MCP_SERVER_CONNECTION_BATCH_SIZE

Updated October 13, 2026 by Alex Sorokoletov

MCP_SERVER_CONNECTION_BATCH_SIZE is a Claude Code environment variable: Concurrent MCP server connections. Its release history is not tracked here. It is listed in the official reference.

Status	Present in v2.1.294
Category	Network and proxy
Official docs	Listed

How to set it

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

export MCP_SERVER_CONNECTION_BATCH_SIZE=<value>
claude

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

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

Related variables

MCP_REMOTE_SERVER_CONNECTION_BATCH_SIZE: Remote MCP connection batch size.
CLAUDE_CODE_MCP_SERVER_URL: The companion to MCP_SERVER_NAME, providing the server endpoint URL.
MCP_CONNECTION_NONBLOCKING: Make MCP connections non-blocking.
CLAUDE_CODE_DISABLE_MTLS_RELOAD_ON_STALE_CONNECTION
CLAUDE_CODE_MCP_TOOL_IDLE_TIMEOUT
MCP_CONNECT_TIMEOUT_MS
MCP_TIMEOUT: MCP server connection timeout.
MCP_TOOL_TIMEOUT: Individual MCP tool execution timeout.

Frequently asked questions

What does MCP_SERVER_CONNECTION_BATCH_SIZE do?

Concurrent MCP server connections

Which Claude Code version has MCP_SERVER_CONNECTION_BATCH_SIZE?

Its release history is not tracked here.

How do I set MCP_SERVER_CONNECTION_BATCH_SIZE?

Export it before starting Claude Code (export MCP_SERVER_CONNECTION_BATCH_SIZE=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.