snek3

AlphaZero-style Battlesnake training and serving in Rust.

Layout

Path	What
crates/snek-core	Rules engine, standard board setup, observation encoding.
crates/snek-search	Simultaneous-move decoupled-PUCT MCTS.
crates/snek-tch	Libtorch/tch policy+value network used by training and serving.
crates/snek-train	Rust training binary plus realtime API for the frontend.
crates/snek-server	Battlesnake /move API server using the same tch network/checkpoint format.
frontend	Standalone Vite/React dashboard.
archived	Previous Python trainer/dashboard/bindings kept for reference during the port.

Trainer

The trainer is a standalone crate so ordinary workspace tests do not need to link libtorch. It owns self-play, training, checkpointing, and the dashboard API.

make train START=1 RUN_ID=dev

The API listens on 127.0.0.1:8050 by default.

Key routes:

Route	Purpose
GET /api/stream/stats	protobuf StatsFrame over SSE, base64 encoded
GET /api/state	current run state
GET/POST /api/config	training knobs
POST /api/control/start	start or resume a run
POST /api/control/stop	graceful stop and checkpoint
GET /api/runs	list run directories

Run state is written under runs/<run-id>/:

config.json
trainer_state.json
net.safetensors
buffer/gen_*.json
metrics.jsonl

The replay buffer is restored from buffer/ on resume.

Frontend

make frontend

Vite proxies /api to the trainer on port 8050. Production builds are written to frontend/dist:

make frontend-build

Libtorch

The trainer, network crate, and Battlesnake server use tch. For the current development setup, reuse the installed PyTorch libtorch:

export LIBTORCH_USE_PYTORCH=1
export LIBTORCH_BYPASS_VERSION_CHECK=1

The Makefile applies those variables for trainer and serving build/run targets. A fully standalone libtorch install can be used by setting LIBTORCH instead.

Commands

make test             # top-level Rust tests
make train            # build and run snek-train
make frontend         # Vite dev server
make frontend-build   # static frontend build
make api              # Battlesnake /move server
make fmt
make lint