt](/docs/en/model-config#fable-and-usage-credits) in a session that may be running unattended. [Control inbound messages](/docs/en/cross-session-messaging#control-inbound-messages) and [non-interactive sessions](/docs/en/cross-session-messaging#non-interactive-sessions) cover the full held-message expiry rules, including the cases where the deadline doesn't apply. Overrides the [`dialogExpiry`](/docs/en/settings-reference#dialogexpiry) setting. `0` or a negative value disables the deadline |410| `CLAUDE_CODE_USER_DIALOG_TIMEOUT_MS` | Deadline in milliseconds before Claude Code cancels a dialog it forwards to a remote client such as a [Remote Control](/docs/en/remote-control) or SDK host, or the approval dialog for a [held cross-session message](/docs/en/cross-session-messaging#control-inbound-messages); permission prompts and `AskUserQuestion` questions use their own flows and aren't governed by it. On Claude Code v2.1.236 or later, it also bounds the mid-session [Fable usage-credits consent prompt](/docs/en/model-config#fable-and-usage-credits) in a session that may be running unattended. [Control inbound messages](/docs/en/cross-session-messaging#control-inbound-messages) and [non-interactive sessions](/docs/en/cross-session-messaging#non-interactive-sessions) cover the full held-message expiry rules, including the cases where the deadline doesn't apply. Overrides the [`dialogExpiry`](/docs/en/settings-reference#dialogexpiry) setting. `0` or a negative value disables the deadline. Ignored in [project and local settings](/docs/en/settings-reference#variables-claude-code-ignores-in-env) |
409| `CLAUDE_CODE_USE_ANTHROPIC_AWS` | Use [Claude Platform on AWS](/docs/en/claude-platform-on-aws) |411| `CLAUDE_CODE_USE_ANTHROPIC_AWS` | Use [Claude Platform on AWS](/docs/en/claude-platform-on-aws) |
410| `CLAUDE_CODE_USE_BEDROCK` | Use [Amazon Bedrock](/docs/en/amazon-bedrock) |412| `CLAUDE_CODE_USE_BEDROCK` | Use [Amazon Bedrock](/docs/en/amazon-bedrock) |
411| `CLAUDE_CODE_USE_FOUNDRY` | Use [Microsoft Foundry](/docs/en/microsoft-foundry) |413| `CLAUDE_CODE_USE_FOUNDRY` | Use [Microsoft Foundry](/docs/en/microsoft-foundry) |
415| `CLAUDE_CODE_USE_VERTEX` | Use [Google Cloud's Agent Platform](/docs/en/google-vertex-ai) |417| `CLAUDE_CODE_USE_VERTEX` | Use [Google Cloud's Agent Platform](/docs/en/google-vertex-ai) |
416| `CLAUDE_CODE_WEBFETCH_CACHE_TTL_MS` | Set to the number of milliseconds [WebFetch](/docs/en/tools-reference#webfetch-tool-behavior) keeps each fetched URL's response cached. The default is `900000`, which is 15 minutes. Takes plain digits only; `0`, a decimal, or any other spelling keeps the default. Claude Code reads the value once per launch, so a change in a settings `env` block applies when you next launch `claude`. Requires Claude Code v2.1.233 or later |418| `CLAUDE_CODE_WEBFETCH_CACHE_TTL_MS` | Set to the number of milliseconds [WebFetch](/docs/en/tools-reference#webfetch-tool-behavior) keeps each fetched URL's response cached. The default is `900000`, which is 15 minutes. Takes plain digits only; `0`, a decimal, or any other spelling keeps the default. Claude Code reads the value once per launch, so a change in a settings `env` block applies when you next launch `claude`. Requires Claude Code v2.1.233 or later |
417| `CLAUDE_CODE_WEBFETCH_DEADLINE_MS` | Upper bound in milliseconds on how long [WebFetch](/docs/en/tools-reference#webfetch-tool-behavior) waits for a page to download, including any redirects it follows. A download that hasn't completed by then fails with a deadline error. The default is `300000`, which is five minutes. Set to `0` to remove the limit. Takes plain digits only; a decimal or any other spelling keeps the default. Requires Claude Code v2.1.268 or later |419| `CLAUDE_CODE_WEBFETCH_DEADLINE_MS` | Upper bound in milliseconds on how long [WebFetch](/docs/en/tools-reference#webfetch-tool-behavior) waits for a page to download, including any redirects it follows. A download that hasn't completed by then fails with a deadline error. The default is `300000`, which is five minutes. Set to `0` to remove the limit. Takes plain digits only; a decimal or any other spelling keeps the default. Requires Claude Code v2.1.268 or later |
420| `CLAUDE_CODE_WEB_SEARCH_REFILLS_PER_HOUR` | Rate at which a session's [WebSearch limit](/docs/en/tools-reference#session-search-limit) refills, in calls per hour. The default is `100` in an interactive terminal session. In a [non-interactive](/docs/en/headless) session the default is `0`, which turns refill off. Takes plain digits only; any other spelling reads as unset. Requires Claude Code v2.1.290 or later |
418| `CLAUDE_CODE_WORKER_CHECKIN_SCHEDULE` | When `CLAUDE_AUTO_BACKGROUND_TASKS` is set to `1`, how long Claude Code waits before each reminder to Claude to check on [background subagents](/docs/en/sub-agents#run-subagents-in-foreground-or-background) that are still running. Takes one or more comma-separated waits in whole seconds from `1` to `86400`, such as `600` or `600,1800,3600`. Each value is the wait before the next reminder, and the last value repeats. Takes plain digits only; any other value or spelling reads as unset. When unset, there are no reminders. Requires Claude Code v2.1.283 or later |421| `CLAUDE_CODE_WORKER_CHECKIN_SCHEDULE` | When `CLAUDE_AUTO_BACKGROUND_TASKS` is set to `1`, how long Claude Code waits before each reminder to Claude to check on [background subagents](/docs/en/sub-agents#run-subagents-in-foreground-or-background) that are still running. Takes one or more comma-separated waits in whole seconds from `1` to `86400`, such as `600` or `600,1800,3600`. Each value is the wait before the next reminder, and the last value repeats. Takes plain digits only; any other value or spelling reads as unset. When unset, there are no reminders. Requires Claude Code v2.1.283 or later |
419| `CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS` | How many agents a single [workflow](/docs/en/workflows) run executes at once, from `1` to `256`. By default, a run executes up to 16 agents at once, fewer when Claude Code has fewer CPUs available; queued `agent()` calls wait for a free slot. Each running agent's transcript stays in Claude Code's memory, so higher values raise memory use. Takes plain digits only; out-of-range values and other spellings keep the default. Requires Claude Code v2.1.269 or later |422| `CLAUDE_CODE_WORKFLOW_MAX_CONCURRENT_AGENTS` | How many agents a single [workflow](/docs/en/workflows) run executes at once, from `1` to `256`. By default, a run executes up to 16 agents at once, fewer when Claude Code has fewer CPUs available; queued `agent()` calls wait for a free slot. Each running agent's transcript stays in Claude Code's memory, so higher values raise memory use. Takes plain digits only; out-of-range values and other spellings keep the default. Requires Claude Code v2.1.269 or later |
420| `CLAUDE_CODE_WORKFLOW_PREFIX_STAGGER_MS` | Upper bound in milliseconds on how long a [workflow](/docs/en/workflows) agent waits for a same-prefix sibling's first response to begin before sending its own first request. When a fan-out starts several agents that share a [prompt-cache prefix](/docs/en/workflows#prompt-caching-in-a-fan-out), Claude Code holds all but the first agent for up to this long so the rest read the cached prefix instead of each processing it uncached. Default `5000`. Set to `0` to disable the wait. When `DISABLE_PROMPT_CACHING` is set, agents never wait. Requires Claude Code v2.1.229 or later |423| `CLAUDE_CODE_WORKFLOW_PREFIX_STAGGER_MS` | Upper bound in milliseconds on how long a [workflow](/docs/en/workflows) agent waits for a same-prefix sibling's first response to begin before sending its own first request. When a fan-out starts several agents that share a [prompt-cache prefix](/docs/en/workflows#prompt-caching-in-a-fan-out), Claude Code holds all but the first agent for up to this long so the rest read the cached prefix instead of each processing it uncached. Default `5000`. Set to `0` to disable the wait. When `DISABLE_PROMPT_CACHING` is set, agents never wait. Requires Claude Code v2.1.229 or later |
