Initial project setup for OpenEnv Hackathon

Scaffolded OpenEnv 0.2.1 environment with FastAPI server, client,
training script (TRL GRPO + Unsloth), and Docker/HF Spaces deployment.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

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+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+*.egg-info/
+dist/
+build/
+*.egg
+
+# Virtual environments
+.venv/
+venv/
+env/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Environment
+.env
+.env.local
+
+# Jupyter
+.ipynb_checkpoints/
+
+# Docker
+*.log
+
+# uv
+uv.lock

README.md

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+# OpenEnv Hackathon Project
+
+Built for the [OpenEnv Hackathon](https://cerebralvalley.ai/e/openenv-hackathon-sf) (March 7-8, 2026)
+
+## Quick Start
+
+```bash
+# Setup
+python3.12 -m venv .venv
+source .venv/bin/activate
+pip install "openenv-core[core]>=0.2.1"
+
+# Run environment locally
+cd hackathon_env
+uvicorn server.app:app --reload --host 0.0.0.0 --port 8000
+```
+
+## Project Structure
+
+```
+openev/
+├── hackathon_env/           # OpenEnv environment
+│   ├── models.py            # Action/Observation data models
+│   ├── client.py            # Environment client
+│   ├── server/
+│   │   ├── hackathon_env_environment.py  # Core environment logic
+│   │   ├── app.py           # FastAPI server
+│   │   └── Dockerfile       # Container config
+│   ├── openenv.yaml         # OpenEnv spec
+│   └── pyproject.toml       # Dependencies
+├── train.py                 # Training script (TRL + GRPO)
+└── README.md
+```
+
+## Deployment
+
+### HuggingFace Spaces
+
+```bash
+# Build & push to HF Spaces
+cd hackathon_env
+openenv push --space <your-hf-username>/hackathon-env
+```
+
+### Local Docker
+
+```bash
+cd hackathon_env
+docker build -t hackathon-env:latest -f server/Dockerfile .
+docker run -p 8000:8000 hackathon-env:latest
+```
+
+## Training
+
+See `train.py` for the minimal training script using HF TRL's GRPOTrainer with OpenEnv integration.
+
+## Tech Stack
+
+- **OpenEnv** 0.2.1 - Environment framework
+- **HuggingFace TRL** - RL training (GRPO)
+- **Unsloth** - Fast fine-tuning (2x speed, 70% less VRAM)

