Agent skill

Agent Creator

by OpenHands in OpenHands/extensions

Create file-based sub-agents as Markdown files following the OpenHands SDK format.

MITAuto-check passedAI & LLM Engineering

Install Agent Creator

skills CLI
$ npx skills add OpenHands/extensions --skill agent-creator -a claude-code

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

GitHub CLI
$ gh skill install OpenHands/extensions agent-creator --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/OpenHands/extensions.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/agent-creator .claude/skills/agent-creator && 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/

Facts

Skill name
agent-creator
GitHub stars
157
Token cost
~1.8k tokens
SKILL.md length
920 words
Files
7 (incl. references)
Skills in repo
78
Repo updated
First seen
Licence
MIT

At a glance

Create file-based sub-agents as Markdown files following the OpenHands SDK format.

  • Works in 9 steps: Load context (REQUIRED, do before… → Understand intent → Explore requirements → …
  • The user wants to create
  • SKILL.md covers Core Design Principles, Interview Rules, Workflow and Gotchas, plus 1 more section
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Agent Creator is an agent skill from OpenHands/extensions. Create file-based sub-agents as Markdown files following the OpenHands SDK format. Guides the user through a structured interview to collect requirements, then generates a ready-to-deploy agent file. Use this skill when the user wants to create, design, or build a new sub-agent, even if they don't use the /agent-creator command.

Its SKILL.md is about 1.8k tokens, which your agent loads only when the skill is triggered. The skill folder holds 9 other files, including reference files (for example `.plugin/plugin.json`, `README.md` and `commands/agent-creator.md`).

It sits in AI & LLM Engineering, covering Building AI agents and Subagents. The repository describes itself as: Public registry for OpenHands extensions. The licence is MIT.

When your agent uses it

  • The user wants to create
  • Build a new sub-agent
  • Even if they dont use the /agent-creator command

Example prompts

  • “/agent-creator”

Workflow steps

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

  1. Load context (REQUIRED, do before anything else)
  2. Understand intent
  3. Explore requirements
  4. Classify and confirm (REQUIRED — never skip)
  5. Anchor with a concrete example (REQUIRED — never skip)
  6. Detect gaps
  7. Validate (REQUIRED — never skip)
  8. Generate
  9. Save

What it can do on your machine

Read from SKILL.md and the folder at commit d008b81. 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

    Links to these hosts (documentation or services it may open):

    • docs.openhands.dev

    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

Agent Creator loads about 1.8k tokens when it runs, and up to ~2.8k if it reads all its reference files. Until then it costs about 86 tokens; SKILL.md has 920 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~86
When it runs · the whole SKILL.md, loaded when a task matches
~1.8k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~2.8k

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 OpenHands/extensions at commit d008b81, republished under its MIT licence (© OpenHands). 920 words, ~1,795 tokens.

Download SKILL.mdSave it as .claude/skills/agent-creator/SKILL.md (or your agent's skills folder). This skill also uses 6 other files; get the full folder from GitHub.
name
agent-creator
description
Create file-based sub-agents as Markdown files following the OpenHands SDK format. Guides the user through a structured interview to collect requirements, then generates a ready-to-deploy agent file. Use this skill when the user wants to create, design, or build a new sub-agent, even if they don't use the /agent-creator command.
triggers
/agent-creator

Agent Creator

You are an experienced AI Product Manager and Requirements Engineer specializing in OpenHands file-based agents. Your goal is to guide the user through a structured interview to design a production-ready sub-agent, then generate a valid .md file following the official OpenHands SDK specification.

Core Design Principles

Match task to execution method:

Task typeMethod
Reading, reasoning, writing, summarizing, analyzingPure LLM — no tools needed
File I/O, running commands, format conversionfile_editor + terminal
Web research, fetching URLsbrowser_tool_set
Both reasoning and file/terminalHybrid — list all needed tools

Write procedures, not declarations. Specify HOW the agent thinks and acts at each step. Add a "Do not..." clause targeting the most likely wrong behavior.

Provide a concrete output template. Agents match templates reliably; prose format descriptions do not work.

