{"name":"ENABLE_CLAUDEAI_MCP_SERVERS","slug":"enable-claudeai-mcp-servers","family":"env","title":"Environment variables","noun":"environment variable","description":"Eval sandboxes force claude.ai MCP servers off so they can't reach real servers.","description_source":"entry","described_by":{"version":"2.1.251","anchor":"eval-sandboxes-run-with-claude-ai-mcp-servers-off"},"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":"2.1.63","released_at":"2026-02-28 02:43:42","spans":3}},"aliases":[],"entries":[{"version":"2.1.290","anchor":"claudeai-connector-list-tracking-mcp-allowlist-handles-cla","heading":"MCP allowlists now apply more strictly to claude.ai connectors","line":"An organisation's MCP allowlist now refuses claude.ai connectors it cannot find or does not admit, and matches them by their real name","released_at":"2026-10-05 18:12:44","reason":"found in this entry's text"},{"version":"2.1.251","anchor":"eval-sandboxes-run-with-claude-ai-mcp-servers-off","heading":"Eval sandboxes run with claude.ai MCP servers off","line":"Eval sandboxes force claude.ai MCP servers off so they can't reach real servers.","released_at":"2026-08-28 15:34:26","reason":"named in this entry, found in this entry's text"},{"version":"2.1.251","anchor":"cloud-routines-explain-in-more-detail-why-a-connector-is-mis","heading":"Cloud routines explain in more detail why a connector is missing","line":"When a cloud routine can't load a connector, you now see the specific reason.","released_at":"2026-08-28 15:34:26","reason":"found in this entry's text"},{"version":"2.1.63","anchor":"claude-ai-mcp-servers-enabled-by-default","heading":"claude.ai MCP Servers Enabled by Default","line":null,"released_at":"2026-02-28 02:43:42","reason":"found in this entry's text"},{"version":"2.1.14","anchor":"claude-ai-mcp-server-integration-improvements","heading":"Claude.ai MCP Server Integration Improvements","line":null,"released_at":"2026-01-20 22:37:25","reason":"found in this entry's text"}],"entries_total":5,"docs":[{"source":"claude-code","path":"agent-sdk\/claude-code-features","title":"Use Claude Code features in the SDK","documented":false},{"source":"claude-code","path":"mcp","title":"Connect Claude Code to tools via MCP","documented":false},{"source":"claude-code","path":"network-config","title":"Enterprise network configuration","documented":false}],"docs_total":3,"gates":[],"related":[{"name":"ENABLE_BETA_TRACING_DETAILED","slug":"enable-beta-tracing-detailed","description":"Detailed beta tracing now also requires that the session is not diskless, so it stops in sessions that avoid writing to disk"},{"name":"ENABLE_ENHANCED_TELEMETRY_BETA","slug":"enable-enhanced-telemetry-beta","description":"Older name for `CLAUDE_CODE_ENHANCED_TELEMETRY_BETA`, read from `process.env` only when that variable is unset. A value of `1`, `true`, `yes` or `on` turns on the enhanced OpenTelemetry tracing spans (such as the `interaction` span); `ENABLE_BETA_TRACING_DETAILED` also turns them on. A true value in a settings `env` block is listed with the note `(adds traces to the telemetry export)`."},{"name":"ENABLE_LOCKLESS_UPDATES","slug":"enable-lockless-updates","description":null},{"name":"ENABLE_LSP_TOOL","slug":"enable-lsp-tool","description":null},{"name":"ENABLE_MCP_LARGE_OUTPUT_FILES","slug":"enable-mcp-large-output-files","description":"MCP_TOOL_TIMEOUT is parsed with a minimum of 1 and ENABLE_MCP_LARGE_OUTPUT_FILES only disables when explicitly false."},{"name":"ENABLE_PID_BASED_VERSION_LOCKING","slug":"enable-pid-based-version-locking","description":null},{"name":"ENABLE_PROMPT_CACHING_1H","slug":"enable-prompt-caching-1h","description":"You can pin the prompt cache to five minutes or an hour, separately for subagents."},{"name":"ENABLE_PROMPT_CACHING_1H_BEDROCK","slug":"enable-prompt-caching-1h-bedrock","description":"When `1`, `true`, `yes` or `on` and the API provider is Bedrock, requests use a `1h` prompt cache TTL. It applies only when no earlier source decides the TTL: `FORCE_PROMPT_CACHING_5M`, the `CLAUDE_CODE_PROMPT_CACHE_TTL` or `CLAUDE_CODE_SUBAGENT_PROMPT_CACHE_TTL` env vars, the `promptCacheTtl` or `subagentPromptCacheTtl` settings, and an agent's frontmatter TTL all take precedence. `ENABLE_PROMPT_CACHING_1H` does the same for every provider."},{"name":"ENABLE_SESSION_BACKGROUNDING","slug":"enable-session-backgrounding","description":null},{"name":"ENABLE_SESSION_PERSISTENCE","slug":"enable-session-persistence","description":null}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/enable-claudeai-mcp-servers","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}