SuperClaude/docs/Reference/claude-code-history-management.md

Claude Code Conversation History Management Research

Research Date: 2025-10-09 Purpose: Understand .jsonl file structure, performance impact, and establish rotation policy

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1. Official Documentation & Purpose

.jsonl File Structure

Location: ~/.claude/projects/{project-directory}/

Data Structure (from analysis of actual files):

{
  "type": "summary|file-history-snapshot|user|assistant|system|tool_use|tool_result|message",
  "timestamp": "ISO-8601 timestamp",
  "cwd": "/absolute/path/to/working/directory",
  "sessionId": "uuid",
  "gitBranch": "branch-name",
  "content": "message content or command",
  "messageId": "uuid for message tracking"
}

Key Message Types (from 2.6MB conversation analysis):

• message (228): Container for conversation messages
• assistant (228): Claude's responses
• user (182): User inputs
• tool_use (137): Tool invocations
• tool_result (137): Tool execution results
• text (74): Text content blocks
• file-history-snapshot (39): File state tracking
• thinking (31): Claude's reasoning process
• system (12): System-level messages

File History Snapshot Purpose

{
  "type": "file-history-snapshot",
  "messageId": "uuid",
  "snapshot": {
    "messageId": "uuid",
    "trackedFileBackups": {},
    "timestamp": "ISO-8601"
  },
  "isSnapshotUpdate": false
}

Purpose (inferred from structure):

• Tracks file states at specific conversation points
• Enables undo/redo functionality for file changes
• Provides rollback capability for edits
• Note: No official documentation found on this feature

Conversation Loading Behavior

Official Best Practices (source):

• "All conversations are automatically saved locally with their full message history"
• "When resuming, the entire message history is restored to maintain context"
• "Tool usage and results from previous conversations preserved"

Resume Commands:

• --continue: Automatically continue most recent conversation
• /resume: Show list of recent sessions and choose one
• Session ID specification: Resume specific conversation

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2. Performance Impact

Known Issues from GitHub

Issue #5024: History Accumulation Causing Performance Issues

Status: Open (Major Issue) URL: https://github.com/anthropics/claude-code/issues/5024

Reported Problems:

• File sizes growing to "hundreds of MB or more"
• Slower application startup times
• System performance degradation
• No automatic cleanup mechanism
• One user reported file size of 968KB+ continuously growing

Current Workaround:

• Manual editing of .claude.json (risky - can break configurations)
• claude history clear (removes ALL history across ALL projects)

Issue #7985: Severe Memory Leak

Status: Critical URL: https://github.com/anthropics/claude-code/issues/7985

Reported Problems:

• Context accumulation causing massive memory usage
• Memory leaks with objects not garbage collected
• One user reported ~570GB of virtual memory usage
• Long-running sessions become unusable

Issue #8839: Conversation Compaction Failure

Status: Regression (after undo/redo feature) URL: https://github.com/anthropics/claude-code/issues/8839

Impact:

• Claude Code can no longer automatically compact long conversations
• "Too long" errors after conversation history navigation feature added
• Conversations become unmanageable without manual intervention

Issue #8755: /clear Command Not Working

Status: Bug URL: https://github.com/anthropics/claude-code/issues/8755

Impact:

• /clear command stopped functioning for some users
• "Clear Conversations" menu option non-functional
• Users cannot reset context window as recommended

Actual Performance Data (Your Environment)

Current State (as of 2025-10-09):

• Total agiletec project: 33MB (57 conversation files)
• Largest file: 2.6MB (462 lines)
• Average file: ~580KB
• Files >1MB: 3 files
• Total across all projects: ~62MB

Age Distribution:

• Files older than 30 days: 0
• Files older than 7 days: 4
• Most files: <7 days old

Comparison to Other Projects:

33M   agiletec (57 files) - Most active
14M   SSD-2TB project
6.3M  tokium
2.6M  bunseki

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3. Official Retention Policies

Standard Retention (Consumer)

