spec-ai 0.1.51

A versioned documentation layer for AI-assisted development

spec

A versioned documentation layer for AI-assisted development. spec maintains a separate Git repository of contextual documentation that helps AI agents understand your codebase without polluting your main Git history.

Why spec?

• AI-Optimized Context: Structured documentation designed for LLM consumption
• Version-Controlled Memory: AI agents can learn from past attempts and decisions
• Isolated Git History: Documentation changes don't clutter your main repository
• Scoped Context Windows: Load only relevant documentation to fit within token limits
• Rich Terminal UI: Beautiful, colorful interface with progress indicators
• Modular Architecture: Clean, testable codebase built for extensibility

Installation

pip install spec-cli

Quick Start

# Initialize spec in your project
spec init

# Generate documentation for files
spec gen src/models.py        # Single file
spec gen src/                 # Directory
spec gen .                    # Current directory (all files)

# Track documentation changes
spec add .
spec commit -m "Document authentication flow"

# View documentation status
spec status
spec log
spec diff

Features

✅ Core Features

• Project Initialization: spec init creates isolated Git repository structure
• Documentation Generation: spec gen creates structured documentation with templates
• Version Control: Full Git workflow (add, commit, status, log, diff)
• Template System: Customizable documentation templates via .spectemplate
• File Filtering: Smart filtering with .specignore patterns
• Rich Terminal UI: Beautiful interface with colors, progress bars, and styling
• Batch Processing: Generate documentation for entire directories
• File Type Detection: Support for 20+ programming languages and file types
• Conflict Resolution: Interactive handling of existing documentation
• Debug Mode: Comprehensive debugging with SPEC_DEBUG=1
• Modular Architecture: Clean, maintainable codebase with 80%+ test coverage

🔮 Future Features

• AI Documentation Generation: Replace placeholder content with AI-generated documentation
• Git Hook Integration: Auto-generate documentation on code changes
• Enhanced CLI: Advanced options and configuration management

How It Works

spec creates two directories:

• .spec/ - A bare Git repository (like .git)
• .specs/ - Working tree containing documentation

Your documentation mirrors your project structure:

project/
├── .spec/              # Bare Git repo for versioning
├── .specs/             # Documentation working tree
│   ├── src/
│   │   └── models/
│   │       ├── index.md
│   │       └── history.md
│   └── api/
│       └── users/
│           ├── index.md
│           └── history.md
├── .spectemplate       # Customizable templates
├── .specignore         # Ignore patterns
├── src/
│   └── models.py
└── api/
    └── users.py

Each source file gets a documentation directory with:

• index.md: Current understanding and specifications
• history.md: Evolution, decisions, and lessons learned

Commands

Core Commands

• spec init - Initialize spec in current directory
• spec gen <path> - Generate documentation for file(s) or directory
• spec add <path> - Stage documentation changes
• spec commit -m "message" - Commit documentation changes

View Documentation

• spec status - Show documentation status
• spec log [path] - Show documentation history
• spec diff [path] - Show uncommitted changes
• spec show <path> - Display documentation for a file (coming soon)

Future Commands

• spec regen <path> - Regenerate documentation (preserves history)
• spec agent-scope [options] - Export scoped context for AI agents

Advanced Usage

Custom Templates

Create a .spectemplate file to customize documentation format:

index:
  template: |
    # {{filename}}

    **Location**: {{filepath}}
    **Purpose**: {{purpose}}
    **Responsibilities**: {{responsibilities}}
    **Requirements**: {{requirements}}
    **Example Usage**: {{example_usage}}
    **Notes**: {{notes}}

history:
  template: |
    ## {{date}} - Initial Creation

    **Purpose**: Created initial specification for {{filename}}
    **Context**: {{context}}
    **Decisions**: {{decisions}}
    **Lessons Learned**: {{lessons}}

Environment Variables

Control spec behavior with environment variables:

• SPEC_DEBUG=1 - Enable debug output for troubleshooting
• SPEC_DEBUG_LEVEL=INFO|DEBUG|WARNING|ERROR - Set debug level
• SPEC_DEBUG_TIMING=1 - Enable operation timing

File Filtering

Use .specignore to exclude files from documentation generation:

# Ignore patterns
*.log
node_modules/
build/
*.min.js

Architecture

spec follows a clean, modular architecture built through a comprehensive refactoring:

Directory Structure

spec_cli/
├── cli/                     # Command-line interface layer
├── core/                    # Core business logic and workflow orchestration
├── git/                     # Git operations abstraction
├── templates/               # Template system for documentation generation
├── file_system/             # File system operations and path handling
├── config/                  # Configuration management
├── ui/                      # Rich terminal UI components
├── file_processing/         # Batch processing and conflict resolution
├── exceptions.py            # Custom exception hierarchy
└── logging/                 # Debug logging and timing

Key Design Principles

• Single Responsibility: Each module has a clear, focused purpose
• Dependency Injection: Services are easily testable and mockable
• Clean Interfaces: Well-defined boundaries between layers
• Rich Terminal UI: Beautiful, colorful interface throughout
• Comprehensive Testing: 80%+ test coverage across all modules

Development Setup

This project uses Poetry for dependency management and uv for virtual environments:

# Create virtual environment with uv
uv venv

# Activate virtual environment
source .venv/bin/activate  # On Unix/macOS
# or
.venv\Scripts\activate  # On Windows

# Install dependencies with poetry
poetry install

# Run tests with coverage (80% minimum required)
poetry run pytest tests/unit/ -v --cov=spec_cli --cov-report=term-missing --cov-fail-under=80

# Run type checking
poetry run mypy spec_cli/

# Run linting and formatting
poetry run ruff check --fix .
poetry run ruff format .

# Run all pre-commit hooks
poetry run pre-commit run --all-files

Use Cases

For AI Development

• Provide rich context to AI coding assistants
• Track why certain approaches failed
• Maintain institutional knowledge across AI sessions
• Export scoped documentation for specific tasks

For Teams

• Onboard new developers with comprehensive docs
• Document architectural decisions and trade-offs
• Track technical debt and future improvements
• Maintain living documentation that evolves with code

For Code Review

• Understand the "why" behind implementations
• Review documentation changes alongside code
• Ensure specs stay synchronized with reality
• Track decision history and lessons learned

IDE Integration

Hide .spec/ and .specs/ directories in your IDE. For VSCode, add to workspace settings:

{
  "files.exclude": {
    ".spec": true,
    ".specs": true
  }
}

Install Testing Branch From Test PyPI

pip install -i https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple/ --pre spec-ai

Contributing

We follow a vertical slice development philosophy - implementing features completely through implementation, testing, and typing before moving on. See CLAUDE.md for detailed development guidelines.

License

MIT License - see LICENSE for details.