GitHub - mpfaffenberger/code_puppy: Agentic AI for writing code

Overview

This project was coded angrily in reaction to Windsurf and Cursor removing access to models and raising prices.

You could also run 50 code puppies at once if you were insane enough.

Would you rather plow a field with one ox or 1024 puppies? - If you pick the ox, better slam that back button in your browser.

Code Puppy is an AI-powered code generation agent, designed to understand programming tasks, generate high-quality code, and explain its reasoning similar to tools like Windsurf and Cursor.

Quick start

Installation

UV (Recommended)

macOS / Linux

# Install UV if you don't have it
curl -LsSf https://astral.sh/uv/install.sh | sh

# Set UV to always use managed Python (one-time setup)
echo 'export UV_MANAGED_PYTHON=1' >> ~/.zshrc  # or ~/.bashrc
source ~/.zshrc  # or ~/.bashrc

# Install and run code-puppy
uvx code-puppy -i

Windows

On Windows, we recommend installing code-puppy as a global tool for the best experience with keyboard shortcuts (Ctrl+C/Ctrl+X cancellation):

# Install UV if you don't have it (run in PowerShell as Admin)
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

# Install code-puppy as a global tool
uv tool install code-puppy

# Run code-puppy
code-puppy -i

Why uv tool install on Windows? Running with uvx creates an extra process layer that can interfere with keyboard signal handling (Ctrl+C, Ctrl+X). Installing as a tool runs code-puppy directly for reliable cancellation.

Upgrading

# Upgrade code-puppy to the latest version
uv tool upgrade code-puppy

# Or upgrade all installed tools
uv tool upgrade --all

UV will automatically download the latest compatible Python version (3.11+) if your system doesn't have one.

pip (Alternative)

Note: pip installation requires your system Python to be 3.11 or newer.

Permanent Python Management

To make UV always use managed Python versions (recommended):

# Set environment variable permanently
echo 'export UV_MANAGED_PYTHON=1' >> ~/.zshrc  # or ~/.bashrc
source ~/.zshrc  # or ~/.bashrc

# Now all UV commands will prefer managed Python installations
uvx code-puppy  # No need for --managed-python flag anymore

Verifying Python Version

# Check which Python UV will use
uv python find

# Or check the current project's Python
uv run python --version

Usage

Custom Commands

Create markdown files in .claude/commands/, .github/prompts/, or .agents/commands/ to define custom slash commands. The filename becomes the command name and the content runs as a prompt.

# Create a custom command
echo "# Code Review

Please review this code for security issues." > .claude/commands/review.md

# Use it in Code Puppy
/review with focus on authentication

Adding Models from models.dev 🆕

While there are several models configured right out of the box from providers like Synthetic, Cerebras, OpenAI, Google, and Anthropic, Code Puppy integrates with models.dev to let you browse and add models from 65+ providers with a single command:

This opens an interactive TUI where you can:

• Browse providers - See all available AI providers (OpenAI, Anthropic, Groq, Mistral, xAI, Cohere, Perplexity, DeepInfra, and many more)
• Preview model details - View capabilities, pricing, context length, and features
• One-click add - Automatically configures the model with correct endpoints and API keys

Live API with Offline Fallback

The /add_model command fetches the latest model data from models.dev in real-time. If the API is unavailable, it falls back to a bundled database:

📡 Fetched latest models from models.dev     # Live API
📦 Using bundled models database              # Offline fallback

Supported Providers

Code Puppy integrates with https://models.dev giving you access to 65 providers and >1000 different model offerings.

There are 39+ additional providers that already have OpenAI-compatible APIs configured in models.dev!

These providers are automatically configured with correct OpenAI-compatible endpoints, but have not been tested thoroughly:

Smart Warnings

• ⚠️ Unsupported Providers - Providers like Amazon Bedrock and Google Vertex that require special authentication are clearly marked
• ⚠️ No Tool Calling - Models without tool calling support show a big warning since they can't use Code Puppy's file/shell tools

Durable Execution

Code Puppy now supports DBOS durable execution.

When enabled, every agent is automatically wrapped as a DBOSAgent, checkpointing key interactions (including agent inputs, LLM responses, MCP calls, and tool calls) in a database for durability and recovery.