Source: Anthropic Privacy Center

• Prompts/Responses: Up to 30 days in back-end logs
• Deleted chats: Immediately removed from UI, purged within 30 days
• API logs: Reducing to 7 days starting September 15, 2025 (from 30 days)

Enterprise Controls

Source: Custom Data Retention Controls

• Minimum retention: 30 days
• Retention start: Last observed activity (last message or project update)
• Custom periods: Available for organizations

Local Storage (No Official Policy)

Finding: No official documentation found regarding:

• Recommended local .jsonl file retention periods
• Automatic cleanup of old conversations
• Performance thresholds for file sizes
• Safe deletion procedures

Current Tools:

• claude history clear: Removes ALL history (all projects, destructive)
• No selective cleanup tools available
• No archive functionality

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4. Best Practices (Official & Community)

Official Recommendations

Context Management

Source: Claude Code Best Practices

Key Guidelines:

1. Use /clear frequently: "Reset context window between tasks"
2. Scope conversations: "One project or feature per conversation"
3. Clear before switching: "/clear before fixing bugs to prevent context pollution"
4. Don't rely on long context: "Claude's context window can fill with irrelevant conversation"

Quote: "During long sessions, Claude's context window can fill with irrelevant conversation, file contents, and commands which can reduce performance, so use the /clear command frequently between tasks to reset the context window."

CLAUDE.md Strategy

• Persistent context: Use CLAUDE.md files for stable instructions
• Auto-loaded: "Claude automatically pulls into context when starting"
• Hierarchy: Global (~/.claude/CLAUDE.md) → Workspace → Project
• Refinement: "Take time to experiment and determine what produces best results"

When to Restart vs /clear

Source: Community Best Practices

Use /clear when:

• Starting new task/feature
• Switching between features
• Context becomes polluted
• Before bug fixing

Restart session when:

• Switching projects
• Updating CLAUDE.md files
• Experiencing session issues
• Memory usage high

Community Strategies

Conversation Organization

Pattern: "Scope a chat to one project or feature"

• Start conversation for specific goal
• Use /clear when goal complete
• Don't mix unrelated tasks in same conversation

Context Optimization

Pattern: "Avoid extensive, unrefined context"

• Iterate on CLAUDE.md effectiveness
• Remove ineffective instructions
• Test and refine periodically

Incognito Mode for Sensitive Work

Pattern: "Ghost icon for temporary conversations"

• Not saved to chat history
• No contribution to context memory
• Useful for experimental or sensitive work

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5. Recommended Rotation Policy

Immediate Actions (No Risk)

1. Delete Very Old Conversations (>30 days)

# Backup first
mkdir -p ~/.claude/projects-archive/$(date +%Y-%m)

# Find and archive
find ~/.claude/projects/ -name "*.jsonl" -mtime +30 -type f \
  -exec mv {} ~/.claude/projects-archive/$(date +%Y-%m)/ \;

Rationale:

• Aligns with Anthropic's 30-day back-end retention
• Minimal functionality loss (context rarely useful after 30 days)
• Significant space savings

2. Archive Project-Specific Old Conversations (>14 days)

# Per-project archive
mkdir -p ~/.claude/projects-archive/agiletec/$(date +%Y-%m)

find ~/.claude/projects/-Users-kazuki-github-agiletec -name "*.jsonl" -mtime +14 -type f \
  -exec mv {} ~/.claude/projects-archive/agiletec/$(date +%Y-%m)/ \;

Rationale:

• 14 days provides buffer for resumed work
• Most development tasks complete within 2 weeks
• Easy to restore if needed

Periodic Maintenance (Weekly)

3. Identify Large Files for Manual Review

# Find files >1MB
find ~/.claude/projects/ -name "*.jsonl" -type f -size +1M -exec ls -lh {} \;

# Review and archive if not actively used

Criteria for Archival:

• File >1MB and not modified in 7 days
• Completed feature/project conversations
• Debugging sessions that are resolved

