codex

codex is a skill for Claude Code, Codex from rbutera/harness-bridge. It costs 27 tokens per session (574 once invoked), scanned A, original, MIT.

A bridge to OpenAI Codex, an AI coding assistant, for getting a second opinion on code, plans, explanations, performance, and general questions.

In plain words
What is it for?
Use it to review files or diffs, critique implementation plans, explain code, analyse performance, ask coding questions, or implement a fix when explicitly requested.
Why use it?
It gives you another analysis of a change or decision, which can reveal mistakes, unclear reasoning, or performance concerns before you proceed.

Skill for Claude CodeCodex

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/rbutera/harness-bridge/codex
Any agent
npx skills add rbutera/harness-bridge --skill codex
Clone the repo
git clone --depth 1 https://github.com/rbutera/harness-bridge

Made for: Claude Code, 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 codex

README.md
[![agentmods](https://agentmods.dev/badge/skills/rbutera/harness-bridge/codex.svg)](https://agentmods.dev/skills/rbutera/harness-bridge/codex)
Your own site
<a href="https://agentmods.dev/skills/rbutera/harness-bridge/codex"><img src="https://agentmods.dev/badge/skills/rbutera/harness-bridge/codex.svg" alt="Measured on agentmods" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 574 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00027 $0.00574
Opus 5 $0.00014 $0.00287
Sonnet 5 $0.00005 $0.00115
Haiku 4.5 $0.00003 $0.00057

Measured 4d ago against content hash 03b4ef30d786, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 4d 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.

.claude/skills/codex/SKILL.md · 39 lines

What it actually says

You are invoking Codex to get a second opinion. Route the user's request to the most appropriate Codex MCP tool.

Tool Selection

Pick the best tool based on the user's request:

Request Type Tool Key Parameters
Code review, diff review mcp__codex__codex_review_code target (diff range or file), focusAreas
Plan critique mcp__codex__codex_review_plan plan, codebasePath
Explain code mcp__codex__codex_explain_code target (file/function), depth
Performance analysis mcp__codex__codex_plan_perf target, metrics
Implement/fix (writes code) mcp__codex__codex_implement task
General question mcp__codex__codex_query prompt

Instructions

  1. Parse the user's argument to determine the task type
  2. If the user references files, read them first for context
  3. Call the most specific Codex tool — prefer specialized tools over codex_query
  4. Always pass workingDirectory to every tool call
  5. Synthesize the response: summarize key findings, highlight important points, give actionable recommendations
  6. Only use codex_implement if the user explicitly asks Codex to make changes

Examples

  • /codex review my recent changescodex_review_code with target "HEAD~1..HEAD"
  • /codex explain src/lib/exec.tscodex_explain_code with target "src/lib/exec.ts"
  • /codex is my approach to caching correct?codex_query with the question
  • /codex optimize the response parsingcodex_plan_perf with target
  • /codex implement error handling for timeoutscodex_implement with task
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. 4d ago First seen · 39 lines · 27 tokens per session scan A 03b4ef30d786

Subscribe to this mod's changes

codex is a skill published in the GitHub repository rbutera/harness-bridge (1 stars, last pushed 8d ago), licensed MIT. It adds 27 tokens to every session and 574 once invoked, about $0.0001 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 2026-08-31.

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