Hook Development for Claude Code Plugins
anthropics/claude-plugins-official
Explains how to write Claude Code plugin hooks, both prompt-based checks and bash commands, for events such as PreToolUse, Stop and SessionStart.
Generate a parallel plan via Codex. An agent skill from SnakeO/claude-co-commands.
Install Co Plan
$ npx skills add SnakeO/claude-co-commands --skill co-plan -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install SnakeO/claude-co-commands co-plan --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/SnakeO/claude-co-commands.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .claude/skills/co-plan && 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 "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .claude/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-planType 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 SnakeO/claude-co-commands --skill co-plan -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install SnakeO/claude-co-commands co-plan --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/SnakeO/claude-co-commands.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .agents/skills/co-plan && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .agents/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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 SnakeO/claude-co-commands --skill co-plan -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install SnakeO/claude-co-commands co-plan --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/SnakeO/claude-co-commands.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .cursor/skills/co-plan && 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 "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .cursor/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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/SnakeO/claude-co-commands.git --path plugins/co-commands/skills/co-plan--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 SnakeO/claude-co-commands --skill co-plan -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install SnakeO/claude-co-commands co-plan --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/SnakeO/claude-co-commands.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .gemini/skills/co-plan && 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 "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .gemini/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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 SnakeO/claude-co-commands co-planInstalls 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 SnakeO/claude-co-commands --skill co-plan -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/SnakeO/claude-co-commands.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .github/skills/co-plan && 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 "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .github/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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 SnakeO/claude-co-commands --skill co-plan -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install SnakeO/claude-co-commands co-plan --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/SnakeO/claude-co-commands.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/co-commands/skills/co-plan .opencode/skills/co-plan && 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 "co-plan" agent skill from https://github.com/SnakeO/claude-co-commands/tree/master/plugins/co-commands/skills/co-plan into .opencode/skills/co-plan/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "co-plan", 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
co-plan- GitHub stars
- 148
- Token cost
- ~1.2k tokens
- SKILL.md length
- 551 words
- Files
- 1
- Skills in repo
- 3
- Repo updated
- First seen
- Licence
- MIT
At a glance
Generate a parallel plan via Codex. An agent skill from SnakeO/claude-co-commands.
- Works in 3 steps: Start Codex and Hand It to a Background… → Create Your Own Plan → Retrieve and Compare
- You want an additional planning perspective to compare against your own plan
- SKILL.md covers How Codex Is Reached, Step 1: Start Codex and Hand…, Step 2: Create Your Own Plan and Step 3: Retrieve and Compare, plus 2 more sections
- Calls go, claude and codex
What it does
Co Plan is an agent skill from SnakeO/claude-co-commands. Generate a parallel plan via Codex. Use when you want an additional planning perspective to compare against your own plan. Runs in the background so you can continue working in parallel.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Agent Workflows. It works with Bash. The repository describes itself as: Co- planning, validation, and brainstorming commands for Claude Code via Codex MCP. The licence is MIT.
When your agent uses it
- You want an additional planning perspective to compare against your own plan
Example prompts
- “/co-plan”
Workflow steps
3 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 7c477b2. 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
Shell commands in SKILL.md call:
goclaudecodex
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
Co Plan loads about 1.2k tokens when it runs. Until then it costs about 49 tokens; SKILL.md has 551 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); files beside SKILL.md are not scanned.
SKILL.md
The full file from SnakeO/claude-co-commands at commit 7c477b2, republished under its MIT licence (© SnakeO). 551 words, ~1,160 tokens.
Download SKILL.mdSave it as
.claude/skills/co-plan/SKILL.md (or your agent's skills folder).- name
- co-plan
- description
- Generate a parallel plan via Codex. Use when you want an additional planning perspective to compare against your own plan. Runs in the background so you can continue working in parallel.
Co-Plan: Generate a Parallel Plan via Codex
How Codex Is Reached
Codex runs through its CLI, driven by the helper script scripts/codex-session, which lives two
levels above this skill's base directory: call it as <base directory>/../../scripts/codex-session.
