Updates·August 4, 2026, 12:38

Claude Code moves slow tool calls to the background after two minutes

AI-generated from the sources listed, with automated source checks.

When an MCP call in Claude Code runs for more than two minutes, it is moved to a background task so Claude can keep working. The threshold can be changed, and the feature can be turned off.

If you use Claude Code with external tools connected via MCP, a slow tool call can now end up in the background instead of stopping the whole conversation. MCP is a standard that lets AI programs use external tools and services.

How it works

According to Anthropic's documentation, this applies when an MCP tool call in the main conversation is still running after two minutes. The call is then moved to a background task, and the session is not blocked.

Claude gets the task ID right away and can keep working. When the call finishes, the result arrives as a task notification. The transcript shows a line in the form "MCP task <server-task-id> (<server>/<tool>) completed."

In practice, this means a heavy search or a slow analysis no longer has to hold you back while you wait.

Controls and settings

A background task can be viewed and stopped with the /tasks command. However, the task does not survive if the session ends.

The two-minute threshold can be changed with the environment variable CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS, which is specified in milliseconds. If it is set to 0, automatic background execution is turned off. If CLAUDE_CODE_DISABLE_MCP_TASK_BACKGROUND is set to 1, Claude waits for a task's result instead.

An independent guide on Claude Code Hub describes the status line showing, for example, "1 MCP task," and says /tasks (alias /bashes) has a section for MCP tasks. There, you can select a task with the arrow keys and stop it with x.

Beta and unclear version requirements

Anthropic says MCP Tasks is in public beta in Claude Code CLI and requires version 2.1.304 or later. The guide from Claude Code Hub, by contrast, mentions version 2.1.212 for background execution of calls lasting more than two minutes. The sources do not make clear whether these are two different features, so the version requirement is unclear.

Background in the MCP standard itself

The MCP standard itself includes a so-called task principle, which makes it possible to call now and retrieve the result later. A call gets a task ID, which can be used to ask for status and results for a period after completion, set by the server itself. The proposal, SEP-1686, was delivered as an experimental feature in the specification from November 25, 2025.

The draft of the next specification moves tasks out of the core protocol and into an extension. The details may therefore change while the feature is in beta.