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 markus-global/markus --skill codexgit clone --depth 1 https://github.com/markus-global/markusWrote 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/markus-global/markus/codex)<a href="https://agentmods.dev/skills/markus-global/markus/codex"><img src="https://agentmods.dev/badge/skills/markus-global/markus/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/markus-global/markus/codex"><img src="https://agentmods.dev/badge/skills/markus-global/markus/codex.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 4 findings, 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 24 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.
- high Agent Snooping · line 43 Skill reads from agent configuration directories (.claude/, .codex/, .gemini/). These directories may contain API keys, personal settings, and other credentials that the skill has no legitimate need to access.Fix: Remove all code or instructions that access agent configuration directories (.claude/, .codex/, .gemini/). If configuration values are needed, pass them explicitly as parameters or environment variabl
- medium Excessive Agency · line 29 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
- medium Excessive Agency · line 195 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 | $0.00022 | $0.01996 |
| Opus 5.5 | $0.00009 | $0.00798 |
| Sonnet 5.5 | $0.00004 | $0.00399 |
| Haiku 4.5 | $0.00002 | $0.00200 |
Grade B, and why
codex scanned grade B 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
**Note:** `OPENAI_BASE_URL` is deprecated and no longer supported by Codex CLI. Custom endpoint configuration should use `~/.codex/config.toml`. How it starts
The opening of the file, as written. The whole thing — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex
Codex (codex binary) is OpenAI's agentic coding CLI. Markus invokes it via invoke_coding_tool({ tool: "codex", ... }). Use it for fast, focused changes where speed and non-interactive automation matter more than deep multi-turn exploration.
Installation
npm install -g @openai/codex
codex --version
Verify with markus doctor. Requires authentication via codex login or CODEX_API_KEY env var for non-interactive mode.
How Markus Invokes Codex
Markus runs Codex in fully automated, non-interactive mode:
codex exec --full-auto --json --skip-git-repo-check "<prompt>"
| Flag | Purpose |
|---|---|
exec --full-auto |
Non-interactive mode — auto-approves all file edits and shell commands |
--json |
Emits JSONL events for structured progress parsing |
--skip-git-repo-check |
Allows running outside strict git repo requirements |
Additional args can be configured via CodingToolConfig.defaultArgs.
Full-Auto Approval Mode
In a Markus agent session, there is no human at the terminal to approve Codex actions. The exec --full-auto mode is essential:
- Codex can edit files and run commands without prompting
- All actions happen within the sandbox (see below)
- If Codex would normally ask "Allow this edit?", it proceeds automatically
Note: OPENAI_BASE_URL is deprecated and no longer supported by Codex CLI. Custom endpoint configuration should use ~/.codex/config.toml.
Implication: Write precise prompts with clear scope boundaries. Codex will act autonomously on whatever the prompt authorizes.
AGENTS.md Context File
Codex reads project-level instruction files to understand repo conventions. The standard file is AGENTS.md in the repository root — a markdown file describing:
- Project structure and architecture
- Coding conventions and patterns
- Test commands and CI expectations
- Areas that are off-limits or require caution
If the repo already has AGENTS.md, Codex uses it automatically. Ensure it stays accurate for the project.
What ships with it
1 file 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.
- 1mo ago First seen · 218 lines · 22 tokens per session scan B b43b4c5025e5
codex is a skill published in the GitHub repository markus-global/markus (205 stars, last pushed today), licensed Apache-2.0. It adds 22 tokens to every session and 1,996 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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