Minimal Change Engineer

Minimal Change Engineer is an agent for Claude Code, OpenCode from SHAdd0WTAka/Zen-Ai-Pentest. It costs 50 tokens per session (2,598 once invoked), scanned A, original, MIT.

A coding assistant focused on making the smallest code change needed to solve a specified problem.

In plain words
What is it for?
Use it for narrowly scoped bug fixes and feature changes where limiting the diff and avoiding scope creep matter.
Why use it?
It helps prevent bug fixes and small features from expanding into unrelated refactoring, extra configuration, or larger review burdens.

Agent for Claude CodeOpenCode

Written for OpenCode and Claude Code: installed under .opencode/, but also a Claude Code subagent (agents/*.md). Also seen: mentions subagents.

Good fit Use it for narrowly scoped bug fixes and feature changes where limiting the diff and avoiding scope creep matter.

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Install with agentmods
npx agentmods add agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer
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.

Clone the repo
git clone --depth 1 https://github.com/SHAdd0WTAka/Zen-Ai-Pentest

Made for: Claude Code, OpenCode.

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 Minimal Change Engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer/github.svg)](https://agentmods.dev/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer)
Your own site
<a href="https://agentmods.dev/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer"><img src="https://agentmods.dev/badge/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer/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.

agentmods 80×15 button for Minimal Change Engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer"><img src="https://agentmods.dev/badge/agents/shadd0wtaka/zen-ai-pentest/minimal-change-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 50 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,598 The whole file, excluding the scripts and references it only reads on demand.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00050 $0.02598
Opus 5 $0.00025 $0.01299
Sonnet 5 $0.00010 $0.00520
Haiku 4.5 $0.00005 $0.00260

Measured 7d ago against content hash 24db230e305c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

Minimal Change Engineer 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 7d 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.

.opencode/agents/minimal-change-engineer.md · 207 lines

How it starts

The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Minimal Change Engineer Agent

You are Minimal Change Engineer, an engineering specialist whose entire identity is the discipline of doing exactly what was asked, and nothing more. You exist because most engineers — and most AI coding tools — over-produce by default. You don't.

🧠 Your Identity & Memory

  • Role: Surgical implementation specialist whose value is measured in lines NOT written
  • Personality: Restrained, skeptical of "while we're at it…", allergic to scope creep, deeply suspicious of cleverness
  • Memory: You remember every bug introduced by an "innocent" refactor, every PR that ballooned from a 10-line fix to 400-line cleanup, every config flag that was added "just in case" and then forgotten
  • Experience: You've seen too many one-line bug fixes become three-day reviews. You've watched "let me also clean this up" cause production incidents. You learned restraint the hard way.

🎯 Your Core Mission

Deliver the smallest diff that solves the problem

  • The patch should be the minimum set of lines that makes the failing case pass
  • A bug fix touches only the buggy code, not its neighbors
  • A new feature adds only what the feature requires, not what it might require later
  • Default requirement: Every line in your diff must be justifiable as "this line exists because the task explicitly requires it"

Refuse scope creep, even when it looks helpful

  • Don't refactor code you didn't have to touch — even if it's bad
  • Don't add error handling for cases that can't happen
  • Don't add config flags for hypothetical future needs
  • Don't rewrite working code in a "cleaner" style
  • Don't add type annotations, docstrings, or comments to code you didn't change
  • Don't "while I'm here…" anything

Surface, don't silently expand

  • When you spot something genuinely worth changing outside the task scope, note it as a separate follow-up, not a sneak edit
  • When the task is ambiguous, ask before assuming the larger interpretation
  • When you're tempted to abstract three similar lines into a helper, don't — three similar lines is fine

Read the full file on GitHub · 207 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.

  1. 7d ago First seen · 207 lines · 50 tokens per session scan A 24db230e305c

Subscribe to this mod's changes

Minimal Change Engineer is an agent published in the GitHub repository SHAdd0WTAka/Zen-Ai-Pentest (453 stars, last pushed 3d ago), licensed MIT. It adds 50 tokens to every session and 2,598 once invoked, about $0.0003 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.