context-manager

Context Manager

Prevent information loss when your Claude Code context window fills up. Automatically tracks usage, saves state, and restores after restart.

When to Activate

• User says /ctx or /ctx save or /ctx check
• User asks about context usage or remaining space
• User is working on a long task that might exhaust context
• Before starting a large task (reading many files, big implementation)

The Problem

Claude Code has a finite context window. When it fills up:

• The system compresses earlier messages (lossy)
• You lose working state, partial progress, and nuanced context
• Multi-step tasks break halfway through
• You repeat work you already did

Instructions

/ctx check — Check Current Usage

Read the context-usage.json file (updated by Claude Code hooks):

cat .claude/state/context-usage.json 2>/dev/null

Report to the user:

• Green (>60% remaining): Plenty of room. Work freely.
• Yellow (40-60% remaining): Getting warm. Save state before starting big tasks.
• Red (<40% remaining): Save state now. Consider restarting before continuing.

If no tracking file exists, guide setup (see Setup section).

/ctx save — Save Current State

Capture everything needed to resume after a restart:

1. Create state file at .claude/state/assistant-state.md:

# Assistant State

**Saved**: {ISO timestamp}
**Reason**: {why saving — manual save, low context, task checkpoint}

## Current Task
{What you're working on right now}

## What's Done
{Completed steps, with file paths and commit hashes}

## What's Next
{Remaining steps, in order}

## Key Context
{Important facts that would be lost — variable names, design decisions,
 user preferences expressed during this session, error messages that
 led to the current approach}

## Open Files
{Files currently being worked on, with relevant line ranges}

1. Confirm save — tell the user what was captured

/ctx restore — Restore After Restart

At session start, check for saved state: