CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.
What it is
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
Anthropic's own wording. Read off Environment variables, captured 2026-08-28.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.160 – 2.1.243 75 releases | in the build | bool | — |
| 2.1.138 – 2.1.159 20 releases | in the build | — | — |
A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.
Changelog entries naming it
No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.138 without anybody writing a line about it.
Documentation pages
- Environment variables reference table Claude Code CLI
- Claude Code changelog mentions it Claude Code CLI
- Fullscreen rendering mentions it Claude Code CLI
- Claude Code settings reference mentions it Claude Code CLI
A reference table page is one whose own table defines this name, and it is where the description above came from. A page that mentions it carries the name somewhere in its text and may say nothing about it at all. Every page carrying it.
Names beside it
Every environment variable in the inventory starting claude_code_disable, up to twelve of them.
CLAUDE_CODE_DISABLE_1M_CONTEXTSet 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](/docs/en/model-config#sonnet-5-context-window) and Fable 5, 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) 2.1.138
CLAUDE_CODE_DISABLE_ADAPTIVE_THINKINGSet 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 5, Sonnet 5, or Opus 4.7 and later, which always use adaptive reasoning 2.1.138
CLAUDE_CODE_DISABLE_ADMIN_ENV_UNIONSet 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 2.1.223
CLAUDE_CODE_DISABLE_ADVISOR_TOOLSet 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 2.1.138
CLAUDE_CODE_DISABLE_AGENT_VIEWSet 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 2.1.139
CLAUDE_CODE_DISABLE_AGENTS_FLEETNo description from anybody. 2.1.138
CLAUDE_CODE_DISABLE_ARTIFACTSet 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 2.1.172
CLAUDE_CODE_DISABLE_ATTACHMENTSSet to 1 to disable attachment processing. File mentions with @ syntax are sent as plain text instead of being expanded into file content 2.1.138
CLAUDE_CODE_DISABLE_AUTO_MEMORYSet 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 2.1.138
CLAUDE_CODE_DISABLE_BACKGROUND_TASKSSet 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 2.1.138
CLAUDE_CODE_DISABLE_BEDROCK_CONTENT_TYPE_DEFAULTSet to 1 to stop Claude Code from treating an [Amazon Bedrock](/docs/en/amazon-bedrock) streaming response with a missing or empty Content-Type header as the binary application/vnd.amazon.eventstream format. Amazon Bedrock always sends that header, so when it's absent, a [proxy stripped it](/docs/en/amazon-bedrock#streaming-errors-behind-a-gateway-or-proxy) and by default Claude Code decodes the body as the binary format anyway. Set this variable only when the proxy strips the header and also re-emits the body as server-sent events; Claude Code then reads the body as server-sent events instead. Requires Claude Code v2.1.239 or later 2.1.239
CLAUDE_CODE_DISABLE_BEDROCK_CONTENT_TYPE_GUARDSet to 1 to skip the check that an [Amazon Bedrock](/docs/en/amazon-bedrock) streaming response carries the application/vnd.amazon.eventstream content-type. Without this variable, a response with a different content-type fails with an error naming that content-type, which means a [gateway or proxy is transforming the response](/docs/en/amazon-bedrock#streaming-errors-behind-a-gateway-or-proxy). Set it only when the gateway rewrites the Content-Type header but passes the binary event-stream body through unmodified; if the body itself was transformed, requests fail with Truncated event message received instead. Requires Claude Code v2.1.208 or later 2.1.208
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the environment variable does. All environment variables.