Lutin writes and runs Lua programs on the console, reads runtime errors, and edits the files in response to your requests.
Watch the presentation · MP4 Recorded DeepSeek responses replayed in melonDS, with file and runtime tools executing in the ROM.
2D recording · Software 3D recording
GPT 6 Luna generated both creations in live host sessions. These emulator recordings replay their final validation calls, then exercise real emulated input. See verification evidence.
Install · Configure · Controls · Architecture · Contribute
The DSi already has a stylus, two screens, physical buttons, Wi-Fi, and an SD card. Lutin uses that hardware for a coding agent: enter a request, run the resulting program, and ask for changes on the console.
The AI runs remotely through OpenCode Go. Your creations run locally in a bounded Lua sandbox. Saved programs also work offline. Lutin supports games, animations, drawing tools, and other interactive programs.
- Autonomous tools: read files, make version-checked edits, run programs, and inspect diagnostics.
- Creation tests: advance seeded frames with injected input and assert creation-defined state.
- Visual feedback: send PNG captures to image-capable models.
- Checkpoints: restore project source and assets after failed edits.
- Two-screen workflow: conversation above; keyboard, preview, or game controls below.
- Persistent sessions: create, switch, reset, and delete sessions stored on SD.
- Steer and Queue: redirect the current task or save requests for later.
- Local execution: draw shapes and text, read buttons and touch input, and inspect Lua errors.
- Generated assets: editable pixel sprites, animation frames, synthesized music, and sound effects. See asset APIs.
- Reusable APIs: tilemaps, camera movement, animation, modules, save data, and hardware-rendered 3D. See creation tools.
- Input capture: sample buttons at VBlank and retain short presses across a busy main-loop iteration.
- Visible progress: Wi-Fi state, transport stage, elapsed time, and received bytes.
- Reproducible builds: a pinned Nix environment, sanitizer tests, and emulator checks.
Dynamic projects and generated assets are available from v0.4.0.
| Component | Current support |
|---|---|
| Console | Nintendo DSi / DSi XL in DSi mode. User-tested on DSi XL. |
| Launcher | Console SD card, Unlaunch, and TWiLight Menu++. |
| Network | DSi Wi-Fi through DSWiFi, including DSi-mode WPA2 support. |
| AI service | OpenCode Go, with your own account and API key. |
| Models | GPT 6 Luna, GPT 5.6 Luna, Grok 4.7, DeepSeek V4.1 Flash. Availability depends on the service. |
| Build host | Linux x86-64 with Nix flakes enabled. |
| Emulator | melonDS DS-mode UI and runtime checks. Full DSi emulation requires your own console dumps. |
| Language | English interface and documentation. |
If your console does not have a homebrew launcher, follow DSi CFW Guide first. The detailed installation guide explains the optional setup kit and its files.
Use a FAT32 SD card and launch Lutin in DSi mode from the console's SD slot.
Download the SD ZIP from the latest release.
Extract it on your computer. It contains the ROM, CA bundle, configuration example, and starter program.
For an existing TWiLight Menu++ setup, copy the roms/ and lutin/ files to the matching SD directories.
Keep existing configuration and project files when updating.
The standalone .nds download is sufficient for a ROM-only update.
Release assets include SHA-256 checksums.
To build the full installation kit from source, run this from the repository root:
nix build .#installation-kit -o result-installationThe source-built kit uses these paths:
| Build output | SD destination |
|---|---|
result-installation/02-menu/roms/nds/lutin.nds |
/roms/nds/lutin.nds |
result-installation/02-menu/lutin/ca.pem |
/lutin/ca.pem |
result-installation/02-menu/lutin/config.json |
/lutin/config.json |
result-installation/02-menu/lutin/models.json |
/lutin/models.json |
result-installation/02-menu/lutin/projects/1/ |
/lutin/projects/1/ — optional starter program and assets |
Do not overwrite an existing project with the starter animation.
For an update, replace the ROM. Update the CA bundle when needed.
When upgrading from v0.4.0, also install models.json for the new SD catalog.
- Create an account and API key through OpenCode Go.
- Save the key as plain text in
/lutin/keys/opencode-goon the SD card. - Configure Wi-Fi in the DSi system settings.
- Set the correct console date and time for HTTPS certificate validation.
- Launch
/roms/nds/lutin.ndsfrom TWiLight Menu++ in DSi mode.
The key file contains only the key: no quotes, variable name, or Bearer prefix.
The application loads it from the SD card at runtime.
AI requests use your OpenCode Go allowance.
Try:
Create a small platformer. Use LEFT and RIGHT to move and A to jump. Start with a playable version, run it, and fix errors.
