CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS is a Claude Code environment variable: Default 600,000ms (10 minutes). Directly backs v2.1.113's "subagents that stall mid-stream now fail with a clear error after 10 minutes" changelog bullet. Tune up for long-running research, down for tight CI. Added between v2.1.108 and v2.1.114 and still present in v2.1.294. It is listed in the official reference.

Status	Present in v2.1.294
Added	Added between v2.1.108 and v2.1.114
Category	Network and proxy
Official docs	Listed

How to set it

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

export CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS=<value>
claude

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

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

Release notes that mention it

Related variables

CLAUDE_CODE_STALL_TIMEOUT_MS_FOR_TESTING
API_FORCE_IDLE_TIMEOUT
API_TIMEOUT_MS: Request timeout in milliseconds.
BASH_DEFAULT_TIMEOUT_MS
BASH_MAX_TIMEOUT_MS
CLAUDE_AFK_TIMEOUT_MS
CLAUDE_BYTE_STREAM_IDLE_TIMEOUT_MS
CLAUDE_CODE_CONNECT_TIMEOUT_MS

Frequently asked questions

What does CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS do?

Default 600,000ms (10 minutes). Directly backs v2.1.113's "subagents that stall mid-stream now fail with a clear error after 10 minutes" changelog bullet. Tune up for long-running research, down for tight CI.

Which Claude Code version has CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS?

Added between v2.1.108 and v2.1.114 and still present in v2.1.294.

How do I set CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS?

Export it before starting Claude Code (export CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS=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.