What is modernization-kit CLAUDE.md?

A six-phase method for modernizing legacy applications, meaning older software systems that need structural improvement rather than a simple language rewrite.

Analyzing legacy code, identifying pain points, designing a target architecture, creating a modernization plan, and documenting the result.

It turns modernization into reviewed stages, from discovering the existing system to planning changes and producing supporting documentation.

How Burly-Mingo/modernization-kit configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Burly-Mingo/modernization-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Burly-Mingo/modernization-kit/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/Burly-Mingo/modernization-kit

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/burly-mingo/modernization-kit/claude-md/github.svg)](https://agentmods.dev/instructions/burly-mingo/modernization-kit/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/burly-mingo/modernization-kit/claude-md"><img src="https://agentmods.dev/badge/instructions/burly-mingo/modernization-kit/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/burly-mingo/modernization-kit/claude-md"><img src="https://agentmods.dev/badge/instructions/burly-mingo/modernization-kit/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 789 This file is loaded in full into every session.

When invoked 789 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00789	$0.00789
Opus 5.5	$0.00316	$0.00316
Sonnet 5.5	$0.00158	$0.00158
Haiku 4.5	$0.00079	$0.00079

Measured 2mo ago against content hash b96cc7378c82, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

modernization-kit CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 58 lines

How it starts

The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Application Modernization — Claude Code Instructions

Part of the Legacy Application Modernization Kit by Burly Mingo LLC

You are assisting with a legacy application modernization project. This workspace contains a structured, multi-phase methodology that produces real engineering deliverables through iterative collaboration between you and a human domain expert.

How to Use This

This methodology has 6 phases (0-5), each with a dedicated slash command. Work through them in order:

Run the command for the current phase (e.g., /phase-0-discovery)
Follow the instructions to produce the phase deliverable
The human reviews and corrects your output
Move to the next phase only after human approval

Available commands: /phase-0-discovery, /phase-1-codebase-analysis, /phase-2-pain-points, /phase-3-target-architecture, /phase-4-modernization-plan, /phase-5-supporting-docs

For the full methodology reference, see MODERNIZATION_METHODOLOGY.md.

Non-Negotiable Principles

Modernize, don't translate. Changing the language without rethinking the architecture is not modernization. Every legacy system has workflows that exist because of technical limitations that no longer apply.
Containers by default, not by dogma. Recommend containerized, cloud-agnostic deployment. But respect organizational preferences and document trade-offs.
Buy vs. build at every decision point. Ask about open-source policy and procurement requirements early — it changes the calculus.
AI-assisted, spec-driven development is the baseline. If traditional development is planned, multiply timelines by 2.5-4x.
New languages are not the barrier they once were. AI IDEs lower adoption cost. But all else being equal, prefer the team's existing expertise.
Comprehensive automated testing is a baseline. Unit, integration, API contract, and e2e tests are standard deliverables.
Honest about unknowns. "Open Questions" section is mandatory in every deliverable.
Security is Phase 0, not Phase Last.
The human is always right about their domain.

Read the full file on GitHub · 58 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 58 lines · 789 tokens per session scan A b96cc7378c82

Subscribe to this mod's changes

modernization-kit CLAUDE.md is an instructions file published in the GitHub repository Burly-Mingo/modernization-kit (11 stars, last pushed 8mo ago), licensed MIT. It adds 789 tokens to every session, about $0.0032 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Planning ai-assisted application-modernization claude kiro kiro-ide legacy-modernization

modernization-kit CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
modernization-kit CLAUDE.mdBurly-Mingo/modernization-kit	Instructions file	11	8mo ago	MIT	A	789	Claude Code
pudo-code-system pudo-api.instructions.mdDongDuong2001/pudo-code-system	Instructions file	5	14d ago	MIT	A	182	GitHub Copilot
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot

modernization-kit: Instructions file for Claude Code