CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT

Updated October 23, 2026 by Alex Sorokoletov

CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT is a Claude Code environment variable. Added in v2.1.299 and still present in v2.1.310. It is not in the official reference.

Status	Present in v2.1.310
Added	Added in v2.1.299
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_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT=<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_ALWAYS_LOAD_JOIN_BEFORE_INPUT": "<value>"
  }
}

Related variables

CLAUDE_CODE_DISABLE_MCP_TASK_BACKGROUND
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_SERVE_WORKSPACE_ROOT: Used by claude mcp serve --transport http.
CLAUDE_CODE_MCP_SERVER_NAME: Added in v2.1.85 to identify which MCP server a helper process was acting on behalf of.

Frequently asked questions

Which Claude Code version has CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT?

Added in v2.1.299 and still present in v2.1.310.

How do I set CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT?

Export it before starting Claude Code (export CLAUDE_CODE_MCP_ALWAYS_LOAD_JOIN_BEFORE_INPUT=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.