You can toggle DBOS via either of these options:

• CLI config (persists): /set enable_dbos true (or false to disable)

Config takes precedence if set; otherwise the environment variable is used.

Configuration

The following environment variables control DBOS behavior:

• DBOS_CONDUCTOR_KEY: If set, Code Puppy connects to the DBOS Management Console. Make sure you first register an app named dbos-code-puppy on the console to generate a Conductor key. Default: None.
• DBOS_LOG_LEVEL: Logging verbosity: CRITICAL, ERROR, WARNING, INFO, or DEBUG. Default: ERROR.
• DBOS_SYSTEM_DATABASE_URL: Database URL used by DBOS. Can point to a local SQLite file or a Postgres instance. Example: postgresql://postgres:dbos@localhost:5432/postgres. Default: dbos_store.sqlite file in the config directory.
• DBOS_APP_VERSION: If set, Code Puppy uses it as the DBOS application version and automatically tries to recover pending workflows for this version. Default: Code Puppy version + Unix timestamp in millisecond (disable automatic recovery).

Requirements

• Python 3.11+
• OpenAI API key (for GPT models)
• Gemini API key (for Google's Gemini models)
• Cerebras API key (for Cerebras models)
• Anthropic key (for Claude models)
• Ollama endpoint available

Agent Rules

We support AGENT.md files for defining coding standards and styles that your code should comply with. These rules can cover various aspects such as formatting, naming conventions, and even design guidelines.

For examples and more information about agent rules, visit https://agent.md

Using MCP Servers for External Tools

Use the /mcp command to manage MCP (list, start, stop, status, etc.)

Watch this video for examples! https://www.youtube.com/watch?v=1t1zEetOqlo

Round Robin Model Distribution

Code Puppy supports Round Robin model distribution to help you overcome rate limits and distribute load across multiple AI models. This feature automatically cycles through configured models with each request, maximizing your API usage while staying within rate limits.

Configuration

Add a round-robin model configuration to your ~/.code_puppy/extra_models.json file:

export CEREBRAS_API_KEY1=csk-...
export CEREBRAS_API_KEY2=csk-...
export CEREBRAS_API_KEY3=csk-...

{
  "qwen1": {
    "type": "cerebras",
    "name": "qwen-3-coder-480b",
    "custom_endpoint": {
      "url": "https://api.cerebras.ai/v1",
      "api_key": "$CEREBRAS_API_KEY1"
    },
    "context_length": 131072
  },
  "qwen2": {
    "type": "cerebras",
    "name": "qwen-3-coder-480b",
    "custom_endpoint": {
      "url": "https://api.cerebras.ai/v1",
      "api_key": "$CEREBRAS_API_KEY2"
    },
    "context_length": 131072
  },
  "qwen3": {
    "type": "cerebras",
    "name": "qwen-3-coder-480b",
    "custom_endpoint": {
      "url": "https://api.cerebras.ai/v1",
      "api_key": "$CEREBRAS_API_KEY3"
    },
    "context_length": 131072
  },
  "cerebras_round_robin": {
    "type": "round_robin",
    "models": ["qwen1", "qwen2", "qwen3"],
    "rotate_every": 5
  }
}

Then just use /model and tab to select your round-robin model!

The rotate_every parameter controls how many requests are made to each model before rotating to the next one. In this example, the round-robin model will use each Qwen model for 5 consecutive requests before moving to the next model in the sequence.

Create your own Agent!!!

Code Puppy features a flexible agent system that allows you to work with specialized AI assistants tailored for different coding tasks. The system supports both built-in Python agents and custom JSON agents that you can create yourself.

Quick Start

Check Current Agent

Shows current active agent and all available agents

Switch Agent

Switches to the specified agent

Create New Agent

Switches to the Agent Creator for building custom agents

Truncate Message History

Truncates the message history to keep only the N most recent messages while protecting the first (system) message. For example:

Would keep the system message plus the 19 most recent messages, removing older ones from the history.

This is useful for managing context length when you have a long conversation history but only need the most recent interactions.

