Drift Analysis

Drift Analysis

Knowledge and patterns for analyzing project state, detecting plan drift, and creating prioritized reconstruction plans.

Architecture Overview

/drift-detect
        │
        ├─→ collectors.js (pure JavaScript)
        │   ├─ scanGitHubState()
        │   ├─ analyzeDocumentation()
        │   └─ scanCodebase()
        │
        └─→ plan-synthesizer (Opus)
            └─ Deep semantic analysis with full context

Data collection: Pure JavaScript (no LLM overhead) Semantic analysis: Single Opus call with complete context

Drift Detection Patterns

Types of Drift

Plan Drift: When documented plans diverge from actual implementation

• PLAN.md items remain unchecked for extended periods
• Roadmap milestones slip without updates
• Sprint/phase goals not reflected in code changes

Documentation Drift: When documentation falls behind implementation

• New features exist without corresponding docs
• README describes features that don't exist
• API docs don't match actual endpoints

Issue Drift: When issue tracking diverges from reality

• Stale issues that no longer apply
• Completed work without closed issues
• High-priority items neglected

Scope Drift: When project scope expands beyond original plans

• More features documented than can be delivered
• Continuous addition without completion
• Ever-growing backlog with no pruning

Detection Signals

HIGH-CONFIDENCE DRIFT INDICATORS:
- Milestone 30+ days overdue with open issues
- PLAN.md  60 days
- README features not found in codebase

MEDIUM-CONFIDENCE INDICATORS:
- Documentation files unchanged for 180+ days
- Draft PRs open > 30 days
- Issue themes don't match code activity
- Large gap between documented and implemented features

LOW-CONFIDENCE INDICATORS:
- Many TODOs in codebase
- Stale dependencies
- Old git branches not merged

Prioritization Framework

Priority Calculation

function calculatePriority(item, weights) {
  let score = 0;

  // Severity base score
  const severityScores = {
    critical: 15,
    high: 10,
    medium: 5,
    low: 2
  };
  score += severityScores[item.severity] || 5;

  // Category multiplier
  const categoryWeights = {
    security: 2.0,    // Security issues get 2x
    bugs: 1.5,        // Bugs get 1.5x
    infrastructure: 1.3,
    features: 1.0,
    documentation: 0.8
  };
  score *= categoryWeights[item.category] || 1.0;

  // Recency boost
  if (item.createdRecently) score *= 1.2;

  // Stale penalty (old items slightly deprioritized)
  if (item.daysStale > 180) score *= 0.9;

  return Math.round(score);
}

Time Bucket Thresholds

| Bucket | Criteria | Max Items | |--------|----------|-----------| | Immediate | severity=critical OR priority >= 15 | 5 | | Short-term | severity=high OR priority >= 10 | 10 | | Medium-term | priority >= 5 | 15 | | Backlog | everything else | 20 |

Priority Weights (Default)

security: 10     # Security issues always top priority
bugs: 8          # Bugs affect users directly
features: 5      # New functionality
documentation: 3 # Important but not urgent
tech-debt: 4     # Keeps codebase healthy

Cross-Reference Patterns

Document-to-Code Matching

// Fuzzy matching for feature names
function featureMatch(docFeature, codeFeature) {
  const normalize = s => s
    .toLowerCase()
    .replace(/[-_\s]+/g, '')
    .replace(/s$/, ''); // Remove trailing 's'

  const docNorm = normalize(docFeature);
  const codeNorm = normalize(codeFeature);

  return docNorm.includes(codeNorm) ||
         codeNorm.includes(docNorm) ||
         levenshteinDistance(docNorm, codeNorm)  90 days inactive)
- Theme analysis from titles

### Documentation Data
- Parsed README, PLAN.md, CLAUDE.md, CHANGELOG.md
- Checkbox completion counts
- Section analysis
- Feature lists

### Code Data
- Directory structure
- Framework detection
- Test framework presence
- Health indicators (CI, linting, tests)

## Semantic Analysis (Opus)

The plan-synthesizer receives all collected data and performs:

1. **Cross-referencing**: Match documented features to implementation
2. **Drift identification**: Find divergence patterns
3. **Gap analysis**: Identify what's missing
4. **Prioritization**: Context-aware ranking
5. **Report generation**: Actionable recommendations

## Example Input/Output

### Collected Data (from collectors.js)

```json
{
  "github": {
    "issues": [...],
    "categorized": { "bugs": [...], "features": [...] },
    "stale": [...]
  },
  "docs": {
    "files": { "README.md": {...}, "PLAN.md": {...} },
    "checkboxes": { "total": 15, "checked": 3 }
  },
  "code": {
    "frameworks": ["Express"],
    "health": { "hasTests": true, "hasCi": true }
  }
}

Analysis Output (from plan-synthesizer)

# Reality Check Report

## Executive Summary
Project has moderate drift: 8 stale priority issues and 20% plan completion.
Strong code health (tests + CI) but documentation lags implementation.

## Drift Analysis
### Priority Neglect
**Severity**: high
8 high-priority issues inactive for 60+ days...

## Prioritized Plan
### Immediate
1. Close #45 (already implemented)
2. Update README API section...

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: agent-sh
• Source: agent-sh/agentsys
• License: MIT
• Homepage: https://agent-sh.github.io/agentsys/

Install and usage instructions live in the source repository linked above.