CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP

Updated October 31, 2026 by Alex Sorokoletov

CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP is a Claude Code environment variable: Forces the official MCP server registry to be fetched at startup instead of deferring the fetch until the server URL lookup completes. Added in v2.1.311 and still present in v2.1.315. It is not in the official reference.

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_MCP_REGISTRY_FETCH_AT_STARTUP": "<value>"
  }
}

Related variables

• CLAUDE_CODE_MCP_STARTUP_WAIT_MS
• CLAUDE_CODE_ARTIFACT_MCP: Enables MCP runtime-capability support for artifacts; on by default.
• CLAUDE_CODE_CHROME_LATE_MCP_SERVER: When true, loads the alternate late Claude-in-Chrome MCP server module and skips installing the Chrome native host early.
• CLAUDE_CODE_CHROME_MCP_ORG_DENIED: When set, forces Claude-in-Chrome to be treated as denied by organization policy, with the cause reported as parent_org_policy.
• CLAUDE_CODE_DISABLE_MCP_TASK_BACKGROUND: Turns off automatic backgrounding of MCP tool tasks.
• CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS: Enables an on-demand MCP-tool refresh capability, grouped with CLAUDE_CODE_ENABLE_TASKS and CLAUDE_CODE_ENABLE_REMOTE_RECAP.
• CLAUDE_CODE_HOST_GUARDS_ARTIFACTS_MCP: On a desktop host, the artifacts MCP entry is skipped unless this is set to true, which keeps that entry enabled.
• CLAUDE_CODE_MAX_MCP_DESCRIPTION_LENGTH

Frequently asked questions

All variables, searchable: Claude Code environment variables.