Available Agents

Code-Puppy 🐶 (Default)

• Name: code-puppy
• Specialty: General-purpose coding assistant
• Personality: Playful, sarcastic, pedantic about code quality
• Tools: Full access to all tools
• Best for: All coding tasks, file management, execution
• Principles: Clean, concise code following YAGNI, SRP, DRY principles
• File limit: Max 600 lines per file (enforced!)

Agent Creator 🏗️

• Name: agent-creator
• Specialty: Creating custom JSON agent configurations
• Tools: File operations, reasoning
• Best for: Building new specialized agents
• Features: Schema validation, guided creation process

Agent Types

Python Agents

Built-in agents implemented in Python with full system integration:

• Discovered automatically from code_puppy/agents/ directory
• Inherit from BaseAgent class
• Full access to system internals
• Examples: code-puppy, agent-creator

JSON Agents

User-created agents defined in JSON files:

• Stored in user's agents directory
• Easy to create, share, and modify
• Schema-validated configuration
• Custom system prompts and tool access

Creating Custom JSON Agents

Using Agent Creator (Recommended)

1. Switch to Agent Creator:

2. Request agent creation:

   I want to create a Python tutor agent
   

3. Follow guided process to define:

   • Name and description
   • Available tools
   • System prompt and behavior
   • Custom settings

4. Test your new agent:

   /agent your-new-agent-name

Manual JSON Creation

Create JSON files in your agents directory following this schema:

{
  "name": "agent-name",              // REQUIRED: Unique identifier (kebab-case)
  "display_name": "Agent Name 🤖",   // OPTIONAL: Pretty name with emoji
  "description": "What this agent does", // REQUIRED: Clear description
  "system_prompt": "Instructions...",    // REQUIRED: Agent instructions
  "tools": ["tool1", "tool2"],        // REQUIRED: Array of tool names
  "user_prompt": "How can I help?",     // OPTIONAL: Custom greeting
  "tools_config": {                    // OPTIONAL: Tool configuration
    "timeout": 60
  }
}

Required Fields

• name: Unique identifier (kebab-case, no spaces)
• description: What the agent does
• system_prompt: Agent instructions (string or array)
• tools: Array of available tool names

Optional Fields

• display_name: Pretty display name (defaults to title-cased name + 🤖)
• user_prompt: Custom user greeting
• tools_config: Tool configuration object

Available Tools

Agents can access these tools based on their configuration:

• list_files: Directory and file listing
• read_file: File content reading
• grep: Text search across files
• edit_file: File editing and creation
• delete_file: File deletion
• agent_run_shell_command: Shell command execution
• agent_share_your_reasoning: Share reasoning with user

Tool Access Examples

• Read-only agent: ["list_files", "read_file", "grep"]
• File editor agent: ["list_files", "read_file", "edit_file"]
• Full access agent: All tools (like Code-Puppy)

System Prompt Formats

String Format

{
  "system_prompt": "You are a helpful coding assistant that specializes in Python development."
}

Array Format (Recommended)

{
  "system_prompt": [
    "You are a helpful coding assistant.",
    "You specialize in Python development.",
    "Always provide clear explanations.",
    "Include practical examples in your responses."
  ]
}

Example JSON Agents

Python Tutor

{
  "name": "python-tutor",
  "display_name": "Python Tutor 🐍",
  "description": "Teaches Python programming concepts with examples",
  "system_prompt": [
    "You are a patient Python programming tutor.",
    "You explain concepts clearly with practical examples.",
    "You help beginners learn Python step by step.",
    "Always encourage learning and provide constructive feedback."
  ],
  "tools": ["read_file", "edit_file", "agent_share_your_reasoning"],
  "user_prompt": "What Python concept would you like to learn today?"
}

Code Reviewer

{
  "name": "code-reviewer",
  "display_name": "Code Reviewer 🔍",
  "description": "Reviews code for best practices, bugs, and improvements",
  "system_prompt": [
    "You are a senior software engineer doing code reviews.",
    "You focus on code quality, security, and maintainability.",
    "You provide constructive feedback with specific suggestions.",
    "You follow language-specific best practices and conventions."
  ],
  "tools": ["list_files", "read_file", "grep", "agent_share_your_reasoning"],
  "user_prompt": "Which code would you like me to review?"
}

