{"name":"CLAUDE_PROJECT_TOOL","slug":"claude-project-tool","family":"env","title":"Environment variables","noun":"environment variable","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.","description_source":"code","described_by":{"bundle":"2.1.185","author":"claude-opus-5-5"},"presence":{"first_seen":"2.1.174","removed_in":"2.1.186","in_current_build":false,"newest_mined":"2.1.308","builds":10,"mined_builds":149,"first_cited":null},"aliases":[],"entries":[],"entries_total":0,"docs":[],"docs_total":0,"gates":[],"related":[{"name":"CLAUDE_PROJECT_UUID","slug":"claude-project-uuid","description":"About 220 environment variables now parse and validate in one place, including bounds checks."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/claude-project-tool","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}