hackathon_env/README.md

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+---
+title: Hackathon Env Environment Server
+emoji: 📻
+colorFrom: gray
+colorTo: blue
+sdk: docker
+pinned: false
+app_port: 8000
+base_path: /web
+tags:
+  - openenv
+---
+
+# Hackathon Env Environment
+
+A simple test environment that echoes back messages. Perfect for testing the env APIs as well as demonstrating environment usage patterns.
+
+## Quick Start
+
+The simplest way to use the Hackathon Env environment is through the `HackathonEnv` class:
+
+```python
+from hackathon_env import HackathonAction, HackathonEnv
+
+try:
+    # Create environment from Docker image
+    hackathon_envenv = HackathonEnv.from_docker_image("hackathon_env-env:latest")
+
+    # Reset
+    result = hackathon_envenv.reset()
+    print(f"Reset: {result.observation.echoed_message}")
+
+    # Send multiple messages
+    messages = ["Hello, World!", "Testing echo", "Final message"]
+
+    for msg in messages:
+        result = hackathon_envenv.step(HackathonAction(message=msg))
+        print(f"Sent: '{msg}'")
+        print(f"  → Echoed: '{result.observation.echoed_message}'")
+        print(f"  → Length: {result.observation.message_length}")
+        print(f"  → Reward: {result.reward}")
+
+finally:
+    # Always clean up
+    hackathon_envenv.close()
+```
+
+That's it! The `HackathonEnv.from_docker_image()` method handles:
+- Starting the Docker container
+- Waiting for the server to be ready
+- Connecting to the environment
+- Container cleanup when you call `close()`
+
+## Building the Docker Image
+
+Before using the environment, you need to build the Docker image:
+
+```bash
+# From project root
+docker build -t hackathon_env-env:latest -f server/Dockerfile .
+```
+
+## Deploying to Hugging Face Spaces
+
+You can easily deploy your OpenEnv environment to Hugging Face Spaces using the `openenv push` command:
+
+```bash
+# From the environment directory (where openenv.yaml is located)
+openenv push
+
+# Or specify options
+openenv push --namespace my-org --private
+```
+
+The `openenv push` command will:
+1. Validate that the directory is an OpenEnv environment (checks for `openenv.yaml`)
+2. Prepare a custom build for Hugging Face Docker space (enables web interface)
+3. Upload to Hugging Face (ensuring you're logged in)
+
+### Prerequisites
+
+- Authenticate with Hugging Face: The command will prompt for login if not already authenticated
+
+### Options
+
+- `--directory`, `-d`: Directory containing the OpenEnv environment (defaults to current directory)
+- `--repo-id`, `-r`: Repository ID in format 'username/repo-name' (defaults to 'username/env-name' from openenv.yaml)
+- `--base-image`, `-b`: Base Docker image to use (overrides Dockerfile FROM)
+- `--private`: Deploy the space as private (default: public)
+
+### Examples
+
+```bash
+# Push to your personal namespace (defaults to username/env-name from openenv.yaml)
+openenv push
+
+# Push to a specific repository
+openenv push --repo-id my-org/my-env
+
+# Push with a custom base image
+openenv push --base-image ghcr.io/meta-pytorch/openenv-base:latest
+
+# Push as a private space
+openenv push --private
+
+# Combine options
+openenv push --repo-id my-org/my-env --base-image custom-base:latest --private
+```
+
+After deployment, your space will be available at:
+`https://huggingface.co/spaces/<repo-id>`
+
+The deployed space includes:
+- **Web Interface** at `/web` - Interactive UI for exploring the environment
+- **API Documentation** at `/docs` - Full OpenAPI/Swagger interface
+- **Health Check** at `/health` - Container health monitoring
+- **WebSocket** at `/ws` - Persistent session endpoint for low-latency interactions
+
+## Environment Details
+
+### Action
+**HackathonAction**: Contains a single field
+- `message` (str) - The message to echo back
+
+### Observation
+**HackathonObservation**: Contains the echo response and metadata
+- `echoed_message` (str) - The message echoed back
+- `message_length` (int) - Length of the message
+- `reward` (float) - Reward based on message length (length × 0.1)
+- `done` (bool) - Always False for echo environment
+- `metadata` (dict) - Additional info like step count
+
+### Reward
+The reward is calculated as: `message_length × 0.1`
+- "Hi" → reward: 0.2
+- "Hello, World!" → reward: 1.3
+- Empty message → reward: 0.0
+
+## Advanced Usage
+
+### Connecting to an Existing Server
+
+If you already have a Hackathon Env environment server running, you can connect directly:
+
+```python
+from hackathon_env import HackathonEnv
+
+# Connect to existing server
+hackathon_envenv = HackathonEnv(base_url="<ENV_HTTP_URL_HERE>")
+
+# Use as normal
+result = hackathon_envenv.reset()
+result = hackathon_envenv.step(HackathonAction(message="Hello!"))
+```
+
+Note: When connecting to an existing server, `hackathon_envenv.close()` will NOT stop the server.
+
+### Using the Context Manager
+
+The client supports context manager usage for automatic connection management:
+
+```python
+from hackathon_env import HackathonAction, HackathonEnv
+
+# Connect with context manager (auto-connects and closes)
+with HackathonEnv(base_url="http://localhost:8000") as env:
+    result = env.reset()
+    print(f"Reset: {result.observation.echoed_message}")
+    # Multiple steps with low latency
+    for msg in ["Hello", "World", "!"]:
+        result = env.step(HackathonAction(message=msg))
+        print(f"Echoed: {result.observation.echoed_message}")
+```
+
+The client uses WebSocket connections for:
+- **Lower latency**: No HTTP connection overhead per request
+- **Persistent session**: Server maintains your environment state
+- **Efficient for episodes**: Better for many sequential steps
+
+### Concurrent WebSocket Sessions
+
+The server supports multiple concurrent WebSocket connections. To enable this,
+modify `server/app.py` to use factory mode:
+
+```python
+# In server/app.py - use factory mode for concurrent sessions
+app = create_app(
+    HackathonEnvironment,  # Pass class, not instance
+    HackathonAction,
+    HackathonObservation,
+    max_concurrent_envs=4,  # Allow 4 concurrent sessions
+)
+```
+
+Then multiple clients can connect simultaneously:
+
+```python
+from hackathon_env import HackathonAction, HackathonEnv
+from concurrent.futures import ThreadPoolExecutor
+
+def run_episode(client_id: int):
+    with HackathonEnv(base_url="http://localhost:8000") as env:
+        result = env.reset()
+        for i in range(10):
+            result = env.step(HackathonAction(message=f"Client {client_id}, step {i}"))
+        return client_id, result.observation.message_length
+
+# Run 4 episodes concurrently
+with ThreadPoolExecutor(max_workers=4) as executor:
+    results = list(executor.map(run_episode, range(4)))
+```
+
+## Development & Testing
+
+### Direct Environment Testing
+
+Test the environment logic directly without starting the HTTP server:
+
+```bash
+# From the server directory
+python3 server/hackathon_env_environment.py
+```
+
+This verifies that:
+- Environment resets correctly
+- Step executes actions properly
+- State tracking works
+- Rewards are calculated correctly
+
+### Running Locally
+
+Run the server locally for development:
+
+```bash
+uvicorn server.app:app --reload
+```
+
+## Project Structure
+
+```
+hackathon_env/
+├── .dockerignore         # Docker build exclusions
+├── __init__.py            # Module exports
+├── README.md              # This file
+├── openenv.yaml           # OpenEnv manifest
+├── pyproject.toml         # Project metadata and dependencies
+├── uv.lock                # Locked dependencies (generated)
+├── client.py              # HackathonEnv client
+├── models.py              # Action and Observation models
+└── server/
+    ├── __init__.py        # Server module exports
+    ├── hackathon_env_environment.py  # Core environment logic
+    ├── app.py             # FastAPI application (HTTP + WebSocket endpoints)
+    └── Dockerfile         # Container image definition
+```

