Agent skill

Codex Brainstorm

Adversarial brainstorming via Claude+Codex debate. An agent skill from sd0xdev/sd0x-harness.

Install Codex Brainstorm

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/codex-brainstorm .claude/skills/codex-brainstorm && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .claude/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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

$skill-installer install https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm

Type 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.

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/codex-brainstorm .agents/skills/codex-brainstorm && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .agents/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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.

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/codex-brainstorm .cursor/skills/codex-brainstorm && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .cursor/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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

$ gemini skills install https://github.com/sd0xdev/sd0x-harness.git --path skills/codex-brainstorm

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/codex-brainstorm .gemini/skills/codex-brainstorm && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .gemini/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm

Installs 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).

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/codex-brainstorm .github/skills/codex-brainstorm && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .github/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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.

skills CLI

$ npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install sd0xdev/sd0x-harness codex-brainstorm --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/codex-brainstorm .opencode/skills/codex-brainstorm && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "codex-brainstorm" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/codex-brainstorm into .opencode/skills/codex-brainstorm/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "codex-brainstorm", 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-brainstorm
GitHub stars: 192
Token cost: ~1.2k tokens
SKILL.md length: 390 words
Files: 4 (incl. references)
Skills in repo: 89
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Adversarial brainstorming via Claude+Codex debate. An agent skill from sd0xdev/sd0x-harness.

Works in 2 steps: Codex Independent Research (Critical) → Adversarial Debate
: exploring solutions
SKILL.md covers Trigger, When NOT to Use, Core Principle and Workflow, plus 7 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Codex Brainstorm is an agent skill from sd0xdev/sd0x-harness. Adversarial brainstorming via Claude+Codex debate. Use when: exploring solutions, feasibility analysis, exhaustive enumeration. Not for: implementation (use feature-dev), architecture only (use codex-architect). Output: Nash equilibrium consensus + action items.

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 4 other files, including reference files (for example `references/equilibrium.md`, `references/techniques.md` and `references/templates.md`).

It sits in Agent Workflows, covering Brainstorming. The repository describes itself as: The harness layer for Claude Code — a reference implementation of harness engineering with hook-enforced dual review, state-machine gates that survive context compaction, and… The licence is MIT.

When your agent uses it

: exploring solutions
Feasibility analysis
Exhaustive enumeration

Example prompts

“/codex-brainstorm”

Requirements

Pre-approved tools (allowed-tools): Read, Grep, Glob, Bash(ls:*), Bash(find:*), Bash(node:*), Write

Workflow steps

2 steps, taken from the step headings in SKILL.md.

Codex Independent Research (Critical)
Adversarial Debate

What it can do on your machine

Read from SKILL.md and the folder at commit a4d4bc1. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Read
- Grep
- Glob
- Bash(ls:*)
- Bash(find:*)
- Bash(node:*)
- Write
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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 Brainstorm loads about 1.2k tokens when it runs, and up to ~4.1k if it reads all its reference files. Until then it costs about 70 tokens; SKILL.md has 390 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~70
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~4.1k

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); files beside SKILL.md are not scanned.

SKILL.md

The full file from sd0xdev/sd0x-harness at commit a4d4bc1, republished under its MIT licence (© sd0xdev). 390 words, ~1,209 tokens.

Download SKILL.mdSave it as .claude/skills/codex-brainstorm/SKILL.md (or your agent's skills folder). This skill also uses 3 other files; get the full folder from GitHub.

name: codex-brainstorm
description: Adversarial brainstorming via Claude+Codex debate. Use when: exploring solutions, feasibility analysis, exhaustive enumeration. Not for: implementation (use feature-dev), architecture only (use codex-architect). Output: Nash equilibrium consensus + action items.
allowed-tools: Read, Grep, Glob, Bash(ls:*), Bash(find:*), Bash(node:*), Write

Codex Brainstorm Skill

Trigger

Keywords: brainstorm, exhaust possibilities, explore solutions, deep discussion, feasibility analysis, solution exploration, Nash equilibrium

When NOT to Use

Simple technical Q&A (answer directly)
Already have a clear solution (implement directly)
Only need code review (use /codex-review)

Core Principle

⚠️ Independent Research → Adversarial Debate → Nash Equilibrium ⚠️

Nash Equilibrium = Neither party can unilaterally change strategy to achieve a better outcome

Workflow

Phase	Action	Output
1	Claude independent research + analysis, forms Position A	Claude's optimal hypothesis
2	Codex independent research + analysis, forms Position B	Codex's optimal hypothesis
3	Multi-round adversarial debate, mutual attacks	Debate exchange record
4	Check equilibrium, no further improvements possible	Equilibrium or divergence
5	Output final report	Nash Equilibrium report

Phase 2: Codex Independent Research (Critical)

⚠️ Must let Codex research independently; do NOT feed Claude's analysis results ⚠️

Dispatch this body per @skills/codex-code-review/references/codex-transport.md § Start — a fresh thread for Phase 2. The transport pins the sandbox and the approval policy, so nothing is chosen here. Save the returned threadId; the Phase 3 debate rounds continue that same thread per its § Resume (references/techniques.md). Bind every placeholder before writing prompt.md — nothing evaluates an expression in a body-only template.

You are a senior architect. Conduct an independent analysis of the following topic.

