How to stop Claude Code MCP tasks in /tasks and make Claude wait for their results

Since v2.1.304, Claude Code supports MCP tasks in public beta: an MCP server runs a long job, such as a report export or a build, on its own. The tool call returns once the server accepts the job and Claude moves on. Meanwhile the footer shows a count such as 1 MCP task, and when the job ends a line like this appears in the transcript.

MCP task <server task id> (<server>/<tool>) completed.

The result goes to Claude rather than the transcript, so ask Claude for it. If Claude is idle when it arrives, Claude picks it up on its own.

1. Stop a task. Select it in /tasks and press x, or ask Claude to stop it. Esc doesn't stop it. If the server disconnected, reconnect it from /mcp first, or no cancel request reaches the server. The server may still have done some of the work.

2. Make Claude wait. Add this to the env block of settings.json and Claude waits for every MCP tool call to end.

{
  "env": {
    "CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS": "0"
  }
}

To wait only for task results, set CLAUDE_CODE_DISABLE_MCP_TASK_BACKGROUND to "1" instead. Calls running past two minutes still move to a plain background call, which doesn't survive exiting the session. Setting CLAUDE_CODE_DISABLE_BACKGROUND_TASKS to 1 alone doesn't make Claude wait for MCP tasks.

1. Get the result later. A task on a remote server keeps running after you exit. Resume the session that started it with claude --resume, and Claude Code follows the task again and gets the result if it finished meanwhile. A new session or one opened with --fork-session doesn't follow it. A stdio server's process stops when Claude Code exits, so let its tasks finish or stop them in /tasks first.

MCP tasks only appear in terminal CLI, Agent SDK and GitHub Actions sessions. The VS Code extension, the desktop app, third-party providers such as Amazon Bedrock, calls from subagents and one-shot claude -p runs don't get them. The server must support tasks and connect on protocol revision 2026-07-28.