[DOCS] Background shell docs omit memory-pressure reaping and `CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP`

Documentation Type

Missing documentation (feature not documented)

Documentation Location

https://code.claude.com/docs/en/tools-reference

Section/Topic

Bash tool background tasks, agent view shell jobs, and environment variables.

Current Documentation

The tools reference currently says:

For long-running processes such as dev servers or watch builds, Claude can set run_in_background: true to start the command as a background task and continue working while it runs. List and stop background tasks with /tasks.

The agent view page describes shell jobs:

The command runs as a PTY-backed job and appears as a row in agent view, with the most recent line of output as its status.

The environment variables page documents related background waits such as:

CLAUDE_CODE_PRINT_BG_WAIT_CEILING_MS | Maximum time in milliseconds that non-interactive mode with the -p flag waits after the final turn for background subagents and workflows whose result is part of the output.

What's Wrong or Missing?

Claude Code v2.1.193 added automatic memory-pressure reaping for idle background shell commands, with an opt-out environment variable: CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP=1.

The current docs do not explain:

• that idle background shell commands may be reaped under memory pressure
• what counts as an idle background shell command
• how this affects /tasks, agent view shell jobs, and Bash run_in_background
• how to disable the behavior with CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP=1
• where users should look when a long-running idle shell disappears

Suggested Improvement

Add a note to the Bash/background task docs:

Claude Code may automatically stop idle background shell commands under memory pressure. If you need to keep idle background shell commands alive even under pressure, set CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP=1.

Also add CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP to the environment variables reference, including the default behavior and any supported values.

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Context |
|------|---------|
| https://code.claude.com/docs/en/tools-reference | Describes Bash run_in_background but not memory-pressure reaping |
| https://code.claude.com/docs/en/agent-view | Describes background shell jobs but not idle reaping under memory pressure |
| https://code.claude.com/docs/en/env-vars | Omits CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP |

Total scope: 3 pages affected

Version context: Claude Code v2.1.193 release note: "Added automatic memory-pressure reaping for idle background shell commands (disable with CLAUDE_CODE_DISABLE_BG_SHELL_PRESSURE_REAP=1)."