Topic

${TOPIC}

Constraints

${CONSTRAINTS}

⚠️ Important: You must research independently ⚠️

Before forming conclusions, you must first:

Discover the directory structure: ls at the repository root, then list the directories it actually shows — do not assume a src/ or test/unit/ layout; many repositories, this one included, have neither
Search related code: grep -rn "keyword" . -l | head -10 — rooted at the repository, or at a directory the discovery step above actually surfaced; never at an assumed src/
Read relevant files to confirm existing implementations

Show full SKILL.md (125 more words)Show less

Output Requirements

Research summary (related modules, existing patterns)
Your position + supporting arguments
Potential risks

Phase 3: Adversarial Debate

Structure per round:

Claude attacks flaws in Codex's proposal
Codex rebuts or updates position
Equilibrium check: Can either side raise new attacks?

Termination Conditions

Condition	Description	Result
Nash Equilibrium	Neither side can raise new attacks	Output equilibrium
Convergence	Both positions converge	Output consensus
Max rounds	5 rounds reached with remaining divergence	Output divergence report

Verification

Claude formed an independent position (not following Codex)
Codex performed code research (not speculating)
At least 3 rounds of adversarial debate
Each round has clear attack/defense records
Final report indicates equilibrium status

References

File	Purpose
`references/templates.md`	Claude/debate/report templates
`references/techniques.md`	Attack/defense techniques
`references/equilibrium.md`	Equilibrium determination flow

Example

Input: What implementation approaches are available for this requirement?

Phase 1: Claude independent research → Position A (Solution X is optimal)
Phase 2: Codex independent research → Position B (Solution Y is optimal)
Phase 3: Adversarial debate
  - R1: Claude attacks Y's scalability / Codex attacks X's complexity
  - R2: Claude rebuts / Codex concedes and updates position
  - R3: Both converge to Solution Z, no further attacks → Equilibrium
Phase 4: Output Nash Equilibrium = Solution Z

Files

SKILL.md and 3 other files (references) in skills/codex-brainstorm of sd0xdev/sd0x-harness.

SKILL.md
references/equilibrium.md
references/techniques.md
references/templates.md

Open the folder on GitHubat commit a4d4bc1

Compare with similar skills

Codex Brainstorm 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.

Codex Brainstorm compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Codex Brainstorm this skillsd0xdev/sd0x-harness	192	—	~1.2k	Automated safety check: Pass	MIT	today
Brainstormingxpinjection/test-driven-spring-boot	112	54 repos	~2.6k	Automated safety check: Pass	MIT	1 mo ago
LLM Councilgcpdev/llm-council-skill	461	1 repos	~1k	Automated safety check: Notes	MIT	9 mo ago
Typesafe AIOpenAgentsInc/openagents	455	9 repos	~2.5k	Automated safety check: Pass	MIT	today
Yao Meta Skillyaojingang/yao-meta-skill	2.7k	—	~768	Automated safety check: Pass	MIT	1 mo ago
Trellis StartROYIANS/foliq-print-template-designer	135	6 repos	~646	Automated safety check: Pass	MIT	1 mo ago

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Questions about Codex Brainstorm

What does Codex Brainstorm do?

Adversarial brainstorming via Claude+Codex debate. An agent skill from sd0xdev/sd0x-harness. Codex Brainstorm is an agent skill from sd0xdev/sd0x-harness. Adversarial brainstorming via Claude+Codex debate.

When should I use Codex Brainstorm?

Codex Brainstorm fits situations like: : exploring solutions; feasibility analysis; exhaustive enumeration.

How do I install Codex Brainstorm in Claude Code?

Run `npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a claude-code`. Or copy the skill folder (skills/codex-brainstorm in sd0xdev/sd0x-harness) into .claude/skills/codex-brainstorm in your project. Claude Code loads it when a task matches its description.

How do I install Codex Brainstorm in Codex?

Run `npx skills add sd0xdev/sd0x-harness --skill codex-brainstorm -a codex`. Or copy the skill folder (skills/codex-brainstorm in sd0xdev/sd0x-harness) into .agents/skills/codex-brainstorm in your project. Codex loads it when a task matches its description.

Can I use Codex Brainstorm 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 sd0xdev/sd0x-harness --skill codex-brainstorm -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-brainstorm, .gemini/skills/codex-brainstorm, .github/skills/codex-brainstorm and .opencode/skills/codex-brainstorm in your project.

What does Codex Brainstorm need to run?

SKILL.md names no scripts, command-line tools or credentials: Codex Brainstorm is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Grep, Glob, Bash(ls:*), Bash(find:*), Bash(node:*), Write.

Does Codex Brainstorm access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Codex Brainstorm 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. Review the folder before installing.

What licence does Codex Brainstorm use?

Codex Brainstorm 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 Brainstorm use?

About 1.2k tokens (SKILL.md is roughly 4.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.9k tokens, read only when the agent opens those files.

What are the alternatives to Codex Brainstorm?

Skills that share tags, products or a category with Codex Brainstorm: Brainstorming (xpinjection/test-driven-spring-boot, 112 stars), LLM Council (gcpdev/llm-council-skill, 461 stars), Typesafe AI (OpenAgentsInc/openagents, 455 stars) and Yao Meta Skill (yaojingang/yao-meta-skill, 2.7k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Codex Brainstorm?

sd0xdev (a GitHub user) maintains it in sd0xdev/sd0x-harness, which has 192 GitHub stars. The repository holds 89 skills in this directory. The repository was last updated on October 8, 2026.

Source: sd0xdev/sd0x-harness on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Codex Brainstorm

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Codex Brainstorm Skill

Trigger

When NOT to Use

Core Principle

Workflow

Phase 2: Codex Independent Research (Critical)

Topic

Constraints

⚠️ Important: You must research independently ⚠️

Output Requirements

Phase 3: Adversarial Debate

Termination Conditions

Verification

References

Example

Files

Compare with similar skills

Similar skills

More from sd0xdev/sd0x-harness

Related

Questions about Codex Brainstorm