hackathon_env/__init__.py

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+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""Hackathon Env Environment."""
+
+from .client import HackathonEnv
+from .models import HackathonAction, HackathonObservation
+
+__all__ = [
+    "HackathonAction",
+    "HackathonObservation",
+    "HackathonEnv",
+]

hackathon_env/client.py

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+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""Hackathon Env Environment Client."""
+
+from typing import Dict
+
+from openenv.core.client_types import StepResult
+from openenv.core.env_server.types import State
+from openenv.core import EnvClient
+
+from .models import HackathonAction, HackathonObservation
+
+
+class HackathonEnv(
+    EnvClient[HackathonAction, HackathonObservation]
+):
+    """
+    Client for the Hackathon Env Environment.
+
+    This client maintains a persistent WebSocket connection to the environment server,
+    enabling efficient multi-step interactions with lower latency.
+    Each client instance has its own dedicated environment session on the server.
+
+    Example:
+        >>> # Connect to a running server
+        >>> with HackathonEnv(base_url="http://localhost:8000") as client:
+        ...     result = client.reset()
+        ...     print(result.observation.echoed_message)
+        ...
+        ...     result = client.step(HackathonAction(message="Hello!"))
+        ...     print(result.observation.echoed_message)
+
+    Example with Docker:
+        >>> # Automatically start container and connect
+        >>> client = HackathonEnv.from_docker_image("hackathon_env-env:latest")
+        >>> try:
+        ...     result = client.reset()
+        ...     result = client.step(HackathonAction(message="Test"))
+        ... finally:
+        ...     client.close()
+    """
+
+    def _step_payload(self, action: HackathonAction) -> Dict:
+        """
+        Convert HackathonAction to JSON payload for step message.
+
+        Args:
+            action: HackathonAction instance
+
+        Returns:
+            Dictionary representation suitable for JSON encoding
+        """
+        return {
+            "message": action.message,
+        }
+
+    def _parse_result(self, payload: Dict) -> StepResult[HackathonObservation]:
+        """
+        Parse server response into StepResult[HackathonObservation].
+
+        Args:
+            payload: JSON response data from server
+
+        Returns:
+            StepResult with HackathonObservation
+        """
+        obs_data = payload.get("observation", {})
+        observation = HackathonObservation(
+            echoed_message=obs_data.get("echoed_message", ""),
+            message_length=obs_data.get("message_length", 0),
+            done=payload.get("done", False),
+            reward=payload.get("reward"),
+            metadata=obs_data.get("metadata", {}),
+        )
+
+        return StepResult(
+            observation=observation,
+            reward=payload.get("reward"),
+            done=payload.get("done", False),
+        )
+
+    def _parse_state(self, payload: Dict) -> State:
+        """
+        Parse server response into State object.
+
+        Args:
+            payload: JSON response from state request
+
+        Returns:
+            State object with episode_id and step_count
+        """
+        return State(
+            episode_id=payload.get("episode_id"),
+            step_count=payload.get("step_count", 0),
+        )

