CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS is a Claude Code environment variable: Enables an on-demand MCP-tool refresh capability, grouped with CLAUDE_CODE_ENABLE_TASKS and CLAUDE_CODE_ENABLE_REMOTE_RECAP. It lets a session re-fetch an MCP server's tool list at runtime rather than only at connect — the mechanism behind the release's plugin-MCP reconnect-after-idle fix. Added between v2.1.143 and v2.1.212 and still present in v2.1.294. It is not in the official reference.

Status	Present in v2.1.294
Added	Added between v2.1.143 and v2.1.212
Category	MCP
Official docs	Not listed

How to set it

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

export CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS=<value>
claude

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

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

Release notes that mention it

claude-code-env-vars-v2-1-212

Related variables

ENABLE_CLAUDEAI_MCP_SERVERS: Enable Claude.ai-hosted MCP servers.
ENABLE_MCP_LARGE_OUTPUT_FILES: Enable large output files for MCP.
CLAUDE_CODE_REMOTE_TOOLS_ADOPT_MCP
CLAUDE_CODE_TERMINAL_MCP_TOOLS
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

What does CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS do?

Enables an on-demand MCP-tool refresh capability, grouped with CLAUDE_CODE_ENABLE_TASKS and CLAUDE_CODE_ENABLE_REMOTE_RECAP. It lets a session re-fetch an MCP server's tool list at runtime rather than only at connect — the mechanism behind the release's plugin-MCP reconnect-after-idle fix.

Which Claude Code version has CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS?

Added between v2.1.143 and v2.1.212 and still present in v2.1.294.

How do I set CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS?

Export it before starting Claude Code (export CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS=value), or add it to the "env" object in ~/.claude/settings.json to apply it to every session.

All variables, searchable: Claude Code environment variables.