Aggressive Cleanup (Monthly)

4. Archive All Inactive Conversations (>7 days)

# Monthly archive
mkdir -p ~/.claude/projects-archive/$(date +%Y-%m)

find ~/.claude/projects/ -name "*.jsonl" -mtime +7 -type f \
  -exec mv {} ~/.claude/projects-archive/$(date +%Y-%m)/ \;

When to Use:

• Project directory >50MB
• Startup performance degraded
• Running low on disk space

Emergency Cleanup (Performance Issues)

5. Nuclear Option - Keep Only Recent Week

# BACKUP EVERYTHING FIRST
tar -czf ~/claude-history-backup-$(date +%Y%m%d).tar.gz ~/.claude/projects/

# Keep only last 7 days
find ~/.claude/projects/ -name "*.jsonl" -mtime +7 -type f -delete

When to Use:

• Claude Code startup >10 seconds
• Memory usage abnormally high
• Experiencing Issue #7985 symptoms

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6. Proposed Automated Solution

Shell Script: claude-history-rotate.sh

#!/usr/bin/env bash
# Claude Code Conversation History Rotation
# Usage: ./claude-history-rotate.sh [--dry-run] [--days N]

set -euo pipefail

DAYS=${DAYS:-30}
DRY_RUN=false
ARCHIVE_BASE=~/.claude/projects-archive

# Parse arguments
while [[ $# -gt 0 ]]; do
  case $1 in
    --dry-run) DRY_RUN=true; shift ;;
    --days) DAYS="$2"; shift 2 ;;
    *) echo "Unknown option: $1"; exit 1 ;;
  esac
done

# Create archive directory
ARCHIVE_DIR="$ARCHIVE_BASE/$(date +%Y-%m)"
mkdir -p "$ARCHIVE_DIR"

# Find old conversations
OLD_FILES=$(find ~/.claude/projects/ -name "*.jsonl" -mtime "+$DAYS" -type f)

if [[ -z "$OLD_FILES" ]]; then
  echo "No files older than $DAYS days found."
  exit 0
fi

# Count and size
FILE_COUNT=$(echo "$OLD_FILES" | wc -l | tr -d ' ')
TOTAL_SIZE=$(echo "$OLD_FILES" | xargs du -ch | tail -1 | awk '{print $1}')

echo "Found $FILE_COUNT files older than $DAYS days ($TOTAL_SIZE total)"

if [[ "$DRY_RUN" == "true" ]]; then
  echo "DRY RUN - Would archive:"
  echo "$OLD_FILES"
  exit 0
fi

# Archive files
echo "$OLD_FILES" | while read -r file; do
  mv "$file" "$ARCHIVE_DIR/"
  echo "Archived: $(basename "$file")"
done

echo "✓ Archived $FILE_COUNT files to $ARCHIVE_DIR"

Cron Job Setup (Optional)

# Add to crontab (monthly cleanup)
# 0 3 1 * * /Users/kazuki/.local/bin/claude-history-rotate.sh --days 30

# Or use launchd on macOS
cat > ~/Library/LaunchAgents/com.user.claude-history-rotate.plist <<'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.user.claude-history-rotate</string>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/kazuki/.local/bin/claude-history-rotate.sh</string>
        <string>--days</string>
        <string>30</string>
    </array>
    <key>StartCalendarInterval</key>
    <dict>
        <key>Day</key>
        <integer>1</integer>
        <key>Hour</key>
        <integer>3</integer>
    </dict>
</dict>
</plist>
EOF

launchctl load ~/Library/LaunchAgents/com.user.claude-history-rotate.plist

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7. Monitoring & Alerts

Disk Usage Check Script

#!/usr/bin/env bash
# claude-history-check.sh

THRESHOLD_MB=100
PROJECTS_DIR=~/.claude/projects

TOTAL_SIZE_MB=$(du -sm "$PROJECTS_DIR" | awk '{print $1}')

echo "Claude Code conversation history: ${TOTAL_SIZE_MB}MB"

if [[ $TOTAL_SIZE_MB -gt $THRESHOLD_MB ]]; then
  echo "⚠️  WARNING: History size exceeds ${THRESHOLD_MB}MB threshold"
  echo "Consider running: claude-history-rotate.sh --days 30"

