Claude Code Agent Development
anthropics/claude-plugins-official
Explains how to write agents for Claude Code plugins: the markdown file with YAML frontmatter, trigger descriptions, model and color settings, and system prompt design.
Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context.
Install Subagent Fanout
$ npx skills add Archive228/loopkit --skill subagent-fanout -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install Archive228/loopkit subagent-fanout --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/Archive228/loopkit.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/subagent-fanout .claude/skills/subagent-fanout && 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 "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .claude/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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/Archive228/loopkit/tree/main/skills/subagent-fanoutType 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 Archive228/loopkit --skill subagent-fanout -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install Archive228/loopkit subagent-fanout --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Archive228/loopkit.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/subagent-fanout .agents/skills/subagent-fanout && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .agents/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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 Archive228/loopkit --skill subagent-fanout -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install Archive228/loopkit subagent-fanout --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Archive228/loopkit.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/subagent-fanout .cursor/skills/subagent-fanout && 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 "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .cursor/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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/Archive228/loopkit.git --path skills/subagent-fanout--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 Archive228/loopkit --skill subagent-fanout -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install Archive228/loopkit subagent-fanout --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Archive228/loopkit.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/subagent-fanout .gemini/skills/subagent-fanout && 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 "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .gemini/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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 Archive228/loopkit subagent-fanoutInstalls 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 Archive228/loopkit --skill subagent-fanout -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/Archive228/loopkit.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/subagent-fanout .github/skills/subagent-fanout && 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 "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .github/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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 Archive228/loopkit --skill subagent-fanout -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install Archive228/loopkit subagent-fanout --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Archive228/loopkit.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/subagent-fanout .opencode/skills/subagent-fanout && 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 "subagent-fanout" agent skill from https://github.com/Archive228/loopkit/tree/main/skills/subagent-fanout into .opencode/skills/subagent-fanout/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "subagent-fanout", 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
subagent-fanout- GitHub stars
- 755
- Token cost
- ~230 tokens
- SKILL.md length
- 97 words
- Files
- 1
- Skills in repo
- 43
- Repo updated
- First seen
- Licence
- MIT
At a glance
Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context.
- A goal branches into many independent pieces
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Tasks that involve Subagents
What it does
Subagent Fanout is an agent skill from Archive228/loopkit. Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context. Use when a goal branches into many independent pieces.
Its SKILL.md is about 230 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, covering Subagents. The repository describes itself as: 33 battle-tested skills + minimal .claude harness for any coding agent (Claude Code, Cursor, Codex, Gemini CLI). The licence is MIT.
When your agent uses it
- A goal branches into many independent pieces
- Tasks that involve Subagents
Example prompts
- “/subagent-fanout”
What it can do on your machine
Read from SKILL.md and the folder at commit 5ae033e. 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
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
Subagent Fanout loads about 230 tokens when it runs. Until then it costs about 42 tokens; SKILL.md has 97 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 Archive228/loopkit at commit 5ae033e, republished under its MIT licence (© Archive228). 97 words, ~230 tokens.
Download SKILL.mdSave it as
.claude/skills/subagent-fanout/SKILL.md (or your agent's skills folder).- name
- subagent-fanout
- description
- Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context. Use when a goal branches into many independent pieces.
- when_to_use
- analyze N items, fix M files, search K sources, anything embarrassingly parallel
Subagent Fan-out
One context loaded with ten jobs' worth of material is the exact shape that triggers context rot. Ten small contexts don't.
- Spawn one subagent per independent unit (one file, one source, one check). Each gets a fresh context window.
- An orchestrator synthesizes their results — it never does the per-unit work itself.
- Give each worker a tight role and only the input it needs.
- Use ONLY when the pieces are genuinely independent. Sequential dependencies stay in one chain. Fan-out for breadth (research, multi-file edits, multi-source verification). Keep it serial when step N needs step N-1's output.
© Archive228, 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 skills/subagent-fanout of Archive228/loopkit.
