Environment Variables

Environment variables that control Claude Code behavior

Claude Code reads a number of environment variables at startup and throughout a session. These complement settings.json for cases where you need machine- or process-level control without modifying files.

ANTHROPIC_API_KEY is required when authenticating via API key. Without it (and without an active OAuth session), Claude Code cannot make API calls.

Authentication

Variable	Default	Description
ANTHROPIC_API_KEY	—	Anthropic API key used for direct authentication
ANTHROPIC_BASE_URL	—	Override the Anthropic API base URL
ANTHROPIC_UNIX_SOCKET	—	Connect to the Anthropic API over a Unix domain socket
CLAUDE_CODE_OAUTH_TOKEN	—	OAuth bearer token injected by the calling environment
AWS_BEARER_TOKEN_BEDROCK	—	Bearer token for AWS Bedrock authentication

Cloud provider routing

Variable	Default	Description
CLAUDE_CODE_USE_BEDROCK	—	Route requests through AWS Bedrock
CLAUDE_CODE_USE_VERTEX	—	Route requests through Google Cloud Vertex AI
CLAUDE_CODE_USE_FOUNDRY	—	Route requests through Microsoft Azure AI Foundry
AWS_REGION	us-east-1	AWS region for Bedrock requests
AWS_DEFAULT_REGION	us-east-1	Fallback AWS region when AWS_REGION is not set
ANTHROPIC_BEDROCK_BASE_URL	—	Override the Bedrock endpoint base URL
CLOUD_ML_REGION	us-east5	Default Vertex AI region
CLAUDE_CODE_SKIP_BEDROCK_AUTH	—	Skip Bedrock authentication checks

Vertex AI per-model region overrides

Each variable below pins a specific model to a Vertex AI region:

Variable	Model prefix
VERTEX_REGION_CLAUDE_HAIKU_4_5	claude-haiku-4-5
VERTEX_REGION_CLAUDE_3_5_HAIKU	claude-3-5-haiku
VERTEX_REGION_CLAUDE_3_5_SONNET	claude-3-5-sonnet
VERTEX_REGION_CLAUDE_3_7_SONNET	claude-3-7-sonnet
VERTEX_REGION_CLAUDE_4_0_SONNET	claude-sonnet-4
VERTEX_REGION_CLAUDE_4_5_SONNET	claude-sonnet-4-5
VERTEX_REGION_CLAUDE_4_6_SONNET	claude-sonnet-4-6
VERTEX_REGION_CLAUDE_4_0_OPUS	claude-opus-4
VERTEX_REGION_CLAUDE_4_1_OPUS	claude-opus-4-1

Configuration paths

Variable	Default	Description
CLAUDE_CONFIG_DIR	~/.claude	Override the Claude configuration home directory

Operational modes

Variable	Default	Description
CLAUDE_CODE_SIMPLE	—	Enable bare/simple mode: skips hooks, LSP, plugin sync, skill directory walk, attribution, background prefetches, and all keychain reads. Auth is strictly ANTHROPIC_API_KEY or apiKeyHelper. Equivalent to the --bare CLI flag
CLAUDE_CODE_REMOTE	—	Enable remote container mode; sets max-old-space-size=8192 and enables all hook events
CLAUDE_CODE_REMOTE_SESSION_ID	—	Session ID for the current remote session
CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC	—	Disable non-essential network traffic (analytics, telemetry, etc.)
CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS	—	Disable experimental beta API features

Memory

Variable	Default	Description
CLAUDE_CODE_DISABLE_AUTO_MEMORY	—	Disable the auto-memory system entirely. Set to 1 or true to turn off; 0 or false to force-enable even when autoMemoryEnabled: false is in settings
CLAUDE_CODE_REMOTE_MEMORY_DIR	—	Override the base directory for remote session memory storage
CLAUDE_COWORK_MEMORY_PATH_OVERRIDE	—	Full-path override for the auto-memory directory (used by Cowork/SDK)
CLAUDE_COWORK_MEMORY_EXTRA_GUIDELINES	—	Extra memory policy text injected into memory prompts

Context and compaction

Variable	Default	Description
DISABLE_COMPACT	—	Disable context compaction entirely
DISABLE_AUTO_COMPACT	—	Disable automatic context compaction (manual compact still works)
DISABLE_BACKGROUND_TASKS	—	Disable background task execution
API_MAX_INPUT_TOKENS	—	Override the maximum input token limit
API_TARGET_INPUT_TOKENS	—	Override the target input token count for compaction

Thinking and model behavior

Variable	Default	Description
CLAUDE_CODE_DISABLE_THINKING	—	Disable extended thinking mode
DISABLE_INTERLEAVED_THINKING	—	Disable interleaved thinking

Telemetry and observability

Variable	Default	Description
OTEL_LOG_TOOL_DETAILS	—	Set to 1 to enable full tool input capture in OpenTelemetry telemetry
OTEL_EXPORTER_OTLP_PROTOCOL	—	OpenTelemetry exporter protocol (e.g. grpc, http/protobuf)
NODE_EXTRA_CA_CERTS	—	Path to extra CA certificate file for custom TLS trust roots

Shell and editor behavior

Variable	Default	Description
CLAUDE_BASH_MAINTAIN_PROJECT_WORKING_DIR	—	Reset the working directory to the project root after each Bash command
CLAUDE_CODE_GIT_BASH_PATH	—	Path to git-bash executable (Windows)
EDITOR	—	Editor to open when /memory is invoked and no $VISUAL is set
VISUAL	—	Preferred editor; takes precedence over $EDITOR
SHELL	—	Shell used for command execution

Networking

Variable	Default	Description
CLAUDE_CODE_DISABLE_COMMAND_INJECTION_CHECK	—	Disable the command injection safety check (not recommended)

How environment variables interact with settings

Environment variables are evaluated at the process level and take effect for the lifetime of the Claude Code process. They are not written to settings.json.

The env field in settings.json lets you set environment variables that are applied to each Claude Code session:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://my-proxy.example.com",
    "NODE_EXTRA_CA_CERTS": "/etc/ssl/my-ca-bundle.crt"
  }
}

Truthy values for boolean environment variables are 1, true, yes, and on (case-insensitive). Falsy values are 0, false, no, and off. An unset variable is treated as falsy.