  # Find largest projects
  echo ""
  echo "Largest projects:"
  du -sm "$PROJECTS_DIR"/*/ | sort -rn | head -5
fi

Performance Indicators to Watch

1. Startup time: >5 seconds = investigate
2. File sizes: >2MB per conversation = review
3. Total size: >100MB across all projects = cleanup
4. Memory usage: >2GB during session = Issue #7985
5. Conversation length: >500 message pairs = use /clear

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8. Key Takeaways & Recommendations

Critical Findings

✅ Safe to Delete:

• Conversations >30 days old (aligns with Anthropic retention)
• Completed feature/project conversations
• Large files (>1MB) not accessed in 14+ days

⚠️ Caution Required:

• Active project conversations (<7 days)
• Files referenced in recent work
• Conversations with unfinished tasks

❌ Known Issues:

• No official cleanup tools (Issue #5024)
• Memory leaks in long sessions (Issue #7985)
• /clear command bugs (Issue #8755)
• Conversation compaction broken (Issue #8839)

Recommended Policy for Your Environment

Daily Practice:

• Use /clear between major tasks
• Scope conversations to single features
• Restart session if >2 hours continuous work

Weekly Review (Sunday):

# Check current state
du -sh ~/.claude/projects/*/

# Archive old conversations (>14 days)
claude-history-rotate.sh --days 14 --dry-run  # Preview
claude-history-rotate.sh --days 14            # Execute

Monthly Cleanup (1st of month):

# Aggressive cleanup (>30 days)
claude-history-rotate.sh --days 30

# Review large files
find ~/.claude/projects/ -name "*.jsonl" -size +1M -mtime +7

Performance Threshold Actions:

• Total size >50MB: Archive 30-day-old conversations
• Total size >100MB: Archive 14-day-old conversations
• Total size >200MB: Emergency cleanup (7-day retention)
• Startup >10s: Investigate memory leaks, consider Issue #7985

Future-Proofing

Watch for Official Solutions:

• claude history prune command (requested in #5024)
• Automatic history rotation feature
• Configurable retention settings
• Separate configuration from history storage

Community Tools:

• cclogviewer: View .jsonl files
• Consider contributing to #5024 discussion
• Monitor anthropics/claude-code releases

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9. References

Official Documentation

• Claude Code Best Practices
• How Long Do You Store My Data?
• Custom Data Retention Controls

GitHub Issues

• #5024: History accumulation causes performance issues
• #7985: Severe memory leak
• #8839: Conversation compaction failure
• #8755: /clear command not working

Community Resources

• Awesome Claude Code
• Claude Code Context Guide
• ClaudeLog Documentation

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Appendix: Current Environment Statistics

Generated: 2025-10-09 04:24 JST

Project Size Breakdown

33M   -Users-kazuki-github-agiletec (57 files)
14M   -Volumes-SSD-2TB (project count: N/A)
6.3M  -Users-kazuki-github-tokium
2.6M  -Users-kazuki-github-bunseki
1.9M  -Users-kazuki
1.9M  -Users-kazuki-github-superclaude
---
Total: ~62MB across all projects

agiletec Project Details

• Total conversations: 57
• Largest file: 2.6MB (d4852655-b760-4311-8f67-26f593f2403f.jsonl)
• Files >1MB: 3 files
• Avg file size: ~580KB
• Files >7 days: 4 files
• Files >30 days: 0 files

Immediate Recommendation

Status: ✅ Healthy (no immediate action required)

Reasoning:

• Total size (33MB) well below concern threshold (100MB)
• No files >30 days old
• Only 4 files >7 days old
• Largest file (2.6MB) within acceptable range

Next Review: 2025-10-16 (weekly check)