{"name":"CLAUDE_PROJECT_UUID","slug":"claude-project-uuid","family":"env","title":"Environment variables","noun":"environment variable","description":"About 220 environment variables now parse and validate in one place, including bounds checks.","description_source":"entry","described_by":{"version":"2.1.228","anchor":"about-220-more-environment-variables-move-to-the-typed-regis"},"presence":{"first_seen":"2.1.174","removed_in":null,"in_current_build":true,"newest_mined":"2.1.309","builds":118,"mined_builds":150,"first_cited":null},"aliases":[],"entries":[{"version":"2.1.299","anchor":"project-context-block-gate-tengu-quill-marten","heading":"Groundwork for automatic project context in claude.ai Project sessions","line":"Claude Code can fetch context for a claude.ai Project into the session, behind a switch that is off unless turned on remotely","released_at":"2026-10-14 00:23:19","reason":"found in this entry's text, named in this entry"},{"version":"2.1.228","anchor":"about-220-more-environment-variables-move-to-the-typed-regis","heading":"About 220 more environment variables move to the typed registry","line":"About 220 environment variables now parse and validate in one place, including bounds checks.","released_at":"2026-08-11 17:45:45","reason":"named in this entry, found in this entry's text"},{"version":"2.1.174","anchor":"projects-tool-read-and-write-claude-ai-project-docs","heading":"Projects Tool \u2014 Read and Write claude.ai Project Docs","line":null,"released_at":"2026-06-11 22:27:52","reason":"found in this entry's text"}],"entries_total":3,"docs":[],"docs_total":0,"gates":[],"related":[{"name":"CLAUDE_PROJECT_TOOL","slug":"claude-project-tool","description":"When true (`1`, `true`, `yes` or `on`), Claude Code loads the `Projects` tool (search hint `read and write the session's attached claude.ai project`), which enables itself only when the `allow_projects_tool` policy permits it and `CLAUDE_PROJECT_UUID` is set, and fetches a context block for that claude.ai project into the session's user context as `attachedProject`. The fetch is skipped when the policy disallows it, the API provider is not supported, or Claude Code runs in essential-traffic-only mode. Unset, neither the tool nor the project context is loaded."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/claude-project-uuid","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}