CLAUDE_CODE_MCP_SERVER_NAME

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_MCP_SERVER_NAME is a Claude Code environment variable: Added in v2.1.85 to identify which MCP server a helper process was acting on behalf of. Removed after just two versions. Added in v2.1.85 and still present in v2.1.294. 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_SERVER_NAME=<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_SERVER_NAME": "<value>"
  }
}

Release notes that mention it

• Claude Code v2.1.87 — 2 New Environment Variables: OAuth Console and Trusted Devices
• Claude Code v2.1.85 — 6 New Environment Variables: MCP Server Config and a 7 MB Diet
• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models

Related variables

• CLAUDE_IN_CHROME_MCP_SERVER_NAME
• 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.
• CLAUDE_CODE_MCP_STARTUP_WAIT_MS
• ENABLE_CLAUDEAI_MCP_SERVERS: Enable Claude.ai-hosted MCP servers.

Frequently asked questions

All variables, searchable: Claude Code environment variables.