Finding Experiments
PostHog/posthog
Resolves a PostHog experiment reference from natural language to a concrete experiment ID by browsing experiment-list (not feature-flag tools), with disambiguation when multiple experiments match.
Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict.
MITAuto-check passed
Install Codex Ab
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-ab --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/codex-ab .claude/skills/codex-ab && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .claude/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-abType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-ab --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/codex-ab .agents/skills/codex-ab && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .agents/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-ab --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/codex-ab .cursor/skills/codex-ab && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .cursor/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/oliver-kriska/claude-elixir-phoenix.git --path .claude/skills/codex-ab--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-ab --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/codex-ab .gemini/skills/codex-ab && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .gemini/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-abInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/codex-ab .github/skills/codex-ab && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .github/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install oliver-kriska/claude-elixir-phoenix codex-ab --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/oliver-kriska/claude-elixir-phoenix.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/codex-ab .opencode/skills/codex-ab && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "codex-ab" agent skill from https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/.claude/skills/codex-ab into .opencode/skills/codex-ab/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-ab", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
codex-ab- GitHub stars
- 565
- Token cost
- ~977 tokens
- SKILL.md length
- 371 words
- Files
- 3 (incl. scripts)
- Skills in repo
- 111
- Repo updated
- First seen
- Licence
- MIT
At a glance
Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict.
- Works in 4 steps: Preflight → Run the A/B (background, ~5 min) → Classify → …
- The branch is fresh
- SKILL.md covers Usage, Iron Laws, Workflow and Integration, plus 1 more section
- Runs Shell scripts from its folder; calls codex, bash and git
What it does
Codex Ab is an agent skill from oliver-kriska/claude-elixir-phoenix. Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict. Use when the branch is fresh, before any codex review runs.
Its SKILL.md is about 980 tokens, which your agent loads only when the skill is triggered. The skill folder holds 3 other files, including scripts (for example `scripts/codex-panel-ab.sh` and `triggers.json`).
The repository describes itself as: Claude Code plugin for Elixir/Phoenix/LiveView — 26 specialist agents, Iron Laws enforcement, and Tidewave MCP integration. Plan features with parallel research agents, execute… The licence is MIT.
When your agent uses it
- The branch is fresh
- Before any codex review runs
Example prompts
- “/codex-ab”
Requirements
- A Bash shell
Workflow steps
4 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 9767a82. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 1 file in scripts/ (Shell), which the agent can run.
Shell commands in SKILL.md call:
codexbashgit
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Codex Ab loads about 977 tokens when it runs. Until then it costs about 63 tokens; SKILL.md has 371 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
The full file from oliver-kriska/claude-elixir-phoenix at commit 9767a82, republished under its MIT licence (© oliver-kriska). 371 words, ~977 tokens.
Download SKILL.mdSave it as
.claude/skills/codex-ab/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.- name
- codex-ab
- description
- Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict. Use when the branch is fresh, before any codex review runs.
- effort
- medium
- argument-hint
- [base-branch]
Codex Panel A/B (contributor instrument — verdict decided)
Answer one question with evidence: do dimension-focused codex passes find
real issues that one holistic codex exec review misses? Runs both on the
same diff, then classifies every focused finding against the holistic pass.
DECIDED 2026-07-10 after 4 runs (2 fresh): panel KILLED. Fresh-only 1 real miss / 1 false positive plus one zero-value run at 4× cost — real misses did not outnumber FPs. Kept as contributor tooling (NOT distributed) for one possible retest: a UI-heavy diff with a single extra liveview-focused pass (2× cost). Scoreboard:
.claude/research/2026-07-03-codex-review-integration.md§7.
Usage
/codex-ab # A/B against main (~5 min, 4 codex runs)
/codex-ab develop # explicit base branchIron Laws
- FRESH DIFF ONLY — ask the user to confirm this branch has NOT been
codex-reviewed yet (cloud or
/phx:codex-loop). A drained diff returns NO FINDINGS everywhere and proves nothing — wasted quota - Verify every REAL MISS in the code before counting it — a focused finding only scores if the issue actually exists at that file:line
- Read ONLY the findings
.mdfiles — streams are diverted to.logfiles; never cat a log into context (10k+ lines each) - Exactly 4 codex runs, never re-run dimensions — bounded quota
- Persist the verdict — an unrecorded experiment is wasted quota
Workflow
Step 1: Preflight
Run command -v codex — missing → STOP with install hint. Then:
git status --shortdirty → warn (codex flags local dirt as findings)- Ask: "Has codex already reviewed this branch (PR review or codex-loop)?" If yes → STOP, explain the fresh-diff requirement (Iron Law 1)
Show full SKILL.md (131 more words)Show less
Step 2: Run the A/B (background, ~5 min)
bash ${CLAUDE_SKILL_DIR}/scripts/codex-panel-ab.sh {base} \
.claude/reviews/codex-ab-$(date +%Y-%m-%d-%H%M)Use run_in_background — it runs 1 holistic codex exec review + 3
focused codex exec workers (security / ecto / liveview) in parallel,
all streams redirected. Do other work or wait; never poll.
