codex-first

codex-first is a skill for Claude Code, Codex from Kahtaf/OpenCandle. It costs 19 tokens per session (856 once invoked), scanned A, original, MIT.

A workflow rule for Claude Code sessions that sends hands-on coding tasks to Codex CLI, while Claude handles design, specifications, and review.

In plain words
What is it for?
It routes implementation, refactoring, bug fixes with known reproductions, test writing, CI fixes, dependency updates, scripts, and large codebase reading to Codex. It keeps design decisions, sensitive tools, irreversible actions, and final review in Claude.
Why use it?
It helps use each tool for the work it is intended to handle and avoids sending unsuitable tasks to another coding agent.

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/kahtaf/opencandle/codex-first
Any agent
npx skills add Kahtaf/OpenCandle --skill codex-first
Clone the repo
git clone --depth 1 https://github.com/Kahtaf/OpenCandle

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-first

README.md
[![agentmods](https://agentmods.dev/badge/skills/kahtaf/opencandle/codex-first.svg)](https://agentmods.dev/skills/kahtaf/opencandle/codex-first)
Your own site
<a href="https://agentmods.dev/skills/kahtaf/opencandle/codex-first"><img src="https://agentmods.dev/badge/skills/kahtaf/opencandle/codex-first.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 856 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 $0.00019 $0.00856
Opus 5 $0.00010 $0.00428
Sonnet 5 $0.00004 $0.00171
Haiku 4.5 $0.00002 $0.00086

Measured 4d ago against content hash 77a30a8d750b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codex-first 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.

.agents/skills/codex-first/SKILL.md · 77 lines

How it starts

The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex First

Claude Code sessions only. Codex/other harnesses: skip; never self-delegate.

Rationale: Claude (Fable/Opus) tokens metered + expensive; Codex flat-rate. GPT-5.5+ is usually the better and faster model at writing/implementing code; Claude wins at ergonomics — judgment, design, spec-writing, review, orchestration. So Codex types, Claude thinks and verifies.

Route

Delegate to Codex (default for hands-on work):

  • implementation from a frozen spec; refactors; mechanical migrations
  • bug fixes with known repro; test writing; coverage fills
  • CI fixes, dependency bumps, scripts/tooling
  • bulk codebase exploration where raw reading ≫ the answer

Keep in Claude:

  • design, API design, architecture, naming, UX judgment
  • tasks where writing the spec IS the work (ambiguity = design)
  • tiny edits (~<20 lines, single obvious change) — delegation overhead loses
  • anything needing session tools: MCP (browser/computer-use/chronicle), 1Password, secrets
  • destructive/irreversible ops, releases, pushes, GitHub mutations — Claude-side per git rules
  • review of Codex output — never delegated, never skipped

Mixed task: Claude designs first, freezes spec, delegates build-out. Heuristic: prompt reads as a work order → delegate; writing it forces decisions → design, Claude. Portfolio/multi-repo work: $maintainer-orchestrator instead.

Invoke

Prompt via temp file, never inline quoting:

P=$(mktemp); cat >"$P" <<'EOF'
<goal, repo + key paths, constraints ("don't touch X"), non-goals, proof expected, output shape>
EOF
command codex exec --yolo -C <repo> \
  -c model_reasoning_effort="high" \
  -o /tmp/codex-last.md - <"$P" 2>/dev/null
  • --yolo is the house default; Codex may run commands/tests freely. Keep prompts scoped to the target repo.
  • command codex bypasses the interactive zsh wrapper; if not on PATH: fnm exec --using default -- codex
  • stderr suppressed (thinking noise bloats context); drop 2>/dev/null only to debug a failing run
  • read -o file for the result; don't parse the JSONL stream
  • long runs: Bash run_in_background, read -o file on exit; don't kill quiet runs <30 min
  • parallel independent tasks OK: separate repos/dirs, separate -o files
  • outside a git repo add --skip-git-repo-check

Read the full file on GitHub · 77 lines

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 · 77 lines · 19 tokens per session scan A 77a30a8d750b

Subscribe to this mod's changes

codex-first is a skill published in the GitHub repository Kahtaf/OpenCandle (22 stars, last pushed today), licensed MIT. It adds 19 tokens to every session and 856 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 2026-08-30.

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