hackathon_env/models.py

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+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Data models for the Hackathon Env Environment.
+
+The hackathon_env environment is a simple test environment that echoes back messages.
+"""
+
+from pydantic import Field
+
+from openenv.core.env_server.types import Action, Observation
+
+
+class HackathonAction(Action):
+    """Action for the Hackathon Env environment - just a message to echo."""
+
+    message: str = Field(..., description="Message to echo back")
+
+
+class HackathonObservation(Observation):
+    """Observation from the Hackathon Env environment - the echoed message."""
+
+    echoed_message: str = Field(default="", description="The echoed message")
+    message_length: int = Field(default=0, description="Length of the echoed message")

hackathon_env/openenv.yaml

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+spec_version: 1
+name: hackathon_env
+type: space
+runtime: fastapi
+app: server.app:app
+port: 8000
+

hackathon_env/pyproject.toml

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+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+[build-system]
+requires = ["setuptools>=45", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "openenv-hackathon_env"
+version = "0.1.0"
+description = "Hackathon Env environment for OpenEnv"
+requires-python = ">=3.10"
+dependencies = [
+    # Core OpenEnv runtime (provides FastAPI server + HTTP client types)
+    # install from github
+    # "openenv-core[core] @ git+https://github.com/meta-pytorch/OpenEnv.git",
+    "openenv-core[core]>=0.2.0",
+    # Environment-specific dependencies
+    # Add all dependencies needed for your environment here
+    # Examples:
+    # "numpy>=1.19.0",
+    # "torch>=2.0.0",
+    # "gymnasium>=0.29.0",
+    # "openspiel>=1.0.0",
+    # "smolagents>=1.22.0,<2",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-cov>=4.0.0",
+]
+
+[project.scripts]
+# Server entry point - enables running via: uv run --project . server
+# or: python -m hackathon_env.server.app
+server = "hackathon_env.server.app:main"
+
+[tool.setuptools]
+include-package-data = true
+packages = ["hackathon_env", "hackathon_env.server"]
+package-dir = { "hackathon_env" = ".", "hackathon_env.server" = "server" }

