CLAUDE_CODE_SESSIONEND_HOOKS_TIMEOUT_MS

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_SESSIONEND_HOOKS_TIMEOUT_MS is a Claude Code environment variable: Set the timeout in milliseconds for hooks that run when a Claude Code session ends. Session-end hooks (like SessionEnd in the hooks config) run cleanup scripts on exit — this variable controls how long Claude Code waits for those hooks to complete before force-exiting. Added between v2.1.77 and v2.1.79 and still present in v2.1.294. It is listed in the official reference.

How to set it

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

export CLAUDE_CODE_SESSIONEND_HOOKS_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_CODE_SESSIONEND_HOOKS_TIMEOUT_MS": "<value>"
  }
}

Release notes that mention it

• Claude Code v2.1.74 — 2 New Environment Variables: Frame Timing & Session End Hooks

Related variables

• API_FORCE_IDLE_TIMEOUT
• API_TIMEOUT_MS: Request timeout in milliseconds.
• BASH_DEFAULT_TIMEOUT_MS
• BASH_MAX_TIMEOUT_MS
• CLAUDE_AFK_TIMEOUT_MS
• CLAUDE_ASYNC_AGENT_STALL_TIMEOUT_MS: Default 600,000ms (10 minutes).
• CLAUDE_BYTE_STREAM_IDLE_TIMEOUT_MS
• CLAUDE_CODE_CONNECT_TIMEOUT_MS

Frequently asked questions

All variables, searchable: Claude Code environment variables.