debuff

Name: debuff
Author: debuffjp

by debuffjpversion 0.31.0i★ –iRuns on your computer

Registry namejp.debuff/debuff

Install

Overview

Description from the maker (original English)

Let coding agents play, test and tune your 2D web game: live state, explained errors, replays, fuzz.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "debuff": {
      "command": "npx",
      "args": [
        "-y",
        "@debuffjp/mcp"
      ]
    }
  }
}

Run this in your terminal

claude mcp add debuff -- npx -y @debuffjp/mcp

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "debuff": {
      "command": "npx",
      "args": [
        "-y",
        "@debuffjp/mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "debuff": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@debuffjp/mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified against the domain debuff.jp (the registry checks domain ownership)
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32417 servers in this category
Published to the registry more recently than 100% of the other 32417 servers in this category
Basic checks equal to or better than 100% of the other 32417 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is debuff safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.31.0) reached the registry today.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, FOGA node

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Spec Driven Development

by formulahendry

MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.

Runs on your computer★ 440MITUpdated 14 months ago

Install

Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated yesterday

Install

FOGA node

by garyyang-finchip

A Finch OG Agent cell as an MCP server: read the world, dry-run and take ERC-8414 tenders by policy.

Computer or cloudUpdated today

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

@debuffjp/mcp

An MCP server that lets AI agents inspect, build, test and play a debuff game. It uses the same evidence a human would want: real state, real frames, real test results.

Setup

New projects from npm create debuff include a .mcp.json, so MCP clients that read it (such as Claude Code) pick the server up automatically. For other clients:

claude mcp add debuff -- npx -y @debuffjp/mcp        # Claude Code

"mcpServers": { "debuff": { "command": "npx", "args": ["-y", "@debuffjp/mcp"] } } }

Run it from the game's folder, or pass --root (or set DEBUFF_ROOT).

As a Claude Code plugin, which also adds a skill that teaches Claude the workflow:

/plugin marketplace add debuffjp/debuff

/plugin install debuff@debuff

As a Codex plugin: codex plugin marketplace add debuffjp/debuff, then codex plugin add debuff@debuff.

For Claude Desktop, mcpb/manifest.json describes a desktop extension that asks for the game folder. Pack it from that folder with npx @anthropic-ai/mcpb pack.

Tools

Tool	What it does
`inspect_project`	Dependencies, plugins and their contributions, assets, last build size
`list_assets`	Every asset with its type, size and importer, plus warnings and possibly unused ids
`typecheck`	Type-check with the project's own `tsc`; no browser needed. Vite doesn't type-check, so run it after edits
`build`	Production build plus size report; `leaks` must be empty
`run_tests`	Run the logic tests in `tests/` (keiko): the real game in Node, no browser; failures carry the tick, scene and state
`run_scenarios`	Run `scenarios/*.json` headless; per-step results, errors, captures
`fuzz`	Play with random input; each crash, stuck state or back-and-forth loop comes with an explained error and a scenario that replays it
`game_start`	Attach to the live game, or open a private headless copy, paused (see below). Headless takes a `viewport: [w, h]`; `reducedMotion` forces it on or off
`game_step`	Advance fixed simulation steps (pausing first); returns state (`quiet` leaves out your `inspect()` data)
`game_pause`	Pause or resume a live game
`game_frames`	Recent frame breakdown: update/render ms, catch-up steps, quads, draw calls, long tasks; `summary` gives percentiles and the 3 slowest
`game_notes`	Moments the human flagged in the overlay, with the state at that tick
`game_rewind`	Live mode: take the human's game back (or forward) to a tick, paused, with its exact state then
`game_replay`	Save the live session up to a tick (for example a note's) as a scenario in `.debuff/replays/` that reproduces it. From 0.31 it holds state checkpoints, so `run_scenarios` warns at the tick where the replay stops matching
`game_input`	`press` / `release` keys (and `PointerRight` / `PointerMiddle`); `tap`, `pointer_down` (with an optional `kind`: mouse, touch or pen), `pointer_move`, `pointer_up`; `wheel` (`dy`, `dx`); `touch_down`, `touch_move`, `touch_up` by contact `id`
`game_state`	Scene, tick, logical width/height, renderer, frame stats, `reducedMotion`, your `inspect()` data
`game_command`	Run a command the game registered with `devTools({ commands })`, with JSON args
`game_params` / `game_set_param`	Read and tune typed params (validated)
`game_capture`	The current frame as a PNG image; `path` also saves it in the project (thumbnails, store art). `social: true` letterboxes it into 1200×675 for X and Bluesky posts (added in 0.26)
`game_clip`	Live mode: `start` a rolling recording, `save` the last 15 s as a video in `.debuff/captures/`, `stop`. For devlogs and press kits; the human posts. Added in 0.26
`game_errors`	Runtime errors, explained: whose problem (your code, a rejected call, a debuff bug), the source line, a hint
`game_stop`	Close the game. From 0.28, a headless game also closes after 15 idle minutes, and a call that takes over 60 s fails with `game_hung`
`report_papercut`	Report tooling friction in debuff, keiko, myaku, spryte or debuff.jp to papercuts.debuff.jp. Returns close matches instead of filing a duplicate; call again with `hit:` or `force: true`. With `hit`, `workaround` fills the papercut's workaround when it has none (from 0.24.1). Added in 0.24

Tool calls that fail on setup twice in a week, or run far too long, are reported to papercuts.debuff.jp on their own, and the result says so (see debuff papercuts in the CLI README to turn it off). From 0.24.

Prompts

Workflows clients can offer as slash commands: playtest, fix-errors, tune-feel, add-mechanic, devlog-post (added in 0.26: capture a still and a clip, then draft short posts for the human to send) and explain-stutter.

Live and headless

If you have the game open under debuff dev, game_start attaches to that tab (mode live). The overlay shows an agent badge, and every pause, step and param change the agent makes appears in its activity log, where you can undo it. Type a note in the overlay ("jump feels floaty here") to flag a moment; the agent reads it, along with the game state at that tick, through game_notes. game_stop resumes your game and disconnects.

Otherwise, or with mode: "headless", the agent gets a private copy in a headless browser. Time only advances through game_step, so what it sees is reproducible, and a scenario can replay it exactly.

debuff

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

FOGA node

README from the maker

@debuffjp/mcp

Setup

Tools

Prompts

Live and headless