hackathon_env/server/Dockerfile

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+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Multi-stage build using openenv-base
+# This Dockerfile is flexible and works for both:
+# - In-repo environments (with local OpenEnv sources)
+# - Standalone environments (with openenv from PyPI/Git)
+# The build script (openenv build) handles context detection and sets appropriate build args.
+
+ARG BASE_IMAGE=ghcr.io/meta-pytorch/openenv-base:latest
+FROM ${BASE_IMAGE} AS builder
+
+WORKDIR /app
+
+# Ensure git is available (required for installing dependencies from VCS)
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends git && \
+    rm -rf /var/lib/apt/lists/*
+
+# Build argument to control whether we're building standalone or in-repo
+ARG BUILD_MODE=in-repo
+ARG ENV_NAME=hackathon_env
+
+# Copy environment code (always at root of build context)
+COPY . /app/env
+
+# For in-repo builds, openenv is already vendored in the build context
+# For standalone builds, openenv will be installed via pyproject.toml
+WORKDIR /app/env
+
+# Ensure uv is available (for local builds where base image lacks it)
+RUN if ! command -v uv >/dev/null 2>&1; then \
+        curl -LsSf https://astral.sh/uv/install.sh | sh && \
+        mv /root/.local/bin/uv /usr/local/bin/uv && \
+        mv /root/.local/bin/uvx /usr/local/bin/uvx; \
+    fi
+    
+# Install dependencies using uv sync
+# If uv.lock exists, use it; otherwise resolve on the fly
+RUN --mount=type=cache,target=/root/.cache/uv \
+    if [ -f uv.lock ]; then \
+        uv sync --frozen --no-install-project --no-editable; \
+    else \
+        uv sync --no-install-project --no-editable; \
+    fi
+
+RUN --mount=type=cache,target=/root/.cache/uv \
+    if [ -f uv.lock ]; then \
+        uv sync --frozen --no-editable; \
+    else \
+        uv sync --no-editable; \
+    fi
+
+# Final runtime stage
+FROM ${BASE_IMAGE}
+
+WORKDIR /app
+
+# Copy the virtual environment from builder
+COPY --from=builder /app/env/.venv /app/.venv
+
+# Copy the environment code
+COPY --from=builder /app/env /app/env
+
+# Set PATH to use the virtual environment
+ENV PATH="/app/.venv/bin:$PATH"
+
+# Set PYTHONPATH so imports work correctly
+ENV PYTHONPATH="/app/env:$PYTHONPATH"
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD curl -f http://localhost:8000/health || exit 1
+
+# Run the FastAPI server
+# The module path is constructed to work with the /app/env structure
+CMD ["sh", "-c", "cd /app/env && uvicorn server.app:app --host 0.0.0.0 --port 8000"]

hackathon_env/server/__init__.py

@@ -0,0 +1,11 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""Hackathon Env environment server components."""
+
+from .hackathon_env_environment import HackathonEnvironment
+
+__all__ = ["HackathonEnvironment"]

hackathon_env/server/app.py

@@ -0,0 +1,81 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+FastAPI application for the Hackathon Env Environment.
+
+This module creates an HTTP server that exposes the HackathonEnvironment
+over HTTP and WebSocket endpoints, compatible with EnvClient.
+
+Endpoints:
+    - POST /reset: Reset the environment
+    - POST /step: Execute an action
+    - GET /state: Get current environment state
+    - GET /schema: Get action/observation schemas
+    - WS /ws: WebSocket endpoint for persistent sessions
+
+Usage:
+    # Development (with auto-reload):
+    uvicorn server.app:app --reload --host 0.0.0.0 --port 8000
+
+    # Production:
+    uvicorn server.app:app --host 0.0.0.0 --port 8000 --workers 4
+
+    # Or run directly:
+    python -m server.app
+"""
+
+try:
+    from openenv.core.env_server.http_server import create_app
+except Exception as e:  # pragma: no cover
+    raise ImportError(
+        "openenv is required for the web interface. Install dependencies with '\n    uv sync\n'"
+    ) from e
+
+# Import from local models.py (PYTHONPATH includes /app/env in Docker)
+from models import HackathonAction, HackathonObservation
+from .hackathon_env_environment import HackathonEnvironment
+
+
+# Create the app with web interface and README integration
+app = create_app(
+    HackathonEnvironment,
+    HackathonAction,
+    HackathonObservation,
+    env_name="hackathon_env",
+    max_concurrent_envs=1,  # increase this number to allow more concurrent WebSocket sessions
+)
+
+
+def main(host: str = "0.0.0.0", port: int = 8000):
+    """
+    Entry point for direct execution via uv run or python -m.
+
+    This function enables running the server without Docker:
+        uv run --project . server
+        uv run --project . server --port 8001
+        python -m hackathon_env.server.app
+
+    Args:
+        host: Host address to bind to (default: "0.0.0.0")
+        port: Port number to listen on (default: 8000)
+
+    For production deployments, consider using uvicorn directly with
+    multiple workers:
+        uvicorn hackathon_env.server.app:app --workers 4
+    """
+    import uvicorn
+
+    uvicorn.run(app, host=host, port=port)
+
+
+if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--port", type=int, default=8000)
+    args = parser.parse_args()
+    main(port=args.port)

