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.
npx skills add jscraik/Agent-Skills --skill codex-environment-creatorgit clone --depth 1 https://github.com/jscraik/Agent-SkillsWrote 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/jscraik/agent-skills/codex-environment-creator)<a href="https://agentmods.dev/skills/jscraik/agent-skills/codex-environment-creator"><img src="https://agentmods.dev/badge/skills/jscraik/agent-skills/codex-environment-creator/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/jscraik/agent-skills/codex-environment-creator"><img src="https://agentmods.dev/badge/skills/jscraik/agent-skills/codex-environment-creator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00040 | $0.01952 |
| Opus 5 | $0.00020 | $0.00976 |
| Sonnet 5 | $0.00008 | $0.00390 |
| Haiku 4.5 | $0.00004 | $0.00195 |
Grade A, and why
codex-environment-creator scanned grade A with 0 findings 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 8d 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex Environment Creator
Philosophy
- Treat Codex environment setup as a repo contract, not a one-off shell note.
- Prefer the target repo's existing wrappers, package manager, and validators.
- Fix path and spelling drift before changing behavior.
When To Use
- The user asks to create, repair, audit, or update a Codex environment file.
- A project needs
.codex/environments/environment.tomlto bootstrap dependencies or expose Codex actions. - A Codex runtime needs
$CODEX_HOME/environments.tomltriaged for local, remote, or disabled execution environment selection. - A Codex exec-server provider needs URL or stdio transport entries validated.
- There is drift between
.codex/environments/environment.toml, misspelled.codex/environmentals/*paths, repo docs, or setup scripts. - Codex environment cache behavior, setup script churn, or action names need triage.
Avoid
- Editing cloud-only Codex environment settings when no repo file is involved.
- Replacing project-owned setup wrappers with generic install commands.
- Running broad installs or network-heavy commands before the target repo contract is known.
Inputs
- target project path
- requested mode: create, triage, or update
- existing environment files or misspelled aliases
- repo setup, maintenance, and validation commands
- desired actions and icons
- current Codex docs, live fork, or codex-repo evidence when schema behavior is uncertain
- evidence source for whether the request is project bootstrap/actions or runtime exec-server provider selection
Outputs
- environment file changes or triage findings
- canonical path decision
- setup and action contract
- validation evidence
- cache or rollout notes
- Schema-bound outputs include
schema_version.
Execution Boundaries
- Edit only canonical repo-owned environment files unless the user explicitly asks for a migration or external target.
- The agent may create
.codex/environments/and.codex/environments/environment.tomlinside the target project. $CODEX_HOME/environments.tomlis a user/runtime exec-server provider file, not a project bootstrap/action file; inspect or edit it only when the user asks about runtime environment selection, remote exec servers, or disabled shell/filesystem access.- The agent may inspect package and tooling files, but should run install or setup commands only when they are the smallest safe validation step.
- The user owns cloud environment administration, cache resets, secret updates, and destructive cleanup decisions unless they explicitly delegate them.
What ships with it
6 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.
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.
- 8d ago First seen · 144 lines · 40 tokens per session scan A e4f4572fff63
codex-environment-creator is a skill published in the GitHub repository jscraik/Agent-Skills (8 stars, last pushed 10d ago), licensed Apache-2.0. It adds 40 tokens to every session and 1,952 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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