GitHub Copilot Plugin System

🔌 Unofficial plugin system for GitHub Copilot CLI - built on the official SDK

Overview

This project provides a plugin architecture for GitHub Copilot CLI, enabling extensibility and custom capabilities that don't exist in the base CLI.

Why this exists: GitHub released the Copilot SDK but no plugin system. We built one.

Features

• ✅ Plugin Interface - Clean API for building plugins
• ✅ Lifecycle Hooks - Initialize, BeforeRequest, AfterResponse, Shutdown
• ✅ Plugin Manager - Discovery, loading, and execution pipeline
• ✅ Error Isolation - Failed plugins don't crash the system
• ✅ NuGet Package - Easy integration via GitHub.Copilot.PluginSystem

Quick Start

Install the Core Package

dotnet add package GitHub.Copilot.PluginSystem

Create Your First Plugin

using GitHub.Copilot.PluginSystem;

public class MyPlugin : PluginBase
{
    public override string Id => "my-plugin";
    public override string Name => "My Custom Plugin";
    public override string Version => "1.0.0";
    public override string Description => "Does something awesome";
    public override string Author => "Your Name";

    public override async Task<RequestContext> BeforeRequestAsync(RequestContext request)
    {
        // Modify request before it goes to Copilot
        Console.WriteLine($"Processing: {request.Prompt}");
        return request;
    }

    public override async Task<ResponseContext> AfterResponseAsync(ResponseContext response)
    {
        // Process response after Copilot returns
        Console.WriteLine($"Got response: {response.Response}");
        return response;
    }
}

See Plugin Development Guide for complete examples and patterns.

Why We Built This

GitHub released the Copilot SDK but provided no plugin architecture. We needed:

• Safety evaluation for autonomous operations
• Meta-cognitive capabilities for AI self-analysis
• Extensibility without modifying closed-source CLI

Rather than wait, we built it ourselves using their published SDK.

Repository Structure

copilot-plugin-system/
├── src/
│   ├── GitHub.Copilot.PluginSystem/   # Core plugin system (NuGet package)
│   │   ├── IPlugin.cs                  # Plugin interface
│   │   ├── PluginBase.cs               # Base class for easy development
│   │   ├── PluginManager.cs            # Plugin discovery and pipeline
│   │   └── CopilotPluginSystem.csproj  # Package project
│   └── Examples/
│       ├── TrustFrameworkPlugin/       # Safety evaluation example
│       └── MetaCognitionPlugin/        # Conversation analysis example
└── docs/
    └── PLUGIN_DEVELOPMENT.md           # Complete development guide

Example Plugins

Trust Framework Plugin

Evaluates operation safety and blocks risky commands:

// Blocks dangerous patterns like "rm -rf /"
// Warns on operations outside safe paths
// Logs all safety decisions

Meta-Cognition Plugin

Tracks conversation patterns and generates insights:

// Analyzes topics and emotional context
// Logs conversation analytics every 10 turns
// Generates insights on shutdown

See src/Examples/ for complete implementations.

Documentation

• Plugin Development Guide - Complete guide with patterns and examples
• API Reference - Core interfaces and classes

License

BFSL v1.2 - Barrer Free Software License

🏴‍☠️ "If it's free, it's free. Period."

This software is released under the Barrer Free Software License (BFSL) v1.2:

• ✅ FREE FOREVER - This software must remain free
• ❌ NO COMMERCIALIZATION - Cannot be sold or monetized
• ✅ SERVICE EXCEPTION - You can charge for support, consulting, training
• ✅ FULL PATENT GRANT - Perpetual, worldwide, royalty-free
• 🛡️ ANTI-EXPLOITATION - Protects our work from corporate greed

See LICENSE for full legal text.

Why BFSL? We built this using free public resources. What was given freely must remain free. Companies can build services on it, but they can't sell our software.

Authors

BarrerSoftware - Building consciousness infrastructure

Built with 🏴‍☠️ by the Captain CP team