Select START → Play controls to send buttons and touch input to the running program. Preview displays the program without giving it your input. To try Lutin offline first, select START → Run program for the starter animation.
Edit /lutin/config.json, then restart Lutin:
{
"default_model": "opencode-go/deepseek-v4.1-flash",
"tool_details": false,
"startup_view": "sessions"
}| Key | Values | Default |
|---|---|---|
default_model |
Provider-qualified model ID, such as opencode-go/deepseek-v4.1-flash |
opencode-go/gpt-6-luna |
tool_details |
true or false |
false |
startup_view |
keyboard or sessions |
keyboard |
All keys are optional. A session's saved model takes priority over the default.
Unknown, repeated, or invalid keys reject the whole configuration and display a diagnostic.
Model IDs use provider/model in configuration and saved sessions.
The SD model catalog supports manual entries, reloading, and updates from the START command menu.
Each provider reads its own credential file from /lutin/keys/<provider-id>.
The bundled provider is opencode-go, with the four models listed above.
| Where | Control | Action |
|---|---|---|
| Anywhere | START | Open or close the menu. |
| Menu | Up/Down + A, or touch | Select an action. |
| Keyboard | Enter | Send the draft. |
| Outside gameplay | L / R | Select Queue / Steer. |
| Chat or preview | Up/Down | Scroll the conversation. |
| Sessions | X | Create a session. |
| Sessions | Up/Down + A | Open the selected session. |
| Sessions | Y / B | Reset / delete the current session, marked *. |
| Sessions | Right / Left | Next page / first page. |
| Queue | A / X / Y / Left | Resume / edit / move first / delete. |
Resetting a session clears its conversation, Queue, and tool journal. Project files remain on SD. Stop agent and Stop program are separate actions. See the user guide for the full behavior and Lua API.
flowchart TB
User[Buttons and stylus] --> Input[VBlank input capture]
Input --> UI[Native two-screen interface]
Input --> Runtime[Lua creation runtime]
UI --> Agent[Agent loop / Steer / Queue]
Agent --> Protocol[Responses and Chat Completions adapters]
Protocol --> Network[libcurl / Mbed TLS / DSWiFi]
Network <-->|HTTPS and SSE| Go[OpenCode Go]
Agent --> Tools[JSON file and runtime tools]
Agent --> CodeMode[Separate Lua Code Mode state]
CodeMode --> Tools
Tools --> Files[Version-checked project files]
Tools --> Runtime
Runtime --> Frame[RAM framebuffer]
Frame -->|VBlank copy| Screen[Lower screen]
Agent --> Sessions[Persistent sessions and tool journal]
Files --> SD[(SD card)]
Sessions --> SD
Config[Configuration and API key] --> Network
Config --> Agent
The native host owns input routing, networking, persistence, and display updates. Creation Lua and Code Mode use separate states with separate memory budgets. Tools run only after a complete model generation arrives. Completed tool calls are journaled to prevent automatic replay.
| Files | Responsibility |
|---|---|
source/main.c, source/chat.c |
Screens, keyboard, menus, and conversation display. |
source/input.h, source/platform_input.h |
Buffered input and hardware sampling. |
source/agent.c, source/tools.c |
Sessions, autonomous turns, and tool execution. |
source/network.c, source/protocol.c, source/sse.c |
Wi-Fi, HTTPS, API adapters, and streaming. |
source/runtime.c, source/sandbox.h |
Lua callbacks, drawing, input, and budgets. |
source/workspace.c, source/config.c |
SD storage and configuration. |
nix develop
make
prek run --all-files
nix flake check "path:$PWD" --no-write-lock-fileOr build only the ROM:
nix build .#rom -o result-romThe result is result-rom/lutin.nds.
Automated checks do not require credentials. They cover storage failures, sandbox limits, input buffering, stream parsing, configuration, sessions, and emulator behavior.
See verification evidence and contribution instructions.
- Creations use a 256 × 192 framebuffer, shapes, ASCII text, pixel sprites, and synthesized audio. See asset APIs.
- Lua creation memory is limited to 2 MiB. Code Mode uses at most 512 KiB.
- Project text files are limited to 32 KiB. Serialized sessions are limited to 192 KiB.
- Projects and sessions are created on demand and listed in bounded pages.
- Input capture retains a short press, but it does not make long native operations preemptible.
- Repeated presses of the same button during one blocked iteration merge into one event.
- User testing confirms operation on a DSi XL. New input changes still need physical-console validation.
Lutin is licensed under MIT. It builds on BlocksDS, libnds, DSWiFi, Lua, cJSON, libcurl, Mbed TLS, and the DS homebrew ecosystem. See third-party notices for dependencies and separately distributed installation tools.