hackathon_env/server/hackathon_env_environment.py

@@ -0,0 +1,101 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Hackathon Env Environment Implementation.
+
+A simple test environment that echoes back messages sent to it.
+Perfect for testing HTTP server infrastructure.
+"""
+
+from uuid import uuid4
+
+from openenv.core.env_server.interfaces import Environment
+from openenv.core.env_server.types import State
+
+from models import HackathonAction, HackathonObservation
+
+
+class HackathonEnvironment(Environment):
+    """
+    A simple echo environment that echoes back messages.
+
+    This environment is designed for testing the HTTP server infrastructure.
+    It maintains minimal state and simply echoes back whatever message it receives.
+
+    Example:
+        >>> env = HackathonEnvironment()
+        >>> obs = env.reset()
+        >>> print(obs.echoed_message)  # "Hackathon Env environment ready!"
+        >>>
+        >>> obs = env.step(HackathonAction(message="Hello"))
+        >>> print(obs.echoed_message)  # "Hello"
+        >>> print(obs.message_length)  # 5
+    """
+
+    # Enable concurrent WebSocket sessions.
+    # Set to True if your environment isolates state between instances.
+    # When True, multiple WebSocket clients can connect simultaneously, each
+    # getting their own environment instance (when using factory mode in app.py).
+    SUPPORTS_CONCURRENT_SESSIONS: bool = True
+
+    def __init__(self):
+        """Initialize the hackathon_env environment."""
+        self._state = State(episode_id=str(uuid4()), step_count=0)
+        self._reset_count = 0
+
+    def reset(self) -> HackathonObservation:
+        """
+        Reset the environment.
+
+        Returns:
+            HackathonObservation with a ready message
+        """
+        self._state = State(episode_id=str(uuid4()), step_count=0)
+        self._reset_count += 1
+
+        return HackathonObservation(
+            echoed_message="Hackathon Env environment ready!",
+            message_length=0,
+            done=False,
+            reward=0.0,
+        )
+
+    def step(self, action: HackathonAction) -> HackathonObservation:  # type: ignore[override]
+        """
+        Execute a step in the environment by echoing the message.
+
+        Args:
+            action: HackathonAction containing the message to echo
+
+        Returns:
+            HackathonObservation with the echoed message and its length
+        """
+        self._state.step_count += 1
+
+        message = action.message
+        length = len(message)
+
+        # Simple reward: longer messages get higher rewards
+        reward = length * 0.1
+
+        return HackathonObservation(
+            echoed_message=message,
+            message_length=length,
+            done=False,
+            reward=reward,
+            metadata={"original_message": message, "step": self._state.step_count},
+        )
+
+    @property
+    def state(self) -> State:
+        """
+        Get the current environment state.
+
+        Returns:
+            Current State with episode_id and step_count
+        """
+        return self._state

