phx-codex-loop

phx-codex-loop is a skill for Codex from oliver-kriska/claude-elixir-phoenix. It costs 55 tokens per session (1,362 once invoked), scanned A, a copy of codex-loop, MIT.

A bounded review-and-fix cycle that uses the Codex command-line tool as an external reviewer for Elixir and Phoenix changes. It verifies fixes before sending the changes for another review.

In plain words
What is it for?
Use it to review committed or uncommitted changes, fix accepted findings, run compilation and tests, and repeat the review for a limited number of rounds.
Why use it?
It reduces the chance of opening a pull request with known review findings or code that does not compile or pass its tests.

Skill for Codex

Written for Codex: runs codex exec. Also seen: names the AskUserQuestion tool; mentions AGENTS.md; mentions Codex.

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/oliver-kriska/claude-elixir-phoenix/phx-codex-loop
Any agent
npx skills add oliver-kriska/claude-elixir-phoenix --skill phx-codex-loop
Clone the repo
git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix

Made for: 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 phx-codex-loop

README.md
[![agentmods](https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/phx-codex-loop.svg)](https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/phx-codex-loop)
Your own site
<a href="https://agentmods.dev/skills/oliver-kriska/claude-elixir-phoenix/phx-codex-loop"><img src="https://agentmods.dev/badge/skills/oliver-kriska/claude-elixir-phoenix/phx-codex-loop.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,362 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 89% copy Near-identical to another mod 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 5.1 $0.00055 $0.01362
Opus 5 $0.00028 $0.00681
Sonnet 5 $0.00011 $0.00272
Haiku 4.5 $0.00006 $0.00136

Measured 2d ago against content hash 3342ff32ae7d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

phx-codex-loop 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 2d 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.

Origin

This is a copy

89% identical to codex-loop — 40 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

targets/amp/skills/phx-codex-loop/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 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

  1. BOUNDED rounds — never exceed --max-rounds (default 3) — each round costs codex quota; report remaining findings instead of looping on
  2. Verify BEFORE re-reviewmix compile --warnings-as-errors + tests must pass before burning a codex round on broken code
  3. NEVER commit or push — leave git to the user
  4. Codex findings get Iron Law scrutiny — decline suggestions that violate an Iron Law, with explanation in the round report
  5. Skipped findings are reported, never dropped — every finding ends as fixed, declined (with reason), or deferred-by-user
  6. 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 · 130 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.

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. 2d ago First seen · 130 lines · 55 tokens per session scan A 3342ff32ae7d

Subscribe to this mod's changes

phx-codex-loop is a skill published in the GitHub repository oliver-kriska/claude-elixir-phoenix (538 stars, last pushed today), licensed MIT. It adds 55 tokens to every session and 1,362 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to codex-loop, differing in 40 lines, and is treated as a copy.

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