{"name":"ANTHROPIC_BASE_URL","slug":"anthropic-base-url","family":"env","title":"Environment variables","noun":"environment variable","description":"Override the API endpoint to route requests through a proxy or gateway. When set to a non-first-party host, [MCP tool search](\/docs\/en\/mcp#scale-with-mcp-tool-search) is disabled by default. Set `ENABLE_TOOL_SEARCH=true` if your proxy forwards `tool_reference` blocks. As of v2.1.196, [Remote Control](\/docs\/en\/remote-control#requirements) is disabled when this points at a host other than `api.anthropic.com`, matching its behavior on Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry","description_source":"docs","described_by":{"doc":"claude-code\/env-vars","title":"Environment variables"},"presence":{"first_seen":"2.1.138","removed_in":null,"in_current_build":true,"newest_mined":"2.1.308","builds":149,"mined_builds":149,"first_cited":{"version":"2.1.70","released_at":"2026-03-06 00:09:06","spans":7}},"aliases":[],"entries":[{"version":"2.1.307","anchor":"auth-token-forwarding-to-custom-anthropic-base-url-simplifie","heading":"Fewer conditions before ANTHROPIC_AUTH_TOKEN is sent to a custom address","line":"Claude Code dropped one check that could stop `ANTHROPIC_AUTH_TOKEN` from being sent to a matching `ANTHROPIC_BASE_URL`","released_at":"2026-10-21 20:47:18","reason":"named in this entry, found in this entry's text"},{"version":"2.1.305","anchor":"plugin-eval-can-pass-the-session-api-key-to-its-test-runs-by","heading":"claude plugin eval passes your session's API key to its test runs","line":"With an API key session, `claude plugin eval` now hands the key to its test runs itself, except on Windows, where you must set `ANTHROPIC_API_KEY`","released_at":"2026-10-20 19:29:36","reason":"found in this entry's text"},{"version":"2.1.304","anchor":"tool-search-refusal-by-a-custom-anthropic-base-url-endpoint","heading":"Tool search is tried through custom API endpoints and paused for a day if refused","line":"With a custom `ANTHROPIC_BASE_URL`, Claude Code now tries MCP tool search and turns it off for a day only if that endpoint refuses it","released_at":"2026-10-19 19:47:15","reason":"found in this entry's text, named in this entry"},{"version":"2.1.302","anchor":"claude-bg-gateway-withheld-scrubbed-from-the-env","heading":"Background sessions no longer pass on the withheld-gateway marker","line":"`CLAUDE_BG_GATEWAY_WITHHELD` is now removed along with other background-session variables, so it does not carry into sessions started from there","released_at":"2026-10-16 16:48:28","reason":"found in this entry's text"},{"version":"2.1.302","anchor":"new-no-llm-gateway-error-for-background-sessions-opened-fr","heading":"Clear gateway message for background sessions opened from another folder","line":"A background session opened from another folder without its LLM gateway now says so, instead of asking you to log in","released_at":"2026-10-16 16:48:28","reason":"found in this entry's text, named in this entry"},{"version":"2.1.302","anchor":"background-sessions-anthropic-base-url-not-forwarded-to-oth","heading":"Background sessions in another folder no longer inherit your API base URL","line":"A background session started in a different folder no longer receives `ANTHROPIC_BASE_URL`, and `CLAUDE_CODE_AUTO_MODE_MODEL` is now passed on","released_at":"2026-10-16 16:48:28","reason":"found in this entry's text"},{"version":"2.1.299","anchor":"remote-settings-fetch-refuses-to-send-api-key-to-non-anthrop","heading":"Your API key is no longer sent to non-Anthropic hosts when fetching remote settings","line":"If `ANTHROPIC_BASE_URL` points somewhere other than Anthropic, Claude Code no longer sends your API key when fetching remote settings","released_at":"2026-10-14 00:23:19","reason":"found in this entry's text, named in this entry"},{"version":"2.1.299","anchor":"stuck-permissionanswer-and-api-key-hardening","heading":"API key withheld when ANTHROPIC_BASE_URL is not an Anthropic host","line":"On one request path, Claude Code no longer sends your API key to an `ANTHROPIC_BASE_URL` that is not an Anthropic host","released_at":"2026-10-14 00:23:19","reason":"found in this entry's text, named in this entry"},{"version":"2.1.296","anchor":"managed-settings-env-now-injects-a-computed-anthropic-base-u","heading":"Managed settings with allowedProviders can now set ANTHROPIC_BASE_URL automatically","line":"When managed settings use `allowedProviders`, Claude Code may set `ANTHROPIC_BASE_URL` itself unless the managed settings already set it","released_at":"2026-10-09 16:58:10","reason":"found in this entry's text, named in this entry"},{"version":"2.1.295","anchor":"telemetry-base-url-now-from-a-helper-printistty-omitted-i","heading":"Diskless sessions turn off raw API body logging","line":"In a diskless session, `OTEL_LOG_RAW_API_BODIES` is