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 ondrej-svec/heart-of-gold-toolkit --skill codexgit clone --depth 1 https://github.com/ondrej-svec/heart-of-gold-toolkitWrote 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/ondrej-svec/heart-of-gold-toolkit/codex)<a href="https://agentmods.dev/skills/ondrej-svec/heart-of-gold-toolkit/codex"><img src="https://agentmods.dev/badge/skills/ondrej-svec/heart-of-gold-toolkit/codex/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/ondrej-svec/heart-of-gold-toolkit/codex"><img src="https://agentmods.dev/badge/skills/ondrej-svec/heart-of-gold-toolkit/codex.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Excessive Agency · line 85 Skill selects an external model or provider that may use a different account or billing plan than the operator expects. Undisclosed model switches can cause unexpected cost or quota consumption.Fix: Remove the model/provider override or disclose it prominently and require explicit operator approval before invoking an external coding CLI or billed model.
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 | $0.00038 | $0.01691 |
| Opus 5 | $0.00019 | $0.00846 |
| Sonnet 5 | $0.00008 | $0.00338 |
| Haiku 4.5 | $0.00004 | $0.00169 |
Grade A, and why
codex 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 12d 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 — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex CLI Skill Guide
Available Models
| Model | Best for |
|---|---|
gpt-5.5 |
Flagship (released 2026-04-23) — complex coding, computer use, knowledge work, research workflows. ChatGPT sign-in only — not available with API-key auth. Fall back to gpt-5.4 if not in the user's model picker yet. |
gpt-5.4 |
Professional coding with strong reasoning + tool use. Default fallback when gpt-5.5 is unavailable. |
gpt-5.4-mini |
Faster/cheaper for lighter coding tasks and subagents |
gpt-5.3-codex |
Complex software engineering with industry-leading coding capabilities |
gpt-5.3-codex-spark |
Near-instant real-time coding iteration (ChatGPT Pro research preview) |
Default recommendation: gpt-5.5 for complex tasks (with gpt-5.4 fallback), gpt-5.4-mini for speed.
Running a Task
- Ask the user (via
AskUserQuestion) which model to use (default:gpt-5.5, fallbackgpt-5.4) AND which reasoning effort (xhigh,high,medium, orlow) in a single prompt with two questions. - Select the sandbox mode required for the task; default to
--sandbox read-onlyunless edits or network access are necessary. - Assemble the command with the appropriate options:
-m, --model <MODEL>--config model_reasoning_effort="<xhigh|high|medium|low>"--sandbox <read-only|workspace-write|danger-full-access>--full-auto-C, --cd <DIR>--skip-git-repo-check"your prompt here"(as final positional argument)
- Always use
--skip-git-repo-check. - IMPORTANT: By default, append
2>/dev/nullto allcodex execcommands to suppress thinking tokens (stderr). Only show stderr if the user explicitly requests to see thinking tokens or if debugging is needed. - Run the command, capture stdout/stderr (filtered as appropriate), and summarize the outcome for the user.
- After Codex completes, inform the user: "You can resume this Codex session at any time by saying 'codex resume' or asking me to continue."
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.
- 12d ago First seen · 94 lines · 38 tokens per session scan A 3bce8ba4446f
codex is a skill published in the GitHub repository ondrej-svec/heart-of-gold-toolkit (19 stars, last pushed 22d ago), licensed MIT. It adds 38 tokens to every session and 1,691 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 2026-08-30.
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