DevOps Helper

{
  "name": "devops-helper",
  "display_name": "DevOps Helper ⚙️",
  "description": "Helps with Docker, CI/CD, and deployment tasks",
  "system_prompt": [
    "You are a DevOps engineer specialized in containerization and CI/CD.",
    "You help with Docker, Kubernetes, GitHub Actions, and deployment.",
    "You provide practical, production-ready solutions.",
    "You always consider security and best practices."
  ],
  "tools": [
    "list_files",
    "read_file",
    "edit_file",
    "agent_run_shell_command",
    "agent_share_your_reasoning"
  ],
  "user_prompt": "What DevOps task can I help you with today?"
}

File Locations

JSON Agents Directory

• All platforms: ~/.code_puppy/agents/

Python Agents Directory

• Built-in: code_puppy/agents/ (in package)

Best Practices

Naming

• Use kebab-case (hyphens, not spaces)
• Be descriptive: "python-tutor" not "tutor"
• Avoid special characters

System Prompts

• Be specific about the agent's role
• Include personality traits
• Specify output format preferences
• Use array format for multi-line prompts

Tool Selection

• Only include tools the agent actually needs
• Most agents need agent_share_your_reasoning
• File manipulation agents need read_file, edit_file
• Research agents need grep, list_files

Display Names

• Include relevant emoji for personality
• Make it friendly and recognizable
• Keep it concise

System Architecture

Agent Discovery

The system automatically discovers agents by:

1. Python Agents: Scanning code_puppy/agents/ for classes inheriting from BaseAgent
2. JSON Agents: Scanning user's agents directory for *-agent.json files
3. Instantiating and registering discovered agents

JSONAgent Implementation

JSON agents are powered by the JSONAgent class (code_puppy/agents/json_agent.py):

• Inherits from BaseAgent for full system integration
• Loads configuration from JSON files with robust validation
• Supports all BaseAgent features (tools, prompts, settings)
• Cross-platform user directory support
• Built-in error handling and schema validation

BaseAgent Interface

Both Python and JSON agents implement this interface:

• name: Unique identifier
• display_name: Human-readable name with emoji
• description: Brief description of purpose
• get_system_prompt(): Returns agent-specific system prompt
• get_available_tools(): Returns list of tool names

Agent Manager Integration

The agent_manager.py provides:

• Unified registry for both Python and JSON agents
• Seamless switching between agent types
• Configuration persistence across sessions
• Automatic caching for performance

System Integration

• Command Interface: /agent command works with all agent types
• Tool Filtering: Dynamic tool access control per agent
• Main Agent System: Loads and manages both agent types
• Cross-Platform: Consistent behavior across all platforms

Adding Python Agents

To create a new Python agent:

1. Create file in code_puppy/agents/ (e.g., my_agent.py)
2. Implement class inheriting from BaseAgent
3. Define required properties and methods
4. Agent will be automatically discovered

Example implementation:

from .base_agent import BaseAgent

class MyCustomAgent(BaseAgent):
    @property
    def name(self) -> str:
        return "my-agent"

    @property
    def display_name(self) -> str:
        return "My Custom Agent ✨"

    @property
    def description(self) -> str:
        return "A custom agent for specialized tasks"

    def get_system_prompt(self) -> str:
        return "Your custom system prompt here..."

    def get_available_tools(self) -> list[str]:
        return [
            "list_files",
            "read_file",
            "grep",
            "edit_file",
            "delete_file",
            "agent_run_shell_command",
            "agent_share_your_reasoning"
        ]

Troubleshooting

Agent Not Found

• Ensure JSON file is in correct directory
• Check JSON syntax is valid
• Restart Code Puppy or clear agent cache
• Verify filename ends with -agent.json

Validation Errors

• Use Agent Creator for guided validation
• Check all required fields are present
• Verify tool names are correct
• Ensure name uses kebab-case

Permission Issues

• Make sure agents directory is writable
• Check file permissions on JSON files
• Verify directory path exists

Advanced Features

Tool Configuration

{
  "tools_config": {
    "timeout": 120,
    "max_retries": 3
  }
}

Multi-line System Prompts

{
  "system_prompt": [
    "Line 1 of instructions",
    "Line 2 of instructions",
    "Line 3 of instructions"
  ]
}