It keeps one Codex conversation per session folder and always runs Codex in its read-only sandbox:
codex-session new <label>makes a session folder and prints its pathcodex-session run <DIR>sends<DIR>/prompt.mdas the first message and waits for the replycodex-session read <DIR>prints Codex's latest replycodex-session reply <DIR>sends a follow-up read from stdin and prints the reply
Shell variables do not survive between Bash calls, so always use the literal folder path.
Step 1: Start Codex and Hand It to a Background Subagent
Create the session and write Codex's first message, in one Bash call:
bash DIR="$(<base directory>/../../scripts/codex-session new co-plan)" && echo "$DIR" cat > "$DIR/prompt.md" <<'CODEX_PROMPT' Create a detailed implementation plan for the following task. Think deeply about architecture, steps, edge cases, and trade-offs, reading the code in the working directory as needed — but do NOT share the plan yet. If you need to ask clarifying questions about the task before planning, ask them now. Otherwise, when your plan is fully formed and ready, respond with exactly: "My plan is ready to present" and nothing else. Wait for my next message before sharing the plan. Task: $ARGUMENTS CODEX_PROMPTSpawn a background subagent (Agent tool with
run_in_background: true) to handle all communication with Codex. Give it the helper path and the folder path, and tell it to:- Run
<helper> run <DIR>in the foreground, with the Bash tool's longest timeout (600000 ms). It can take several minutes. - Run
<helper> read <DIR>. If Codex replied "My plan is ready to present", go to step 4. - If Codex asked clarifying questions instead, answer them using its own judgment and the
code in the working directory, by sending a follow-up (quote the heredoc delimiter):
<helper> reply <DIR> <<'CODEX_PROMPT'…CODEX_PROMPT. Then check the reply again as in step 2. If Codex sent its full plan instead of the ready message, treat it as ready. - Report back only that Codex is ready, the session folder, and how many questions it answered. Do NOT request or repeat Codex's plan; that happens in Step 3.
The subagent handles the back-and-forth so you are free to do your own work. In a non-interactive session (
claude -p), do these steps yourself in the foreground instead: background work is killed when that kind of session ends.- Run
Show full SKILL.md (223 more words)Show less
Step 2: Create Your Own Plan
While the subagent communicates with Codex in the background, create your own independent plan. Do NOT check the Codex result until you have finished your own plan. The entire point is to produce two independent plans and then compare them — reading Codex's plan early defeats this purpose and introduces bias.
Step 3: Retrieve and Compare
Only after your plan is complete, confirm the background subagent has reported that Codex is ready. Then ask Codex for its plan in the same conversation; the command prints it:
<base directory>/../../scripts/codex-session reply <DIR> <<'CODEX_PROMPT'
Go ahead, send the plan.
CODEX_PROMPTIf the subagent reported that Codex did not reply, show the user the error it relayed (it names
the fix, such as codex login) and continue with your own plan alone.
Once the plan arrives:
- Read the Codex plan.
- Compare it against your own plan and look for:
- Approaches you missed
- Simpler alternatives
- Risks or edge cases you overlooked
- Integrate useful ideas into your plan and discard the rest.
Continuing the Conversation
To discuss the plan further, send a follow-up in the same Codex conversation. It prints Codex's answer:
<base directory>/../../scripts/codex-session reply <DIR> <<'CODEX_PROMPT'
your follow-up question or counterpoint
CODEX_PROMPTHow to Treat Responses
Treat Codex responses as coming from a junior developer:
- Never assume suggestions are correct; validate each one yourself.
- You are the lead engineer and have final say.
- Use responses as a starting point, not authoritative answers.
© SnakeO, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in plugins/co-commands/skills/co-plan of SnakeO/claude-co-commands.
