CLAUDE_CODE_MCP_SERVE_WORKSPACE_ROOT

Updated October 18, 2026 by Alex Sorokoletov

CLAUDE_CODE_MCP_SERVE_WORKSPACE_ROOT is a Claude Code environment variable: Used by claude mcp serve --transport http. Registers a workspace-root folder for the server; only a folder beneath the server's own is accepted, and a path outside it is ignored with a warning. First appears in v2.1.302, absent from that release's changelog. Added between v2.1.301 and v2.1.303 and still present in v2.1.303. 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_SERVE_WORKSPACE_ROOT=<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_SERVE_WORKSPACE_ROOT": "<value>"
  }
}

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-303

Related variables

• CLAUDE_CODE_MCP_SERVE_INTERFACE_MIN_VERSION
• CLAUDE_CODE_MCP_SERVE_SETTINGS
• CLAUDE_CODE_MCP_SERVE_TOOL_OUTPUT
• 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_MAX_MCP_DESCRIPTION_LENGTH
• CLAUDE_CODE_MCP_ALLOWLIST_ENV: Specifies an allowlist of environment variables that MCP servers can access.
• CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS
• CLAUDE_CODE_MCP_INSTR_DELTA: Delta/incremental MCP instruction updates.

Frequently asked questions

All variables, searchable: Claude Code environment variables.