hackathon_env/server/requirements.txt

@@ -0,0 +1,6 @@
+openenv[core]>=0.2.0
+fastapi>=0.115.0
+uvicorn>=0.24.0
+
+
+

train.py

@@ -0,0 +1,154 @@
+"""
+Minimal Training Script for OpenEnv Hackathon
+==============================================
+Uses HuggingFace TRL's GRPOTrainer with OpenEnv environment integration.
+
+Run in Google Colab with GPU runtime:
+    !pip install "openenv-core[core]>=0.2.1" trl transformers torch accelerate
+    # Or with Unsloth for 2x faster training:
+    !pip install unsloth "openenv-core[core]>=0.2.1" trl
+
+Usage:
+    python train.py --env_url https://<your-hf-space>.hf.space
+"""
+
+import argparse
+
+from hackathon_env.client import HackathonEnv
+from hackathon_env.models import HackathonAction
+
+
+def collect_rollouts(env_url: str, prompts: list[str]) -> list[dict]:
+    """
+    Collect rollouts by interacting with the OpenEnv environment.
+
+    Args:
+        env_url: URL of the deployed OpenEnv environment
+        prompts: List of prompts to send to the environment
+
+    Returns:
+        List of rollout dicts with prompt, completion, and reward
+    """
+    rollouts = []
+
+    with HackathonEnv(base_url=env_url) as env:
+        for prompt in prompts:
+            env.reset()
+            result = env.step(HackathonAction(message=prompt))
+
+            rollouts.append({
+                "prompt": prompt,
+                "completion": result.observation.echoed_message,
+                "reward": result.reward,
+            })
+
+    return rollouts
+
+
+def reward_function(completions: list[str], **kwargs) -> list[float]:
+    """
+    Reward function for GRPO training.
+    Extracts rewards from environment rollout results.
+    """
+    env_rewards = kwargs.get("env_reward", [])
+    if env_rewards:
+        return env_rewards
+    # Fallback: simple length-based reward
+    return [len(c) * 0.1 for c in completions]
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Train with OpenEnv + TRL GRPO")
+    parser.add_argument(
+        "--env_url",
+        type=str,
+        default="http://localhost:8000",
+        help="URL of the OpenEnv environment server",
+    )
+    parser.add_argument(
+        "--model_name",
+        type=str,
+        default="Qwen/Qwen2.5-0.5B-Instruct",
+        help="Model to train",
+    )
+    parser.add_argument(
+        "--use_unsloth",
+        action="store_true",
+        help="Use Unsloth for faster training",
+    )
+    parser.add_argument(
+        "--num_epochs",
+        type=int,
+        default=1,
+        help="Number of training epochs",
+    )
+    args = parser.parse_args()
+
+    print(f"Environment URL: {args.env_url}")
+    print(f"Model: {args.model_name}")
+    print(f"Using Unsloth: {args.use_unsloth}")
+
+    # --- Step 1: Verify environment connectivity ---
+    print("\n[1/3] Verifying environment connection...")
+    with HackathonEnv(base_url=args.env_url) as env:
+        result = env.reset()
+        print(f"  Environment ready: {result.observation.echoed_message}")
+
+        test_result = env.step(HackathonAction(message="test"))
+        print(f"  Test step reward: {test_result.reward}")
+
+    # --- Step 2: Load model ---
+    print("\n[2/3] Loading model...")
+    if args.use_unsloth:
+        from unsloth import FastLanguageModel
+
+        model, tokenizer = FastLanguageModel.from_pretrained(
+            model_name=args.model_name,
+            max_seq_length=2048,
+            load_in_4bit=True,
+        )
+        model = FastLanguageModel.get_peft_model(
+            model,
+            r=16,
+            target_modules=["q_proj", "k_proj", "v_proj", "o_proj",
+                            "gate_proj", "up_proj", "down_proj"],
+            lora_alpha=16,
+            lora_dropout=0,
+            bias="none",
+            use_gradient_checkpointing="unsloth",
+        )
+    else:
+        from transformers import AutoModelForCausalLM, AutoTokenizer
+
+        tokenizer = AutoTokenizer.from_pretrained(args.model_name)
+        model = AutoModelForCausalLM.from_pretrained(args.model_name)
+
+    # --- Step 3: Train with GRPO ---
+    print("\n[3/3] Starting GRPO training...")
+    from trl import GRPOTrainer, GRPOConfig
+
+    training_args = GRPOConfig(
+        output_dir="./output",
+        num_train_epochs=args.num_epochs,
+        per_device_train_batch_size=2,
+        gradient_accumulation_steps=4,
+        learning_rate=5e-6,
+        max_completion_length=256,
+        logging_steps=1,
+        save_steps=100,
+        report_to="none",
+    )
+
+    trainer = GRPOTrainer(
+        model=model,
+        processing_class=tokenizer,
+        reward_funcs=[reward_function],
+        args=training_args,
+    )
+
+    trainer.train()
+    print("\nTraining complete! Model saved to ./output")
+
+
+if __name__ == "__main__":
+    main()