Pattern Extraction

Pattern Extraction automatically captures valuable development patterns from your Claude Code sessions and shell interactions. As you solve problems, NC learns and makes those patterns available for reuse across projects. This is a Pro tier feature for cross-project sharing.

How It Works

Your Development Activity
┌──────────────────────────────────────────────────────────┐
│                                                          │
│  ┌──────────┐  ┌──────────┐  ┌──────────────────────┐  │
│  │ Commands  │  │ Code     │  │ Claude Code Sessions │  │
│  │ Executed  │  │ Written  │  │ (JSONL parsed)       │  │
│  └─────┬────┘  └────┬─────┘  └──────────┬───────────┘  │
│        └─────────────┼───────────────────┘              │
│                      │                                   │
│              ┌───────┴───────┐                           │
│              │ Pattern Sync  │                           │
│              │ Manager       │                           │
│              │ (SHA256 dedup)│                           │
│              └───────┬───────┘                           │
│                      │                                   │
│           ┌──────────┴──────────┐                       │
│           │  Two-Tier Storage   │                       │
│           │  Global + Per-Project│                       │
│           └─────────────────────┘                       │
└──────────────────────────────────────────────────────────┘

Pattern Categories

NC classifies patterns into 7 categories:

Category	Description	Example
code_pattern	Reusable code structures	Graceful HTTP shutdown
architecture	System design patterns	Event-driven integration
best_practice	Proven approaches	SQLite WAL mode for concurrency
gotcha	Common pitfalls	WSL2 process detection quirks
solution	Problem-specific fixes	Goroutine leak fix
workflow	Process patterns	Pre-commit validation hook
configuration	Config patterns	Docker health check settings

Quick Start

List Your Patterns

ncmd patterns list

Patterns (showing top 20)
═════════════════════════

  Go Graceful HTTP Shutdown                    code_pattern
  Language: go | Used: 4 times | Success: 100%
  Tags: go, http, graceful-shutdown
  ──────────────────────────────────────

  Fix WSL2 Process Detection                   solution
  Language: go | Used: 2 times | Success: 100%
  Tags: wsl2, process, cross-platform

Search Patterns

ncmd patterns search "error handling"

Apply a Pattern

Mark a pattern as used (tracks effectiveness):

ncmd patterns apply a1b2c3d4

View Statistics

ncmd patterns stats

Pattern Statistics
══════════════════

Total Patterns: 42

By Category:
  code_pattern:    15 (35.7%)
  solution:        10 (23.8%)
  best_practice:    8 (19.0%)

By Language:
  go:              22 (52.4%)
  python:           8 (19.0%)
  typescript:        6 (14.3%)

Average Success Rate: 94.2%

CLI Commands

Command	Description
ncmd patterns list	Display patterns (top 20 by default)
ncmd patterns list --global	Show all patterns
ncmd patterns list --category <cat>	Filter by category
ncmd patterns list --language <lang>	Filter by language
ncmd patterns search <query>	Full-text search
ncmd patterns apply <id>	Mark pattern as used
ncmd patterns sync	Export to global store (Pro tier)
ncmd patterns stats	View aggregated statistics
ncmd patterns remove <id>	Delete a pattern

Pattern IDs support partial matching (first 4+ characters).

Automatic Capture

When the NC daemon is running, patterns are captured automatically from:

1. Claude Code sessions - The Harvester parses JSONL session files, extracting prompts and outcomes (file changes, git commits, tool results)
2. Shell commands - Command execution patterns with success/failure tracking
3. Code changes - Significant code patterns during file monitoring

Value Estimation

Each pattern receives an estimated time-savings value:

Pattern Type	Estimated Minutes Saved
Fix	30 min
Optimization	20 min
Refactor / Architecture	15 min
Function	10 min
Command	5 min (10 for pipelines)

Patterns saving 30+ minutes trigger high-value notifications through Active Alerts.

Cross-Project Sharing (Pro)

NC scores patterns against your current project context using multiple factors:

Factor	Weight	Description
Language match	0.40	Primary language match
Framework match	0.30	Framework match
Tag overlap	0.20	Shared tags
Success rate	0.10	Historical reliability
Recency	0.10	Recently used patterns

Only patterns scoring above 0.30 are recommended. Top 10 per project.

# Sync project patterns to global store
ncmd patterns sync

# Other projects automatically get relevant recommendations

Storage

Patterns use a two-tier storage layout:

~/.neural-commander/
└── patterns/
    ├── global/
    │   └── patterns.json    # Cross-project patterns
    └── projects/
        ├── project-a/
        │   └── learnings/   # Project-specific
        └── project-b/
            └── learnings/

Deduplication uses SHA256 hashing of content. Duplicate patterns increment usage count instead of creating copies.

API Access

Patterns are available via the NC REST API on port 7669:

# List all patterns
curl http://localhost:7669/api/patterns

# Filter by category
curl "http://localhost:7669/api/patterns?category=code_pattern"

# Search by keyword
curl "http://localhost:7669/api/patterns?q=error+handling"

# Add a pattern
curl -X POST http://localhost:7669/api/patterns \
  -H "Content-Type: application/json" \
  -d '{"title":"My Pattern","content":"code here","category":"code_pattern"}'

# Track usage
curl -X POST http://localhost:7669/api/patterns/a1b2c3d4/apply

# Get statistics
curl http://localhost:7669/api/patterns/stats

# Get relevant patterns for a project
curl -X POST http://localhost:7669/api/patterns/relevant \
  -d '{"language":"go","tags":["api","daemon"]}'

Troubleshooting

No Patterns Showing

1. Ensure the daemon is running: ncmd daemon status
2. Check with --global flag: ncmd patterns list --global
3. Work in a Claude Code session with the daemon running to start capturing

Sync Fails with Tier Error

Cross-project sync requires Pro tier. Use ncmd patterns list for local patterns on Free tier.

Pattern Not Being Captured

1. Verify harvester access: ls ~/.claude/projects/
2. Check harvest window (default: last 7 days)
3. Prompts shorter than 10 or longer than 50,000 characters are skipped

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Pattern Extraction integrates with Session Intelligence for session data and Active Alerts for high-value pattern notifications.