OpenEnv is a framework for creating, deploying, and using isolated execution environments through simple APIs modeled on Gymnasium. It is intended for researchers and developers training agents with reinforcement learning, as well as creators who need secure environments that can be deployed and accessed through familiar protocols. The catalogue add-ons provide agent integrations and workflows for using OpenEnv.
Borrowing it
Nothing to install: this file belongs to huggingface/OpenEnv. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/huggingface/OpenEnv/main/.claude/skills/generate-openenv-env/SKILL.mdgit clone --depth 1 https://github.com/huggingface/OpenEnvWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/huggingface/openenv/generate-openenv-env)<a href="https://agentmods.dev/skills/huggingface/openenv/generate-openenv-env"><img src="https://agentmods.dev/badge/skills/huggingface/openenv/generate-openenv-env/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/huggingface/openenv/generate-openenv-env"><img src="https://agentmods.dev/badge/skills/huggingface/openenv/generate-openenv-env.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00079 | $0.01595 |
| Opus 5.5 | $0.00032 | $0.00638 |
| Sonnet 5.5 | $0.00016 | $0.00319 |
| Haiku 4.5 | $0.00008 | $0.00160 |
Grade A, and why
generate-openenv-env scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl http://localhost:8000/health How it starts
The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/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) andreferences/openenv-docs-environment-builder.md. - Prefer
envs/textarena_envfor external-library wrappers with richer state. - Add one simpler baseline (for example
envs/snake_envorenvs/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.
What ships with it
16 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- agents/openai.yaml 230 B
- assets/openenv_env_template/__init__.py 479 B runs code
- assets/openenv_env_template/.dockerignore 94 B
- assets/openenv_env_template/client.py 3.2 KB runs code
- assets/openenv_env_template/models.py 938 B runs code
- assets/openenv_env_template/openenv.yaml 377 B
- assets/openenv_env_template/pyproject.toml 1.3 KB
- assets/openenv_env_template/README.md 7.8 KB
- assets/openenv_env_template/server/__ENV_NAME___environment.py 3.4 KB runs code
- assets/openenv_env_template/server/__init__.py 379 B runs code
- assets/openenv_env_template/server/app.py 2.6 KB runs code
- assets/openenv_env_template/server/Dockerfile 3.1 KB
- assets/openenv_env_template/server/requirements.txt 48 B
- references/env-generation-checklist.md 3.5 KB
- references/openenv-docs-environment-builder.md 16 KB
- references/openenv-tutorial-01-environments.md 39 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago Changed 22042f2f730b
- 1mo ago First seen · 165 lines · 79 tokens per session scan A 852d7d2d65fa
generate-openenv-env is a skill published in the GitHub repository huggingface/OpenEnv (2,739 stars, last pushed 8d ago), licensed BSD-3-Clause. It adds 79 tokens to every session and 1,595 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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