Dirty-Room Design Agent Skill

Lift-and-shift port of a repository, library, API, protocol, or other software artifact to a different language, runtime, or platform…

Context cost
6.8k tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 27.4 kBtext throughout, nothing executable
Licence
not declarednone named by its author
Last change
—no release on file
Servers it uses
Noneruns standalone

What it does

Lift-and-shift port of a repository, library, API, protocol, or other software artifact to a different language, runtime, or platform, with the original source available as a reference. This skill SHOULD be used when the user says "port from X to Y", "lift and shift", "rewrite in Go", "rewrite in Rust", "translate this codebase", "convert to TypeScript", "language migration", "rewrite in another language", "carry over the algorithms", "borrow techniques from", "dirty room", "dirty-room design", "sc-dirty-room", or wants to reimplement an existing artifact while studying its internals to…

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

developer tools

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md27.4 kB · preview
--- name: sc-dirty-room argument-hint: "[target: repo URL, local path, or artifact name] [optional: target language or scope]" ---
17# Dirty-Room Design
18
19This is a bastardization of the technique used by Compaq 1982 to clone the IBM PC BIOS.
20
21A structured approach to porting a software artifact to a different language or platform while consulting its internals. A **reading agent** examines the original and produces discovery, fixtures, and a translation brief — notes on which algorithms, data structures, and idioms are worth carrying across the language boundary. The implementation agent receives all three artifacts and explicit permission to read the original source directly.
22
23The clean-room skill builds a wall between specification and implementation to preserve copyright independence; the dirty-room takes notes through the open window because the constraints here are technical, not legal. Use this when the goal is a faithful port rather than an independent reimplementation.
24
25## EXECUTION MODEL
26
27**Phases 0 through 6 run in sequence. The core phases (1-4) MUST NOT be skipped or reordered.**
28
29- Phase 0 establishes scope, target language, and pins the artifact version
30- Phase 1 (Read) examines the original via a Task() agent and produces discovery, fixtures, and a translation brief
31- Phase 2 (Refine) finalises the spec and translation brief for handoff
32- Phase 3 (Port) builds in a Task() agent that may consult the original directly
33- Phase 4 (Verify) confirms equivalence via spec compliance and fixture replay
34- Phases 5-6 present results and offer next steps
35
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md3,783 words
Files1
Licencenot declared
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈230
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
6,620
on trigger
The instruction body, read only when the skill fires.
3.4%
of a 200k window
Ten skills this size would take about 34% of the window before you open a file.
050k100k150k200k context window

6.8k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

1 file, 27.4 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md27.4 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file you can review in full before installing.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Dirty-Room Design · 6.8k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/dirty-room-design/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/dirty-room-design" ] && { [ ! -e .claude/skills/dirty-room-design ] || { mv .claude/skills/dirty-room-design "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/dirty-room-design" .claude/skills/ && echo "Installed .claude/skills/dirty-room-design"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add kylesnowschwartz/dirty-room-design

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/dirty-room-design/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/dirty-room-design/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/dirty-room-design" ] && { [ ! -e ~/.claude/skills/dirty-room-design ] || { mv ~/.claude/skills/dirty-room-design "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/dirty-room-design" ~/.claude/skills/ && echo "Installed ~/.claude/skills/dirty-room-design" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/dirty-room-design/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. It appears as sc-dirty-room in Gemini CLI, Codex, Copilot and Grok (its own name); Claude Code lists it by the folder name, dirty-room-design.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Versionnot versioned
Publishedno release date on file
PriceFree
Referencekylesnowschwartz/dirty-room-design

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

Reviews

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