{"name":"CLAUDE_CODE_MCP_CONNECTOR_PREWAIT_MS","slug":"claude-code-mcp-connector-prewait-ms","family":"env","title":"Environment variables","noun":"environment variable","description":"New CLAUDE_CODE_MCP_CONNECTOR_PREWAIT_MS environment variable overrides how long Claude Code waits for remote MCP servers to start","description_source":"entry","described_by":{"version":"2.1.271","anchor":"mcp-connector-prewait-now-overridable-via-claude-code-mcp-c"},"presence":{"first_seen":"2.1.271","removed_in":null,"in_current_build":true,"newest_mined":"2.1.319","builds":45,"mined_builds":159,"first_cited":{"version":"2.1.271","released_at":"2026-09-14 19:45:19","spans":1}},"aliases":[],"entries":[{"version":"2.1.286","anchor":"new-mcp-pre-wait-env-vars-for-named-servers","heading":"Two environment variables for waiting on named MCP servers at startup","line":"`CLAUDE_CODE_MCP_PREWAIT_SERVERS` and `CLAUDE_CODE_MCP_PREWAIT_SERVERS_MS` appear to let startup wait for particular MCP servers","released_at":"2026-09-30 17:14:38","reason":"found in this entry's text, named in this entry"},{"version":"2.1.284","anchor":"headless-first-turn-mcp-wait-now-holds-for-required-server","heading":"Non-interactive runs wait for required MCP servers before the first turn","line":"In `-p` and SDK sessions, Claude Code now waits for MCP servers it deems required before the first turn, even when loading is deferred","released_at":"2026-09-28 17:11:59","reason":"found in this entry's text"},{"version":"2.1.271","anchor":"mcp-connector-prewait-now-overridable-via-claude-code-mcp-c","heading":"MCP connector prewait now overridable via CLAUDE_CODE_MCP_CONNECTOR_PREWAIT_MS","line":"New CLAUDE_CODE_MCP_CONNECTOR_PREWAIT_MS environment variable overrides how long Claude Code waits for remote MCP servers to start","released_at":"2026-09-14 19:45:19","reason":"found in this entry's text, named in this entry"}],"entries_total":3,"docs":[],"docs_total":0,"gates":[],"related":[{"name":"CLAUDE_CODE_MCP_ALLOWLIST_ENV","slug":"claude-code-mcp-allowlist-env","description":"Set to `1` to spawn stdio MCP servers with only a safe baseline environment plus the server's configured `env`, instead of inheriting your shell environment"},{"name":"CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT","slug":"claude-code-mcp-always-load-join-before-input","description":"A new environment variable, `CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT`, affects always-load MCP servers when set to exactly `true`"},{"name":"CLAUDE_CODE_MCP_APPS_HOST","slug":"claude-code-mcp-apps-host","description":"With CLAUDE_CODE_MCP_APPS_HOST set to true, Claude Code tells MCP servers it accepts MCP App content"},{"name":"CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS","slug":"claude-code-mcp-auto-background-ms","description":"Elapsed time in milliseconds before a still-running MCP tool call [moves to a background task](\/docs\/en\/mcp#automatic-backgrounding-of-long-tool-calls) (default: 120000, or 2 minutes). Set to `0` to turn automatic backgrounding off. Requires Claude Code v2.1.212 or later"},{"name":"CLAUDE_CODE_MCP_HANDED_LISTINGS","slug":"claude-code-mcp-handed-listings","description":"MCP tool lists handed over by the host are now compared with the live server, and CLAUDE_CODE_MCP_HANDED_LISTINGS=0 turns them off"},{"name":"CLAUDE_CODE_MCP_MEMORY_CGROUP","slug":"claude-code-mcp-memory-cgroup","description":"On Linux you can force MCP servers into their own memory cgroup with an environment variable."},{"name":"CLAUDE_CODE_MCP_NO_REDIAL_AFTER_POLICY_REFUSAL","slug":"claude-code-mcp-no-redial-after-policy-refusal","description":"With `CLAUDE_CODE_MCP_NO_REDIAL_AFTER_POLICY_REFUSAL` set, Claude Code can stop redialing MCP servers that the sandbox network policy refused"},{"name":"CLAUDE_CODE_MCP_PREWAIT_SERVERS","slug":"claude-code-mcp-prewait-servers","description":"`CLAUDE_CODE_MCP_PREWAIT_SERVERS` and `CLAUDE_CODE_MCP_PREWAIT_SERVERS_MS` name MCP servers for remote worker sessions to wait for before the first turn"},{"name":"CLAUDE_CODE_MCP_PREWAIT_SERVERS_MS","slug":"claude-code-mcp-prewait-servers-ms","description":"`CLAUDE_CODE_MCP_PREWAIT_SERVERS` and `CLAUDE_CODE_MCP_PREWAIT_SERVERS_MS` name MCP servers for remote worker sessions to wait for before the first turn"},{"name":"CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP","slug":"claude-code-mcp-registry-fetch-at-startup","description":"Claude Code now waits to download the official MCP registry list until it's needed, unless `CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP` is set"}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/claude-code-mcp-connector-prewait-ms","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}