Open the folder on GitHubat commit 7c477b2
Compare with similar skills
Co Plan 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 |
|---|---|---|---|---|---|---|
| Co Plan this skillSnakeO/claude-co-commands | 148 | — | ~1.2k | Automated safety check: Pass | MIT | |
| Hook Development for Claude Code Pluginsanthropics/claude-plugins-official | 38k | 11 repos | ~4.1k | Automated safety check: Notes | Apache-2.0 | |
| Plugin Settings Patternanthropics/claude-plugins-official | 38k | 7 repos | ~3k | Automated safety check: Pass | Apache-2.0 | |
| Neat-Freak Knowledge CloseoutKKKKhazix/khazix-skills | 21k | — | ~1.9k | Automated safety check: Pass | MIT | |
| Crush Configurationcharmbracelet/crush | 29k | — | ~3.7k | Automated safety check: Pass | Custom licence | |
| Kimi Code DelegationCherryHQ/cherry-studio | 52k | 1 repos | ~504 | Automated safety check: Pass | AGPL-3.0 |
Similar skills
- Official
- Official
Plugin Settings Pattern
anthropics/claude-plugins-official
Shows how Claude Code plugins keep per-project settings and state in .claude/plugin-name.local.md files with YAML frontmatter and a markdown body.
Neat-Freak Knowledge Closeout
KKKKhazix/khazix-skills
Brings project docs, agent rule files, authorized memory and leftover workspace files back in line with what the code and runtime actually do at the end of a work session.
Crush Configuration
charmbracelet/crush
Explains how to configure the Crush coding agent with crushrc or crush.json, covering providers, models, LSPs, MCP servers, hooks, permissions and config precedence.
Kimi Code Delegation
CherryHQ/cherry-studio
Delegates one bounded repository task to Kimi Code in non-interactive prompt mode and reads back the final result from its JSON event stream.
- Official
Operational Value Designer
github/gh-aw
Designs and verifies a deterministic grader that measures whether a GitHub Agentic Workflow run reached its real-world or repository outcome.
More from SnakeO/claude-co-commands
Co Brainstorm
SnakeO/claude-co-commands
Bounce ideas off Codex. An agent skill from SnakeO/claude-co-commands.
Co Validate
SnakeO/claude-co-commands
Get a staff engineer review of your plan via Codex. An agent skill from SnakeO/claude-co-commands.
Related
Works with
Categories
Questions about Co Plan
What does Co Plan do?
Generate a parallel plan via Codex. An agent skill from SnakeO/claude-co-commands. Co Plan is an agent skill from SnakeO/claude-co-commands. Generate a parallel plan via Codex.
When should I use Co Plan?
Co Plan fits situations like: you want an additional planning perspective to compare against your own plan.
How do I install Co Plan in Claude Code?
Run `npx skills add SnakeO/claude-co-commands --skill co-plan -a claude-code`. Or copy the skill folder (plugins/co-commands/skills/co-plan in SnakeO/claude-co-commands) into .claude/skills/co-plan in your project. Claude Code loads it when a task matches its description.
How do I install Co Plan in Codex?
Run `npx skills add SnakeO/claude-co-commands --skill co-plan -a codex`. Or copy the skill folder (plugins/co-commands/skills/co-plan in SnakeO/claude-co-commands) into .agents/skills/co-plan in your project. Codex loads it when a task matches its description.
Can I use Co Plan 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 SnakeO/claude-co-commands --skill co-plan -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/co-plan, .gemini/skills/co-plan, .github/skills/co-plan and .opencode/skills/co-plan in your project.
What does Co Plan need to run?
Going by SKILL.md and its folder, Co Plan needs the command-line tools its instructions call (go, claude and codex).
Does Co Plan 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 Co Plan 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 Co Plan use?
Co Plan 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 Co Plan use?
About 1.2k tokens (SKILL.md is roughly 4.6k 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 Co Plan?
Skills that share tags, products or a category with Co Plan: Hook Development for Claude Code Plugins (anthropics/claude-plugins-official, 38k stars), Plugin Settings Pattern (anthropics/claude-plugins-official, 38k stars), Neat-Freak Knowledge Closeout (KKKKhazix/khazix-skills, 21k stars) and Crush Configuration (charmbracelet/crush, 29k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Co Plan?
SnakeO (a GitHub user) maintains it in SnakeO/claude-co-commands, which has 148 GitHub stars. The repository holds 3 skills in this directory. The repository was last updated on September 28, 2026.
Source: SnakeO/claude-co-commands on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.