Open the folder on GitHubat commit 5ae033e
Compare with similar skills
Subagent Fanout 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 |
|---|---|---|---|---|---|---|
| Subagent Fanout this skillArchive228/loopkit | 755 | — | ~230 | Automated safety check: Pass | MIT | |
| Claude Code Agent Developmentanthropics/claude-plugins-official | 38k | 7 repos | ~2.8k | Automated safety check: Pass | Apache-2.0 | |
| Subagent Driven DevelopmentAsvarox/allkaraoke | 261 | 37 repos | ~1.2k | Automated safety check: Pass | None | |
| Dispatching Parallel Agentsultralisp/ultralisp | 258 | 40 repos | ~1.5k | Automated safety check: Pass | None | |
| Paseo Advisor Second Opiniongetpaseo/paseo | 20k | 1 repos | ~756 | Automated safety check: Pass | Custom licence | |
| Task Observerrebelytics/one-skill-to-rule-them-all | 3.2k | 1 repos | ~11k | Automated safety check: Pass | CC-BY-4.0 |
Similar skills
- Official
Subagent Driven Development
Asvarox/allkaraoke
A skill your agent uses when executing implementation plans with independent tasks in the current session
Dispatching Parallel Agents
ultralisp/ultralisp
A skill your agent uses when facing 2+ independent tasks that can be worked on without shared state or sequential dependencies
Paseo Advisor Second Opinion
getpaseo/paseo
Launches one separate agent through Paseo to give a second opinion on the current task, with a self-contained briefing and no permission to edit files.
Task Observer
rebelytics/one-skill-to-rule-them-all
Monitors task execution for skill improvement opportunities.
O2 Review Loop
openobserve/openobserve
Splits a change into planner, coder and independent reviewer roles: you confirm a spec, a subagent implements it, and a separate reviewer checks each round's local WIP commit.
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Related
Categories
Questions about Subagent Fanout
What does Subagent Fanout do?
Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context. Subagent Fanout is an agent skill from Archive228/loopkit. Parallelize independent sub-jobs across fresh-context subagents instead of one bloated context.
When should I use Subagent Fanout?
Subagent Fanout fits situations like: A goal branches into many independent pieces; tasks that involve Subagents.
How do I install Subagent Fanout in Claude Code?
Run `npx skills add Archive228/loopkit --skill subagent-fanout -a claude-code`. Or copy the skill folder (skills/subagent-fanout in Archive228/loopkit) into .claude/skills/subagent-fanout in your project. Claude Code loads it when a task matches its description.
How do I install Subagent Fanout in Codex?
Run `npx skills add Archive228/loopkit --skill subagent-fanout -a codex`. Or copy the skill folder (skills/subagent-fanout in Archive228/loopkit) into .agents/skills/subagent-fanout in your project. Codex loads it when a task matches its description.
Can I use Subagent Fanout 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 Archive228/loopkit --skill subagent-fanout -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/subagent-fanout, .gemini/skills/subagent-fanout, .github/skills/subagent-fanout and .opencode/skills/subagent-fanout in your project.
What does Subagent Fanout need to run?
SKILL.md names no scripts, command-line tools or credentials: Subagent Fanout is instructions for the agent only.
Does Subagent Fanout 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 Subagent Fanout 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 Subagent Fanout use?
Subagent Fanout 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 Subagent Fanout use?
About 230 tokens (SKILL.md is roughly 920 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 Subagent Fanout?
Skills that share tags, products or a category with Subagent Fanout: Claude Code Agent Development (anthropics/claude-plugins-official, 38k stars), Subagent Driven Development (Asvarox/allkaraoke, 261 stars), Dispatching Parallel Agents (ultralisp/ultralisp, 258 stars) and Paseo Advisor Second Opinion (getpaseo/paseo, 20k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Subagent Fanout?
Archive228 (a GitHub user) maintains it in Archive228/loopkit, which has 755 GitHub stars. The repository holds 43 skills in this directory. The repository was last updated on July 14, 2026.
Source: Archive228/loopkit on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.