generate-openenv-env

Generate OpenEnv environments from a concrete use case (for example, "generate an env for the library textarena"). Use when asked to design or implement a new…

npx skills add https://github.com/huggingface/openenv --skill generate-openenv-env

/generate-openenv-env

Build a production-ready OpenEnv environment from a use-case prompt.

Execute Workflow

When invoked, execute this workflow end-to-end.

1. Parse the use case and name the environment

Derive a repo path in the form envs/<name>_env/.

  • Normalize to snake_case.
  • Keep names short and domain-specific.
  • Example: "generate an env for the library textarena" -> envs/textarena_env/.

2. Research the target library/API before coding

Gather the minimum interface facts needed to implement reset, step, and state serialization.

  • Search local docs/examples first.
  • Search upstream docs/repo for the target library when local context is insufficient.
  • Extract only implementation-critical details:
    • installation/dependency requirements
    • environment creation API
    • action format
    • observation format
    • reward and done semantics
    • special setup (model files, downloads, auth, etc.)

3. Mine matching OpenEnv examples

Select 2-3 existing environments as implementation templates.

  • Always read references/openenv-tutorial-01-environments.md (Part 10) and references/openenv-docs-environment-builder.md.
  • Prefer envs/textarena_env for external-library wrappers with richer state.
  • Add one simpler baseline (for example envs/snake_env or envs/echo_env) to keep the implementation minimal.
  • Follow patterns, do not copy blindly.
  • Exclude generated or vendored files when mining examples (.venv/, build/, site-packages/, __pycache__/).

For a compact checklist and mapping, read references/env-generation-checklist.md.

4. Ask focused implementation questions

Ask only the questions that materially affect architecture. Use the question bank in references/env-generation-checklist.md.

Cover at least:

  • action space contract
  • observation fields needed by agents
  • reward design and terminal conditions
  • episode/session configuration knobs
  • deployment target and dependency constraints

If answers are unavailable, proceed with explicit assumptions and document them.

5. Choose the environment archetype

Choose one archetype before scaffolding:

  • Typed step/reset environment (default): use EnvClient + typed Action/Observation[/State] models.
  • MCP tool environment: use MCPEnvironment + MCPToolClient and MCP action/observation types.
  • Specialized client flow (rare): only when the standard clients cannot express required behavior (for example local+remote hybrid clients).

6. Scaffold the environment

Use the CLI to scaffold:

PYTHONPATH=src uv run openenv init <name>_env --output-dir envs

This generates all files with correct placeholders replaced, including pyproject.toml, Dockerfile, and uv.lock.

If the CLI is unavailable (import errors, missing dependencies), create the structure manually matching:

envs/<name>_env/
├── __init__.py
├── client.py
├── models.py
├── openenv.yaml
├── pyproject.toml
└── server/
    ├── __init__.py
    ├── app.py
    ├── <name>_environment.py
    └── Dockerfile

Use assets/openenv_env_template/ as a reference for file contents when scaffolding manually.

7. Implement with OpenEnv contracts

Implement these files in order:

  1. models.py
  2. server/<name>_environment.py
  3. server/app.py
  4. client.py
  5. openenv.yaml
  6. README.md

Use these standards:

  • Use typed models (Action/Observation/State).
  • Use create_app(<factory_or_class>, ActionType, ObservationType, env_name=...) in server/app.py. Pass a class or factory callable, not an instantiated environment.
  • Dual-import pattern (required in server/app.py and server/<name>_environment.py): Use try: from ..models import X / except ImportError: from models import X. Relative imports work in-repo (PYTHONPATH=src:envs); bare imports work in Docker (PYTHONPATH=/app/env). The same pattern applies to intra-server imports (e.g., from .foo import Bar vs from server.foo import Bar).
  • client.py uses EnvClient[ActionType, ObservationType, State] (three type parameters).
  • Keep server logic in server/, keep client parsing in client.py.
  • Expose config through environment variables when behavior is likely to vary.
  • Keep reward logic inside the environment.
  • Prefer reset/step signatures compatible with Environment:
    • reset(seed=None, episode_id=None, **kwargs)
    • step(action, timeout_s=None, **kwargs)
  • Set SUPPORTS_CONCURRENT_SESSIONS=True only when isolation is real. Set max_concurrent_envs in create_app accordingly (1 when False, >1 when True).
  • For MCP/tool-call UIs that send stringified JSON arguments, add action validators/parsers in server/app.py.
  • Export public client/models symbols in __init__.py.
  • Keep openenv.yaml aligned with current scaffold format (spec_version: 1, name, type, runtime, app, port).
  • Avoid training/evaluation code paths in this skill.

8. Validate before handoff

Run the narrowest useful checks:

# Verify in-repo imports work (catches missing dual-import pattern)
PYTHONPATH=src:envs uv run python -c "from envs.<name>_env.server.<name>_environment import <ClassName>Environment"

# Build and validate
cd envs/<name>_env
openenv build
openenv validate --level static --skip-build
PYTHONPATH=src:envs uv run pytest envs/<name>_env -q

If tests do not exist, run a smoke check:

PYTHONPATH=src:envs uv run uvicorn envs.<name>_env.server.app:app --port 8000
curl http://localhost:8000/health
openenv validate --url http://localhost:8000

9. Deliver with assumptions and gaps

Report:

  • files created/updated
  • chosen archetype (typed vs MCP vs specialized)
  • assumptions made due to missing answers
  • validation commands executed and outcomes
  • remaining risks or follow-up questions

Guardrails

  • Do not route into model training/evaluation workflows.
  • Do not invent library APIs; confirm against source docs.
  • Do not skip reading at least one existing OpenEnv env before implementation.
  • Do not copy outdated manifest patterns from older envs (name/version/action/observation-only manifests).
  • Do not copy build artifacts or virtualenv files from example envs.
  • Do not set max_concurrent_envs > 1 unless the environment explicitly supports concurrent sessions.

More skills from huggingface

sync-models
huggingface
Sync chat-ui's model config with the HuggingFace router — add descriptions for new models, flag reasoning-capable ones, enable artifacts for models with 32B+…
custom-blocks
huggingface
Use when the user has written (or wants to write) a `ModularPipelineBlocks` subclass in a local Python file and needs to package it into a Hub-uploadable…
self-review
huggingface
Use before opening a PR, or whenever asked to self-review a diffusers contribution. Applies the same rubric as the `@claude` CI (checks the diff against…
hf-cloud-sagemaker-production-defaults
huggingface
Create a SageMaker endpoint (real-time or async) with autoscaling, CloudWatch alarms, and tagging enabled by default. Use this skill whenever about to create a…
hf-cloud-serving-image-selection
huggingface
Pick the right serving container for a SageMaker model deployment and find its current image URI. Use this skill whenever about to deploy a model to a…
Hugging Face Cli
huggingface
Execute Hugging Face Hub operations using the `hf` CLI. Use when the user needs to download models/datasets/spaces, upload files to Hub repositories, create repos, manage local cache, or run compute jobs on HF infrastructure. Covers authentication, file transfers, repository creation, cache operations, and cloud compute.
Hugging Face Datasets
huggingface
Create and manage datasets on Hugging Face Hub. Supports initializing repos, defining configs/system prompts, streaming row updates, and SQL-based dataset querying/transformation. Designed to work alongside HF MCP server for comprehensive dataset workflows.
Hugging Face Evaluation
huggingface
Add and manage evaluation results in Hugging Face model cards. Supports extracting eval tables from README content, importing scores from Artificial Analysis API, and running custom model evaluations with vLLM/lighteval. Works with the model-index metadata format.