ignored and some terminal details are left out of usage data","released_at":"2026-10-08 18:22:58","reason":"found in this entry's text"}],"entries_total":42,"docs":[{"source":"claude-code","path":"env-vars","title":"Environment variables","documented":true},{"source":"api","path":"cli-sdks-libraries\/cli\/authentication","title":"On a remote host without a browser:","documented":false},{"source":"api","path":"cli-sdks-libraries\/sdks\/csharp","title":"csharp","documented":false},{"source":"api","path":"cli-sdks-libraries\/sdks\/java","title":"java","documented":false},{"source":"api","path":"cli-sdks-libraries\/sdks\/python","title":"For Amazon Bedrock support","documented":false},{"source":"api","path":"manage-claude\/cmek","title":"cmek","documented":false},{"source":"api","path":"managed-agents\/self-hosted-sandboxes","title":"spawn.sh: called once per claimed work item","documented":false},{"source":"api","path":"managed-agents\/self-hosted-sandboxes-reference","title":"self-hosted-sandboxes-reference","documented":false},{"source":"api","path":"managed-agents\/self-hosted-sandboxes-workers","title":"self-hosted-sandboxes-workers","documented":false},{"source":"claude-code","path":"advisor","title":"Escalate hard decisions with the advisor tool","documented":false}],"docs_total":13,"gates":[],"related":[{"name":"ANTHROPIC_API_KEY","slug":"anthropic-api-key","description":"API key sent as `X-Api-Key` header. When set, this key is used instead of your Claude Pro, Max, Team, or Enterprise subscription even if you are logged in. In non-interactive mode (`-p`), the key is always used when present. In interactive mode, you are prompted to approve the key once before it overrides your subscription. To use your subscription instead, run `unset ANTHROPIC_API_KEY`"},{"name":"ANTHROPIC_AUTH_TOKEN","slug":"anthropic-auth-token","description":"Custom value for the `Authorization` header (the value you set here will be prefixed with `Bearer `)"},{"name":"ANTHROPIC_AWS_API_KEY","slug":"anthropic-aws-api-key","description":"Workspace API key for [Claude Platform on AWS](\/docs\/en\/claude-platform-on-aws), generated in the AWS Console. Sent as `x-api-key` and takes precedence over AWS SigV4"},{"name":"ANTHROPIC_AWS_BASE_URL","slug":"anthropic-aws-base-url","description":"Override the [Claude Platform on AWS](\/docs\/en\/claude-platform-on-aws) endpoint URL. Use for custom regions or when routing through an [LLM gateway](\/docs\/en\/llm-gateway). Defaults to `https:\/\/aws-external-anthropic.{region}.api.aws`. Claude Code resolves the region with the [same precedence as on Amazon Bedrock](\/docs\/en\/amazon-bedrock#3-configure-claude-code)"},{"name":"ANTHROPIC_AWS_WORKSPACE_ID","slug":"anthropic-aws-workspace-id","description":"Required for [Claude Platform on AWS](\/docs\/en\/claude-platform-on-aws). Sent on every request as the `anthropic-workspace-id` header"},{"name":"ANTHROPIC_BEDROCK_BASE_URL","slug":"anthropic-bedrock-base-url","description":"Override the Amazon Bedrock endpoint URL. Use for custom Amazon Bedrock endpoints or when routing through an [LLM gateway](\/docs\/en\/llm-gateway). See [Amazon Bedrock](\/docs\/en\/amazon-bedrock)"},{"name":"ANTHROPIC_BEDROCK_MANTLE_BASE_URL","slug":"anthropic-bedrock-mantle-base-url","description":"Override the Amazon Bedrock Mantle endpoint URL. See [Mantle endpoint](\/docs\/en\/amazon-bedrock#use-the-mantle-endpoint)"},{"name":"ANTHROPIC_BEDROCK_REGION_PREFIX","slug":"anthropic-bedrock-region-prefix","description":"Cross-region inference profile prefix (`us`, `eu`, `apac`, `jp`, `au`, or `global`) Claude Code tries first instead of the one derived from the AWS region. Ignored in AWS GovCloud regions. Requires Claude Code v2.1.224 or later. See [Amazon Bedrock](\/docs\/en\/amazon-bedrock#cross-region-inference-profile-prefixes)"},{"name":"ANTHROPIC_BEDROCK_SERVICE_TIER","slug":"anthropic-bedrock-service-tier","description":"Amazon Bedrock [service tier](https:\/\/docs.aws.amazon.com\/bedrock\/latest\/userguide\/service-tiers-inference.html) (`default`, `flex`, or `priority`). Sent as the `X-Amzn-Bedrock-Service-Tier` header. See [Amazon Bedrock](\/docs\/en\/amazon-bedrock#service-tiers)"},{"name":"ANTHROPIC_BETAS","slug":"anthropic-betas","description":"Comma-separated list of additional `anthropic-beta` header values to include in API requests. Claude Code already sends the beta headers it needs; use this to opt into an [Anthropic API beta](https:\/\/platform.claude.com\/docs\/en\/api\/beta-headers) before Claude Code adds native support. Unlike the [`--betas` flag](\/docs\/en\/cli-reference#cli-flags), which requires API key authentication, this variable works with all auth methods including Claude.ai subscription"}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/anthropic-base-url","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}