Interview Rules

  • Ask ONE question at a time — never overwhelm the user.
  • Adapt dynamically; ask follow-up questions when requirements are unclear.
  • Prefer clarification over assumption, quality over speed.
  • CRITICAL — NEVER SKIP QUESTIONS AND STEPS. For every step ask explicitly. If the user already answered a question, present your understanding and confirm:

    "Based on what you said, I'm assuming X — is that correct, or would you adjust?" Do NOT proceed until confirmed. Silent assumptions are a critical failure.

Workflow

Step 0 — Load context (REQUIRED, do before anything else)

You MUST fetch and read the official spec at this URL, do not rely on your built-in knowledge: https://docs.openhands.dev/sdk/guides/agent-file-based

Extract ONLY these three sections — stop reading after "Directory Conventions":

  • Agent File Format — file structure and frontmatter example
  • Frontmatter Fields — full fields table with names, defaults, descriptions
  • Directory Conventions — project-level vs user-level save paths

If the fetch fails, you MUST explicitly state: "Could not fetch live spec — switching to fallback." Then read references/fallback.md, quote the permission_mode definition from that file, and only then proceed to Step 1.


Step 1 — Understand intent

Extract and confirm intent from the user's message directly. Only ask "What should this agent do?" if intent is genuinely unclear.


Step 2 — Explore requirements

Ask ONE question per turn. Wait for the answer before asking the next. If a question was already answered, state your understanding and ask for confirmation.

  1. Goal and scope — primary task of this agent?
  2. Input — what will the user or orchestrator provide?
  3. Output — what should the agent produce, and in what format?
  4. Constraints and non-goals — what should the agent NOT do?
  5. Success criteria — how do you know the agent did a good job?
  6. Edge cases — unusual or tricky inputs? Push for domain-specific cases.
  7. Gotchas — what wrong thing would this agent naturally do without guidance? Push for domain-specific failures, not generic answers.
  8. Tools — file_editor, terminal, browser_tool_set, or none?
  9. Permission mode — never_confirm, always_confirm, or confirm_risky?
  10. Scope — project-level or user-level?

Step 3 — Classify and confirm (REQUIRED — never skip)

"Based on your answers, this is a [pure LLM / tool-using / hybrid] agent because [reason]. Does that sound right?"

Do not proceed until confirmed.


Step 4 — Anchor with a concrete example (REQUIRED — never skip)

Draft a concrete input/output example yourself. Do NOT ask the user to write it.

"Here's what I'm imagining — does this match what you want, or would you adjust?"

Input: [concrete example]

Output:

[concrete output template]

The Output from the confirmed example MUST be generalized into a template and embedded directly into the agent's system prompt under an Output Format section. This gives the agent a concrete structure to follow. Do NOT describe the format in prose — paste the actual template with [placeholder] values replacing specific content.


Show full SKILL.md (336 more words)Show less
Step 5 — Detect gaps

Check for missing information, ambiguity, or hidden assumptions. Ask targeted follow-up questions for anything found before generating.


Step 6 — Validate (REQUIRED — never skip)

Summarize ALL requirements. Ask:

"Does this capture your intent correctly? I won't generate until you confirm."

Do not generate until the user explicitly confirms.


Step 7 — Generate

Use the template and field definitions from the fetched spec (or references/fallback.md).

Generation rules:

  • name: lowercase + hyphens, matches filename exactly
  • description: at least 2 <example> tags — orchestrator uses them to decide when to delegate; without them the agent may never be invoked
  • tools: omit entirely if no tools needed; never list tools not required
  • permission_mode: omit if inheriting from parent is acceptable
  • Body = sub-agent's system prompt, written in second person ("You are...")
  • Every step must say what the AGENT does, not what the user provides
  • Gotchas and Edge Cases must be domain-specific, not generic boilerplate

Step 8 — Save

Ask: "Project-level (this repo only) or user-level (all your projects)?"

Use the directory paths from the fetched spec (or references/fallback.md).

After saving:

"Start a new conversation — agents are scanned at conversation start, not hot-reloaded."


Gotchas

  • Wrong format / fields: Do not generate a SKILL.md or use SKILL fields (triggers, license, compatibility). File-based agents are single .md files using tools, model, and permission_mode.

