Gearboy MCP — ユースケース, インストール & ライブデモ

なぜ使うのか

主な機能

Embedded MCP server with stdio and HTTP transport for AI-assisted debugging
Advanced debugger: JIT disassembler, CPU/memory breakpoints, trace logging
VRAM viewer with tile, sprite, and palette inspection
Supports MBC1-7, HuC-1/3, MMM01, Pocket Camera, TAMA5 cartridge types
LCD ghosting and dot matrix visual effects mimicking original hardware

ライブデモ

実際の動作

gearboy-2.replay ▶ 準備完了

0/0

インストール

クライアントを選択

~/Library/Application Support/Claude/claude_desktop_config.json · Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "gearboy-2": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/drhelius/Gearboy"
      ]
    }
  }
}

Claude Desktop → Settings → Developer → Edit Config を開く。保存後、アプリを再起動。

~/.cursor/mcp.json · .cursor/mcp.json

{
  "mcpServers": {
    "gearboy-2": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/drhelius/Gearboy"
      ]
    }
  }
}

Cursor は Claude Desktop と同じ mcpServers スキーマを使用。プロジェクト設定はグローバルより優先。

VS Code → Cline → MCP Servers → Edit

{
  "mcpServers": {
    "gearboy-2": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/drhelius/Gearboy"
      ]
    }
  }
}

Cline サイドバーの MCP Servers アイコンをクリックし、"Edit Configuration" を選択。

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "gearboy-2": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/drhelius/Gearboy"
      ]
    }
  }
}

Claude Desktop と同じ形式。Windsurf を再起動して反映。

~/.continue/config.json

{
  "mcpServers": [
    {
      "name": "gearboy-2",
      "command": "TODO",
      "args": [
        "See README: https://github.com/drhelius/Gearboy"
      ]
    }
  ]
}

Continue はマップではなくサーバーオブジェクトの配列を使用。

~/.config/zed/settings.json

{
  "context_servers": {
    "gearboy-2": {
      "command": {
        "path": "TODO",
        "args": [
          "See README: https://github.com/drhelius/Gearboy"
        ]
      }
    }
  }
}

context_servers に追加。保存時に Zed がホットリロード。

claude mcp add gearboy-2 -- TODO 'See README: https://github.com/drhelius/Gearboy'

ワンライナー。claude mcp list で確認、claude mcp remove で削除。

ユースケース

実用的な使い方： Gearboy

How to debug a Game Boy ROM with AI assistance using Gearboy

👤 Homebrew Game Boy developers and ROM hackers ⏱ ~30 min intermediate

使うタイミング： You're developing a Game Boy homebrew ROM and need to debug runtime issues.

前提条件

Gearboy built with MCP support — Build from source following the GitHub README
A Game Boy ROM file (.gb or .gbc) — Your own homebrew ROM or a ROM you legally own

フロー

Load ROM and connect

Connect to the Gearboy MCP server and load my ROM. Show me the current CPU state and disassembly at the program counter.✓ コピーしました

→ CPU registers, flags, and disassembled instructions at PC
Set a breakpoint and investigate

Set a breakpoint at address 0x0150 (after the header). Step through execution and explain what each instruction does.✓ コピーしました

→ Step-by-step execution with instruction explanations
Inspect memory

Show me the contents of WRAM from 0xC000 to 0xC0FF. Are there any recognizable data structures?✓ コピーしました

→ Memory dump with analysis of data patterns

結果： A clear understanding of how the ROM executes, with bugs identified and explained.

注意点

Breakpoints on frequently-hit addresses slow execution dramatically — Use conditional breakpoints or set them only when you're close to the bug

組み合わせ： filesystem

Learn Game Boy architecture interactively with AI and Gearboy

👤 Students learning retro console hardware and assembly ⏱ ~45 min intermediate

使うタイミング： You want to understand how the Game Boy CPU, memory, and graphics work hands-on.

前提条件

Gearboy with MCP server — Build from source
A simple test ROM — Use a homebrew test ROM or Blargg's test ROMs

フロー

Explore the memory map

Show me the Game Boy memory map. Read the ROM header at 0x0100-0x014F and explain each field.✓ コピーしました

→ Annotated header with title, cartridge type, ROM/RAM sizes
Watch VRAM in action

Step through the VBlank interrupt handler and explain how tiles are loaded into VRAM.✓ コピーしました

→ Step-by-step explanation of tile loading with VRAM state

結果： Hands-on understanding of Game Boy hardware through interactive exploration.

注意点

Assembly can be overwhelming for beginners — Start with simple test ROMs that exercise one hardware feature at a time

組み合わせ

他のMCPと組み合わせて10倍の力を

gearboy-2 + filesystem

Export memory dumps and debug logs for offline analysis

Dump the entire VRAM contents to a file and annotate the tile data layout.✓ コピーしました

ツール

このMCPが提供する機能

ツール	入力	呼び出すタイミング
pause/resume/step	none / step_count?	Control emulator execution
read_memory	address: int, size: int	Read emulator memory at any address
write_memory	address: int, data: bytes	Write to emulator memory
set_breakpoint	address: int, type?: str	Set a CPU or memory breakpoint
disassemble	address: int, count: int	Disassemble instructions at an address
get_cpu_state	none	Get current CPU registers and flags

コストと制限

運用コスト

APIクォータ: N/A — fully local
呼び出しあたりのトークン: 100–500 tokens per debug command
金額: Free and open source (MIT license)
ヒント: Use targeted memory reads instead of full dumps to keep token usage low.

セキュリティ

権限、シークレット、影響範囲

認証情報の保管： N/A

データ送信先： Fully local — no network calls

トラブルシューティング

よくあるエラーと対処法

MCP server not responding

Ensure Gearboy was built with MCP support enabled. Check that the server port (default 7777) is not in use.

確認： curl http://localhost:7777/health

ROM fails to load

Verify the ROM file is a valid .gb or .gbc file. Check the file isn't corrupted.

確認： Check the ROM header with a hex editor

Breakpoint never hits

Verify the address is in the execution path. Use the disassembler to check if code actually runs at that address.

確認： Disassemble around the target address

代替案

Gearboy 他との比較

代替案	代わりに使う場面	トレードオフ
Geargrafx	You want to debug PC Engine / TurboGrafx-16 ROMs instead of Game Boy	Different console, same MCP-enabled emulator approach by the same developer

その他

リソース

📖 GitHub の公式 README を読む

🐙 オープンな issue を見る

🔍 400以上のMCPサーバーとSkillsを見る