Step 3: Classify
Read the 4 findings files (holistic.md, security.md, ecto.md,
liveview.md — small). For EACH focused finding:
| Class | Meaning | Test |
|---|---|---|
| DUPLICATE | Holistic already found it | Same file + same defect |
| REAL MISS | Genuine issue holistic missed | Read the code at file:line — defect confirmed (Iron Law 2) |
| FALSE POSITIVE | Manufactured, pre-existing, or wrong | Code check fails, or issue exists on base branch too |
Step 4: Verdict
Present:
## Codex Panel A/B — {branch} vs {base}
| dimension | findings | duplicate | real miss | false positive |
Holistic-only findings: {n}
Verdict this run: {REAL MISS count} real miss vs {FP count} false positive
Decision rule: build --codex-panel only if real misses outnumber false
positives across 2-3 fresh branches.Write the verdict table to .claude/reviews/codex-ab-{date}/VERDICT.md.
Suggest repeating on the next 1–2 fresh branches before deciding.
Integration
fresh branch → /codex-ab (YOU ARE HERE) → verdict logged
├─ real misses win across runs → build /phx:review --codex-panel
└─ duplicates/FPs win → keep holistic /phx:codex-loop, drop panel idea
└─ OUTCOME 2026-07-10: this branch won — panel droppedReferences
${CLAUDE_SKILL_DIR}/scripts/codex-panel-ab.sh— the 4-run harness- Related:
/phx:codex-loop(holistic fix loop),/phx:review --codex
© oliver-kriska, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 2 other files (scripts) in .claude/skills/codex-ab of oliver-kriska/claude-elixir-phoenix.
- SKILL.md
- scripts/codex-panel-ab.sh
- triggers.json
Open the folder on GitHubat commit 9767a82
Compare with similar skills
Codex Ab next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Codex Ab this skilloliver-kriska/claude-elixir-phoenix | 565 | — | ~977 | Automated safety check: Pass | MIT | |
| Finding ExperimentsPostHog/posthog | 40k | — | ~826 | Automated safety check: Pass | Custom licence | |
| ExperimentsArize-ai/phoenix | 12k | — | ~1.8k | Automated safety check: Pass | Custom licence | |
| Scroll Experiencesickn33/agentic-awesome-skills | 47k | 2 repos | ~534 | Automated safety check: Pass | MIT | |
| Webgl Experiencenexu-io/open-design | 100k | — | ~903 | Automated safety check: Pass | Apache-2.0 | |
| Creating ExperimentsPostHog/posthog | 40k | — | ~2.7k | Automated safety check: Pass | Custom licence |
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Questions about Codex Ab
What does Codex Ab do?
Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict. Codex Ab is an agent skill from oliver-kriska/claude-elixir-phoenix. Run an A/B codex review experiment — holistic codex review vs 3 focused dimension passes (security, ecto, liveview) on the branch diff, classify findings, report a panel-value verdict.
When should I use Codex Ab?
Codex Ab fits situations like: the branch is fresh; before any codex review runs.
How do I install Codex Ab in Claude Code?
Run `npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a claude-code`. Or copy the skill folder (.claude/skills/codex-ab in oliver-kriska/claude-elixir-phoenix) into .claude/skills/codex-ab in your project. Claude Code loads it when a task matches its description.
How do I install Codex Ab in Codex?
Run `npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a codex`. Or copy the skill folder (.claude/skills/codex-ab in oliver-kriska/claude-elixir-phoenix) into .agents/skills/codex-ab in your project. Codex loads it when a task matches its description.
Can I use Codex Ab in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add oliver-kriska/claude-elixir-phoenix --skill codex-ab -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/codex-ab, .gemini/skills/codex-ab, .github/skills/codex-ab and .opencode/skills/codex-ab in your project.
What does Codex Ab need to run?
Going by SKILL.md and its folder, Codex Ab needs a shell for the scripts in its folder and the command-line tools its instructions call (codex, bash and git). Our summary lists: A Bash shell.
Does Codex Ab access the network?
SKILL.md contains no URLs. Its commands use git, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Codex Ab safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Codex Ab use?
Codex Ab is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Codex Ab use?
About 977 tokens (SKILL.md is roughly 3.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Codex Ab?
Skills that share tags, products or a category with Codex Ab: Finding Experiments (PostHog/posthog, 40k stars), Experiments (Arize-ai/phoenix, 12k stars), Scroll Experience (sickn33/agentic-awesome-skills, 47k stars) and Webgl Experience (nexu-io/open-design, 100k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Codex Ab?
oliver-kriska (a GitHub user) maintains it in oliver-kriska/claude-elixir-phoenix, which has 565 GitHub stars. The repository holds 111 skills in this directory. The repository was last updated on October 5, 2026.
Source: oliver-kriska/claude-elixir-phoenix on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.