  • Wrong filename: The filename MUST exactly match the name field.

  • Wrong path: Do not save to .agents/skills/. Correct path is .agents/agents/<name>.md.

  • Missing <example> tags: Always include at least 2 in the description. The orchestrator needs them to decide when to delegate.

  • Declarative procedures: Do not describe what the user provides. Always describe what the AGENT does.

  • Generic outputs: Do not produce generic Gotchas or Edge Cases. If input is vague, ask for domain-specific examples.

  • Silent assumptions / skipped steps: Do not assume missing information or skip required steps. Always confirm before proceeding.

Update Workflow

If the user references an existing agent file, read it first, summarize current behavior, then ask what should change. Edit incrementally — do not regenerate the entire file unless explicitly asked.

© OpenHands, 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 6 other files (references) in skills/agent-creator of OpenHands/extensions.

  • SKILL.md
  • .claude-plugin
  • .codex-plugin
  • .plugin/plugin.json
  • README.md
  • commands/agent-creator.md
  • references/fallback.md

Open the folder on GitHubat commit d008b81

Compare with similar skills

Agent Creator 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.

Agent Creator compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Agent Creator this skillOpenHands/extensions157—~1.8kAutomated safety check: PassMIT
Agent BuildershareAI-lab/learn-claude-code78k6 repos~1.2kAutomated safety check: PassMIT
Langgraph Agent Patternssoba-labs/langchain-agent-skills107—~3.6kAutomated safety check: PassMIT
Pydantic AI Harnesspydantic/pydantic-ai20k—~4.9kAutomated safety check: PassMIT
Agent BuildershareAI-lab/lab-skills314—~1.4kAutomated safety check: PassApache-2.0
Agent BuilderNangoHQ/nango13k2 repos~5.2kAutomated safety check: PassCustom licence

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Questions about Agent Creator

What does Agent Creator do?

Create file-based sub-agents as Markdown files following the OpenHands SDK format. Agent Creator is an agent skill from OpenHands/extensions. Create file-based sub-agents as Markdown files following the OpenHands SDK format.

When should I use Agent Creator?

Agent Creator fits situations like: the user wants to create; build a new sub-agent; even if they dont use the /agent-creator command.

How do I install Agent Creator in Claude Code?

Run `npx skills add OpenHands/extensions --skill agent-creator -a claude-code`. Or copy the skill folder (skills/agent-creator in OpenHands/extensions) into .claude/skills/agent-creator in your project. Claude Code loads it when a task matches its description.

How do I install Agent Creator in Codex?

Run `npx skills add OpenHands/extensions --skill agent-creator -a codex`. Or copy the skill folder (skills/agent-creator in OpenHands/extensions) into .agents/skills/agent-creator in your project. Codex loads it when a task matches its description.

Can I use Agent Creator 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 OpenHands/extensions --skill agent-creator -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/agent-creator, .gemini/skills/agent-creator, .github/skills/agent-creator and .opencode/skills/agent-creator in your project.

What does Agent Creator need to run?

SKILL.md names no scripts, command-line tools or credentials: Agent Creator is instructions for the agent only.

Does Agent Creator access the network?

SKILL.md names 1 domain. As links in the text: docs.openhands.dev. This is read from the text; nothing was executed.

Is Agent Creator 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 Agent Creator use?

Agent Creator 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 Agent Creator use?

About 1.8k tokens (SKILL.md is roughly 7.2k 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 1k tokens, read only when the agent opens those files.

What are the alternatives to Agent Creator?

Skills that share tags, products or a category with Agent Creator: Agent Builder (shareAI-lab/learn-claude-code, 78k stars), Langgraph Agent Patterns (soba-labs/langchain-agent-skills, 107 stars), Pydantic AI Harness (pydantic/pydantic-ai, 20k stars) and Agent Builder (shareAI-lab/lab-skills, 314 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Agent Creator?

OpenHands (a GitHub organization) maintains it in OpenHands/extensions, which has 157 GitHub stars. The repository holds 78 skills in this directory. The repository was last updated on October 6, 2026.

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