A bounded review-and-fix cycle that uses the Codex command-line tool as an outside code critic for Elixir and Phoenix changes. It reviews changes, applies approved fixes, verifies them, and repeats for a limited number of rounds.

Use it to review uncommitted or branch differences, fix approved findings, run compilation and tests, and check the changes again before opening a pull request.

It provides another review perspective before a pull request while preventing endless review loops and leaving commits and pushes under the developer’s control.

codex-loop — Skill for Claude Code by oliver-kriska

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.

Any agent

npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-loop

Clone the repo

git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix

Made for: Claude Code.

Or install phx, the plugin that ships this one along with the rest of its 50 skills, 26 agents, 8 hooks.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/codex-loop/github.svg)](https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/codex-loop)

Your own site

<a href="https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/codex-loop"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/codex-loop/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/codex-loop"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/codex-loop.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,592 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 2 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 72
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.
medium Excessive Agency · line 21
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.

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00052	$0.01592
Opus 5.5	$0.00021	$0.00637
Sonnet 5.5	$0.00010	$0.00318
Haiku 4.5	$0.00005	$0.00159

Measured 6d ago against content hash de8b867d9fe0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

codex-loop 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 6d 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.

`model`/`review_model = "$MODEL"` in `~/.codex/config.toml`.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

phx-codex-loop — 89% identical, 40 lines differ

plugins/elixir-phoenix/skills/codex-loop/SKILL.md · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex Loop (fix until clean)

Critic→Refiner loop with the Codex CLI as external critic: review → fix approved findings → verify → re-review, until codex is clean or rounds run out. Codex reviews; Claude fixes. Complements /phx:review (Claude panel) — run either or both before a PR.

Usage

/phx:codex-loop                    # diff vs default branch, interactive
/phx:codex-loop --uncommitted      # staged + unstaged + untracked
/phx:codex-loop --base develop     # explicit base branch
/phx:codex-loop --auto             # auto-approve P0/P1/P2, skip P3
/phx:codex-loop --max-rounds 2     # default 3

Iron Laws

BOUNDED rounds — never exceed --max-rounds (default 3) — each round costs codex quota; report remaining findings instead of looping on
Verify BEFORE re-review — mix compile --warnings-as-errors + tests must pass before burning a codex round on broken code
NEVER commit or push — leave git to the user
Codex findings get Iron Law scrutiny — decline suggestions that violate an Iron Law, with explanation in the round report
Skipped findings are reported, never dropped — every finding ends as fixed, declined (with reason), or deferred-by-user
Missing CLI stops the skill with an install hint — suggest /phx:review as the codex-free alternative; never crash

Workflow

Step 1: Preflight

Run command -v codex. If missing: STOP. Show the install hint (brew install codex or npm i -g @openai/codex, then codex login; codex doctor to diagnose) and suggest /phx:review.

Then two cheap checks that save review rounds:

Dirty tree (git status --short, only when using --base): codex inspects working-tree state too and WILL flag local dirt (stray edits, dirty submodules) as findings. Surface the dirt and ask: clean/stash first, or proceed knowing round 1 may spend findings on it.
Missing rubric: if AGENTS.md has no ## Review guidelines section, note once that /phx:init installs the Elixir rubric that steers codex priorities — then proceed (it works without, on defaults).

Read the full file on GitHub · 140 lines

Files

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.

references/codex-cli.md 5.7 KB

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.

6d ago Changed · +10 lines scan A → B de8b867d9fe0
1mo ago First seen · 130 lines · 52 tokens per session scan A 25024770b147

Subscribe to this mod's changes

codex-loop is a skill published in the GitHub repository oliver-kriska/claude-elixir-phoenix (569 stars, last pushed yesterday), licensed MIT. It adds 52 tokens to every session and 1,592 once invoked, about $0.0002 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 2026-09-03.

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codex-loop