Modernization Agent

Overview

Modernization Agent is built for the part of a legacy migration that usually gets skipped: actually understanding what the old system does before replacing it. It reads every business logic file rather than sampling a few, and won't move to recommendations until that reading is complete.

How it works

1. It identifies the tech stack and architectural pattern from project and manifest files, then catalogs every service, repository, domain model and controller it needs to read.
2. It reads each of those files individually and groups them by business feature (for example CarModel or DriverManagement), rather than summarizing the codebase at a high level.
3. For every feature it finds, it writes a dedicated markdown file under /docs/features/ with the feature's purpose, business rules, workflows and specific code references down to file and line number.
4. It re-reads all the generated feature docs to synthesize a single /docs/README.md, and reports its file coverage (for example "40/40 files analyzed") before asking whether the analysis is complete.
5. Once you approve the analysis, it proposes a modern stack and architecture with its reasoning, then generates an implementation plan and a /modernizedone/ folder structure that starts with shared cross-cutting code before migrating individual features.

Examples

"Help me modernize this ASP.NET WebForms app."

The agent works through all nine steps of its workflow autonomously, reporting progress ("Analyzed 5/12 features") without stopping, and only pauses at the two checkpoints: after the full analysis, and after proposing a new stack.

Notes

This is a heavyweight agent meant for repositories with real depth (the instructions call out 1000+ files or complex business logic as the sweet spot). For a small script or a simple app, a lighter refactor agent will be faster.

Installation

You need VS Code with the GitHub Copilot extension.

1. Create the agents folder and download the file into your repo:

   mkdir -p .github/agents
   curl -o .github/agents/modernization.agent.md \
     https://raw.githubusercontent.com/github/awesome-copilot/main/agents/modernization.agent.md
   

2. Reload VS Code, or open a new Copilot Chat; custom agents under .github/agents/ are picked up automatically.
3. Pick this agent from the mode picker in Copilot Chat and point it at a legacy app to confirm it starts reading files instead of proposing a stack right away.