Future Extensibility

The agent system supports future expansion:

• Specialized Agents: Code reviewers, debuggers, architects
• Domain-Specific Agents: Web dev, data science, DevOps, mobile
• Personality Variations: Different communication styles
• Context-Aware Agents: Adapt based on project type
• Team Agents: Shared configurations for coding standards
• Plugin System: Community-contributed agents

Benefits of JSON Agents

1. Easy Customization: Create agents without Python knowledge
2. Team Sharing: JSON agents can be shared across teams
3. Rapid Prototyping: Quick agent creation for specific workflows
4. Version Control: JSON agents are git-friendly
5. Built-in Validation: Schema validation with helpful error messages
6. Cross-Platform: Works consistently across all platforms
7. Backward Compatible: Doesn't affect existing Python agents

Implementation Details

Files in System

• Core Implementation: code_puppy/agents/json_agent.py
• Agent Discovery: Integrated in code_puppy/agents/agent_manager.py
• Command Interface: Works through existing /agent command
• Testing: Comprehensive test suite in tests/test_json_agents.py

JSON Agent Loading Process

1. System scans ~/.code_puppy/agents/ for *-agent.json files
2. JSONAgent class loads and validates each JSON configuration
3. Agents are registered in unified agent registry
4. Users can switch to JSON agents via /agent <name> command
5. Tool access and system prompts work identically to Python agents

Error Handling

• Invalid JSON syntax: Clear error messages with line numbers
• Missing required fields: Specific field validation errors
• Invalid tool names: Warning with list of available tools
• File permission issues: Helpful troubleshooting guidance

Future Possibilities

• Agent Templates: Pre-built JSON agents for common tasks
• Visual Editor: GUI for creating JSON agents
• Hot Reloading: Update agents without restart
• Agent Marketplace: Share and discover community agents
• Enhanced Validation: More sophisticated schema validation
• Team Agents: Shared configurations for coding standards

Contributing

Sharing JSON Agents

1. Create and test your agent thoroughly
2. Ensure it follows best practices
3. Submit a pull request with agent JSON
4. Include documentation and examples
5. Test across different platforms

Python Agent Contributions

1. Follow existing code style
2. Include comprehensive tests
3. Document the agent's purpose and usage
4. Submit pull request for review
5. Ensure backward compatibility

Agent Templates

Consider contributing agent templates for:

• Code reviewers and auditors
• Language-specific tutors
• DevOps and deployment helpers
• Documentation writers
• Testing specialists

Code Puppy Privacy Commitment

Zero-compromise privacy policy. Always.

Unlike other Agentic Coding software, there is no corporate or investor backing for this project, which means zero pressure to compromise our principles for profit. This isn't just a nice-to-have feature – it's fundamental to the project's DNA.

What Code Puppy absolutely does not collect:

• ❌ Zero telemetry – no usage analytics, crash reports, or behavioral tracking
• ❌ Zero prompt logging – your code, conversations, or project details are never stored
• ❌ Zero behavioral profiling – we don't track what you build, how you code, or when you use the tool
• ❌ Zero third-party data sharing – your information is never sold, traded, or given away

What data flows where:

• LLM Provider Communication: Your prompts are sent directly to whichever LLM provider you've configured (OpenAI, Anthropic, local models, etc.) – this is unavoidable for AI functionality
• Complete Local Option: Run your own VLLM/SGLang/Llama.cpp server locally → zero data leaves your network. Configure this with ~/.code_puppy/extra_models.json
• Direct Developer Contact: All feature requests, bug reports, and discussions happen directly with me – no middleman analytics platforms or customer data harvesting tools

Our privacy-first architecture:

Code Puppy is designed with privacy-by-design principles. Every feature has been evaluated through a privacy lens, and every integration respects user data sovereignty. When you use Code Puppy, you're not the product – you're just a developer getting things done.

This commitment is enforceable because it's structurally impossible to violate it. No external pressures, no investor demands, no quarterly earnings targets to hit. Just solid code that respects your privacy.

License

This project is licensed under the MIT License - see the LICENSE file for details.