modernization-planner

modernization-planner is an agent for coding agents from drvoss/harness-100-copilot. It costs 41 tokens per session (1,890 once invoked), scanned A, original, no licence file.

An agent for planning how to update a legacy system, meaning older software that still needs to be maintained. It creates migration phases, explains technology choices, and uses a gradual replacement approach called the strangler fig strategy.

In plain words
What is it for?
Use it to create a modernization roadmap, choose technologies, plan migration phases, and design a gradual replacement strategy for legacy software.
Why use it?
It turns a difficult full-system update into prioritised stages with reasons for the planned technology changes.

Agent

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/drvoss/harness-100-copilot/modernization-planner
Clone the repo
git clone --depth 1 https://github.com/drvoss/harness-100-copilot

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 modernization-planner

README.md
[![agentmods](https://agentmods.dev/badge/agents/drvoss/harness-100-copilot/modernization-planner.svg)](https://agentmods.dev/agents/drvoss/harness-100-copilot/modernization-planner)
Your own site
<a href="https://agentmods.dev/agents/drvoss/harness-100-copilot/modernization-planner"><img src="https://agentmods.dev/badge/agents/drvoss/harness-100-copilot/modernization-planner.svg" alt="Measured on agentmods" height="20"></a>
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,890 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 $0.00041 $0.01890
Opus 5 $0.00020 $0.00945
Sonnet 5 $0.00008 $0.00378
Haiku 4.5 $0.00004 $0.00189

Measured 4d ago against content hash 092e037d174b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

modernization-planner 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 4d 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.

harnesses/22-legacy-modernizer/agents/modernization-planner.md · 168 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

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. 4d ago First seen · 168 lines · 41 tokens per session scan A 092e037d174b

Subscribe to this mod's changes

modernization-planner is an agent published in the GitHub repository drvoss/harness-100-copilot (5 stars, last pushed 3mo ago), with no licence file. It adds 41 tokens to every session and 1,890 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 2026-08-31.