speckit-drift

name	speckit-drift
description	Analyze drift between specs and implementation. Compares requirements against code to find divergence.
compatibility	Requires spec-kit project structure with .specify/ directory
metadata	{"author":"github-spec-kit","source":"sync:commands/analyze.md"}

Spec Sync: Analyze Drift

Analyze drift between specifications and implementation. This command compares your spec requirements (FR-, SC-, acceptance scenarios) against the actual codebase to identify where they've diverged.

User Input

$ARGUMENTS

Context

Read the project structure to understand the codebase:

• Specs directory: Look for specs/*/spec.md files
• Implementation: Look for source files matching the project type

Steps

1. Discover Specs

Find all spec files in the project:

find specs -name "spec.md" -type f 2>/dev/null | sort

For each spec, extract:

• Spec ID (directory name)
• Title (first heading)
• Functional requirements (FR-001, FR-002, etc.)
• Success criteria (SC-001, SC-002, etc.)
• Key acceptance scenarios

2. Analyze Implementation

For each spec, determine:

• Which requirements have corresponding implementation
• Which requirements appear unimplemented
• Which code features exist without spec coverage

Use these heuristics:

• CLI commands mentioned in spec → Check for corresponding Command classes
• Services mentioned in spec → Check for corresponding Service classes
• Entities/models mentioned → Check for corresponding entity files
• Test coverage → Check for corresponding test files

3. Detect Unspecced Code

Find code that doesn't match any spec:

• Commands not referenced in any spec
• Services not referenced in any spec
• Features that evolved beyond their spec

4. Generate Drift Report

Output a structured report in this format:

# Spec Drift Report

Generated: [timestamp]
Project: [project name]

## Summary

| Category | Count |
|----------|-------|
| Specs Analyzed | X |
| Requirements Checked | X |
| ✓ Aligned | X (Y%) |
| ⚠️ Drifted | X (Y%) |
| ✗ Not Implemented | X (Y%) |
| 🆕 Unspecced Code | X |

## Detailed Findings

### Spec: [spec-id] - [title]

#### Aligned ✓
- FR-001: [description] → [implementation location]

#### Drifted ⚠️
- FR-002: Spec says "[spec text]" but code does "[actual behavior]"
  - Location: [file:line]
  - Severity: [minor|moderate|major]

#### Not Implemented ✗
- FR-003: [description]

### Unspecced Code 🆕

| Feature | Location | Lines | Suggested Spec |
|---------|----------|-------|----------------|
| [feature] | [path] | [count] | [spec-XXX] |

## Inter-Spec Conflicts

[List any contradictions between specs]

## Recommendations

1. [First recommendation]
2. [Second recommendation]

5. Write Report

Save the report to:

• .specify/sync/drift-report.md (human-readable)
• .specify/sync/drift-report.json (machine-readable)

Output Format

The JSON report should follow this schema:

{
  "generated": "ISO-8601 timestamp",
  "project": "project name",
  "summary": {
    "specs_analyzed": 0,
    "requirements_checked": 0,
    "aligned": 0,
    "drifted": 0,
    "not_implemented": 0,
    "unspecced_features": 0
  },
  "specs": [
    {
      "id": "spec-id",
      "title": "Spec Title",
      "aligned": ["FR-001", "FR-002"],
      "drifted": [
        {
          "requirement": "FR-003",
          "spec_text": "what spec says",
          "actual": "what code does",
          "location": "path/to/file.cs:123",
          "severity": "moderate"
        }
      ],
      "not_implemented": ["FR-004"]
    }
  ],
  "unspecced": [
    {
      "feature": "FeatureName",
      "location": "path/to/file",
      "lines": 150,
      "suggested_spec": "spec-013"
    }
  ],
  "conflicts": []
}

Example Usage

/speckit.sync.analyze

/speckit.sync.analyze --spec 011-register-write

/speckit.sync.analyze --json

Notes

• This is a read-only analysis - no files are modified
• Large codebases may take time to analyze
• Use --spec <id> to analyze a single spec
• Use --json for machine-readable output only