legacy-modernizer

legacy-modernizer is an agent for Claude Code from alexmmatos/essentials-claude-code. It costs 30 tokens per session (1,327 once invoked), scanned A, original, no licence file.

A guide for updating old software systems in small, controlled steps. It focuses on reducing technical debt—the cost of outdated or difficult-to-change code—without interrupting the business.

In plain words
What is it for?
Use it to plan incremental migrations, reduce technical debt, and identify ways to protect business continuity during modernization.
Why use it?
It helps teams change legacy systems while limiting migration risks and keeping existing operations running.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

Part of the essentials-claude-code plugin — 3 skills, 3 commands, 156 agents, 1 hook shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/alexmmatos/essentials-claude-code/legacy-modernizer
Clone the repo
git clone --depth 1 https://github.com/alexmmatos/essentials-claude-code

Made for: Claude Code.

Or install essentials-claude-code, the plugin that ships this one along with the rest of its 3 skills, 3 commands, 156 agents, 1 hook.

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.

agentmods badge for legacy-modernizer

README.md
[![agentmods](https://agentmods.dev/badge/agents/alexmmatos/essentials-claude-code/legacy-modernizer.svg)](https://agentmods.dev/agents/alexmmatos/essentials-claude-code/legacy-modernizer)
Your own site
<a href="https://agentmods.dev/agents/alexmmatos/essentials-claude-code/legacy-modernizer"><img src="https://agentmods.dev/badge/agents/alexmmatos/essentials-claude-code/legacy-modernizer.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,327 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00030 $0.01327
Opus 5 $0.00015 $0.00664
Sonnet 5 $0.00006 $0.00265
Haiku 4.5 $0.00003 $0.00133

Measured 3d ago against content hash 3ef099720abd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

legacy-modernizer 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 3d 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/agents/legacy-modernizer.md · 286 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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.

  1. 3d ago First seen · 286 lines · 30 tokens per session scan A 3ef099720abd

Subscribe to this mod's changes

legacy-modernizer is an agent published in the GitHub repository alexmmatos/essentials-claude-code (1 stars, last pushed 2mo ago), with no licence file. It adds 30 tokens to every session and 1,327 once invoked, about $0.0002 per session on Opus 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 2026-09-03.

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