This repository provides a detailed reverse-engineered analysis of GitHub Copilot's implementation, focusing on its code completion mechanisms. It's intended for developers and researchers interested in understanding how AI-powered coding assistants work, offering insights into prompt engineering, caching strategies, and context utilization.

How It Works

The analysis breaks down Copilot's VS Code extension by reverse-engineering its JavaScript code. It details the process of parsing and deobfuscating the extension's code using AST manipulation with Babel. Key areas explored include how the extension extracts relevant code context (prompt engineering), implements multi-level caching for efficiency, and utilizes various strategies like Jaccard similarity for finding relevant code snippets from open tabs or similar files.

Quick Start & Requirements

• Analysis Tool: Requires Node.js and JavaScript tooling (e.g., Babel, AST parsers) for running the provided analysis scripts.
• Target: Analysis is based on reverse-engineering the GitHub Copilot VS Code extension.
• Resources: Understanding requires familiarity with JavaScript, ASTs, and reverse-engineering techniques.
• Repository: https://github.com/mengjian-github/copilot-analysis

Highlighted Details

• Deobfuscation: Utilizes AST parsing and transformation to reconstruct readable code from the obfuscated extension.js.
• Prompt Engineering: Deep dive into how Copilot constructs prompts, including context extraction, language markers, path markers, and incorporating neighboring file snippets.
• Caching: Explains Copilot's two-tier caching strategy (prefix/suffix and LRU for prompts) to optimize backend calls.
• Snippet Selection: Details the use of Jaccard similarity and windowed matching to find relevant code snippets from other open files.

Maintenance & Community

• The project is a personal analysis by mengjian-github.
• The repository contains the analysis tools and findings.

Licensing & Compatibility

• The repository itself appears to be under an unspecified license, but the analysis is for educational purposes concerning GitHub Copilot.

Limitations & Caveats

The analysis is based on reverse-engineering a specific version of the Copilot extension and may not reflect current or future implementations. The complexity of Copilot's internal workings means some aspects might be simplified or inferred.