[FEATURE] Auto-compact on idle timeout

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• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Feature Request: Auto-compact on idle timeout

Summary

Add a configurable idle timeout that automatically runs /compact on a Claude Code session when no user input or tool activity has occurred for a specified number of minutes.

Motivation

Long-running Claude Code sessions accumulate context over time. When a session sits idle — the user steps away, gets on a call, or switches tasks — the context window continues to hold everything from the session, consuming tokens unnecessarily when the conversation resumes.

Currently, users must remember to manually run /compact before context gets too large. In practice this rarely happens, and sessions frequently hit context limits mid-task.

An automatic idle-triggered compact would solve this transparently.

Proposed Behavior

• Add a settings.json option, e.g.:

``json
"idleCompactMinutes": 15
``

• If no user input and no tool activity occurs for that duration, Claude Code automatically runs /compact
• A brief notice is shown when the session resumes: "Session was compacted after 15 minutes of inactivity."
• Setting 0 or omitting the key disables the feature (opt-in)

Why This Is Hard to Implement Today Without Native Support

The detection side is approximatable via hooks (writing a timestamp on PostToolUse / UserPromptSubmit and checking it from a cron job). However, there is currently no way to inject a /compact command into a running session from outside the process. Native support is required.

Expected Benefit

• Reduces mid-session context limit surprises
• Lowers token costs for users with long-running sessions
• No user action required — works transparently in the background

Environment

• Platform: macOS
• Claude Code CLI
• Relevant setting location: ~/.claude/settings.json

Proposed Solution

Proposed Behavior
Add a settings.json option, e.g.:
"idleCompactMinutes": 15
If no user input and no tool activity occurs for that duration, Claude Code automatically runs /compact
A brief notice is shown when the session resumes: "Session was compacted after 15 minutes of inactivity."
Setting 0 or omitting the key disables the feature (opt-in)

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_