generate-openenv-env

generate-openenv-env is a skill for Claude Code, Codex from huggingface/OpenEnv. It costs 79 tokens per session (1,591 once invoked), scanned A, original, BSD-3-Clause.

A development skill for building OpenEnv environments, which are software setups that let AI agents interact with a library or API through defined actions and results.

In plain words
What is it for?
It is for researching a library, choosing implementation examples, and creating an environment under `envs/` with reset, step, and saved-state behavior.
Why use it?
It helps turn a concrete use case into an environment without guessing how the target library works or how OpenEnv environments are structured.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/huggingface/openenv/generate-openenv-env
Any agent
npx skills add huggingface/OpenEnv --skill generate-openenv-env
Clone the repo
git clone --depth 1 https://github.com/huggingface/OpenEnv

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for generate-openenv-env

README.md
[![agentmods](https://agentmods.dev/badge/skills/huggingface/openenv/generate-openenv-env.svg)](https://agentmods.dev/skills/huggingface/openenv/generate-openenv-env)
Your own site
<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="Measured on agentmods" height="20"></a>
Per session 79 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,591 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00079 $0.01591
Opus 5 $0.00039 $0.00796
Sonnet 5 $0.00016 $0.00318
Haiku 4.5 $0.00008 $0.00159

Measured 3d ago against content hash 852d7d2d65fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 3d ago.

The scan reads SKILL.md. This mod also ships 6 executable files (assets/openenv_env_template/__init__.py, assets/openenv_env_template/client.py, assets/openenv_env_template/models.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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
.claude/skills/generate-openenv-env/SKILL.md · 165 lines

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) 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.

Read the full file on GitHub · 165 lines

Changes

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.

  1. 3d ago First seen · 165 lines · 79 tokens per session scan A 852d7d2d65fa

Subscribe to this mod's changes

generate-openenv-env is a skill published in the GitHub repository huggingface/OpenEnv (2,531 stars, last pushed 5d ago), licensed BSD-3-Clause. It adds 79 tokens to every session and 1,591 once invoked, about $0.0004 per session on Opus 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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