spec-lock

name	spec-lock
description	Bi-directional code and documentation synchronizer. Use when editing code that affects specifications, API contracts, or documentation. Prevents documentation rot by maintaining sync between implementation and docs. Automatically detects drift and suggests updates.
version	1.0.0
author	Essential 2026 Suite
tags	["documentation","sync","specs","maintenance","drift"]
trigger_patterns	["update documentation","check spec sync","documentation drift","sync specs","spec lock","update spec","check docs","documentation out of date","maintain documentation"]
allowed_tools	["Bash","Read","Write","Edit"]

Spec-Lock: Documentation Synchronization

Overview

Spec-Lock prevents documentation rot by maintaining bi-directional sync between code and specifications. It treats documentation as executable code that must stay synchronized with implementation.

The Problem It Solves

Documentation Rot: In agentic workflows, code evolves faster than docs. Users hate writing documentation, and agents frequently ignore old instructions.

Spec-Lock Solution: Automatic synchronization that detects drift and keeps context perfectly synced with reality.

How It Works

1. Post-Edit Analysis (PostToolUse Hook)

Every time a file is edited:

• Analyzes semantic intent of the change
• Compares against CLAUDE.md and SPEC.md
• Detects drift between code and docs

2. Conflict Detection

Two scenarios trigger sync:

Scenario A: Code Drift

• Code violates the spec (e.g., wrong auth method)
• Plugin asks: "Revert code or update spec?"

Scenario B: Spec Evolution

• Code introduces new logic not in spec
• Plugin asks: "Update SPEC.md to match code?"

3. Auto-Update

Uses headless Claude to:

• Generate documentation patches
• Update dependent docs automatically
• Maintain knowledge graph of dependencies

When to Use

Activate Spec-Lock when:

• Changing API endpoints or parameters
• Modifying authentication flows
• Updating database schemas
• Changing configuration values
• Implementing new features
• Refactoring existing code

Usage

Automatic Mode

With PostToolUse hooks:

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit(*)|Write(*)",
        "command": "python3 /a0/usr/plugins/spec-lock/spec-lock.py --check"
      }
    ]
  }
}

Manual Commands

# Check a file for drift
python3 /a0/usr/plugins/spec-lock/spec-lock.py --check <file>

# Register a new dependency
python3 /a0/usr/plugins/spec-lock/spec-lock.py --register <code> <spec> [priority]

# Show sync status
python3 /a0/usr/plugins/spec-lock/spec-lock.py --status

# Force full sync
python3 /a0/usr/plugins/spec-lock/spec-lock.py --sync

Configuration

Priority Rules

Create /a0/usr/plugins/spec-lock/spec-priorities.yaml:

files:
  "src/auth/**":
    spec_source: "AUTH_SPEC.md"
    priority: code  # Code wins (security)
  
  "docs/api/**":
    spec_source: "API_SPEC.md"
    priority: spec  # Spec wins (contracts)
  
  "src/models/**":
    spec_source: "DATA_MODEL.md"
    priority: ask   # Always ask user

Priority Options:

• code: Implementation is source of truth
• spec: Documentation is source of truth
• ask: Prompt user for decision

Drift Detection

Spec-Lock detects these drift types:

Function Signature Mismatch

// Code has:
function createUser(name, email, role)

// Spec says:
function createUser(name, email)
// DRIFT: 'role' parameter not documented

API Endpoint Changes

// Code changed from:
POST /api/v1/users

// To:
POST /api/v2/users
// DRIFT: Version change not in API_SPEC.md

Configuration Changes

// Code changed:
const timeout = 5000;  // Was: 30000

// Spec still says:
"Request timeout: 30 seconds"
// DRIFT: Config value changed

Knowledge Graph

SQLite database tracks dependencies:

CREATE TABLE spec_dependencies (
    code_file TEXT,
    spec_file TEXT,
    last_sync TIMESTAMP,
    drift_detected BOOLEAN,
    priority TEXT
);

Example Dependencies:

• src/auth/login.ts → AUTH_SPEC.md
• src/api/users.js → API_SPEC.md
• src/models/user.js → DATA_MODEL.md

Sample Workflow

Developer Edits Authentication

# Developer changes JWT expiry
vim src/auth/login.ts
# const expiry = '1h';  # Changed from '24h'

Spec-Lock Detects Drift

⚠️  DRIFT DETECTED in src/auth/login.ts

AUTH_SPEC.md says:
  "Session tokens expire after 24 hours"

Code implements:
  "Session tokens expire after 1 hour"

Priority: CODE WINS (security)
Auto-updating AUTH_SPEC.md...
✅ Documentation synchronized

Sync Status Updated

📊 SYNC STATUS:
  Total Dependencies: 47
  In Sync: 47
  Drifted: 0
  Last Sync: 2026-02-12 13:00:00

Integration

With Debt-Sentinel

Spec-Lock runs after Debt-Sentinel clears edits:

1. Debt-Sentinel: Check for anti-patterns
2. Edit allowed to proceed
3. Spec-Lock: Check for doc drift
4. Auto-sync if possible

With Compound Engineering

Part of enhancement pipeline Level 4:

Level 4: Documentation Sync
  └─ Update all affected specs
  └─ Generate migration guides
  └─ Verify sync status

Success Metrics

• Sync Rate: % of dependencies in sync
• Drift Detection Time: Time to detect changes
• Auto-Resolution Rate: % resolved automatically
• Documentation Freshness: Average age of specs

Troubleshooting

Database Locked

rm /a0/usr/plugins/spec-lock/spec_dependencies.db

Missing Dependencies

# Register manually
python3 /a0/usr/plugins/spec-lock/spec-lock.py --register src/api/users.js API_SPEC.md spec

False Positives

Adjust priority rules in spec-priorities.yaml:

files:
  "src/internal/**":
    priority: code  # Internal tools don't need strict spec sync

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Part of the Essential 2026 Plugin Suite