Free Claude Code subagent builder
A Claude Code subagent is a Markdown file with YAML front matter. The front matter says when Claude should hand work to it and what it may use; the body is its system prompt. Fill in the form, then save the result as .claude/agents/<name>.md (this project only) or ~/.claude/agents/<name>.md (all your projects). Only name and description are required.
Everything runs in your browser. Nothing you type is sent anywhere.
Your subagent file
Same subagent as --agents JSON
For a one-off session or a script, pass the definition when you launch Claude Code instead of saving a file: claude --agents '<json>'. It isn't saved to disk. color is ignored in this form.
Why a subagent file gets skipped
- No
name, or a name that starts with-, contains:or runs past 256 characters. - A
namebut nodescription. - The opening
---isn't on the very first line, so the file reads as having no front matter. - YAML that doesn't parse, often an unquoted colon in the description. This builder quotes values that need it.
- A misspelled field such as
max_turnsis ignored silently. Multi-word fields are camelCase:maxTurns,disallowedTools,permissionMode.
Claude Code watches both agents folders, so an edit is picked up within seconds. The exception is the first file in a brand-new agents folder: restart the session once so it starts watching that folder. Field rules on this page follow the official subagents docs.
Subagent not loading, or Claude never uses it? See 10 reasons a Claude Code subagent is skipped or ignored.
Want the subagent to follow a repeatable recipe? Build one with the SKILL.md builder and list it under "Preload skills". Want every reply in your main session to sound a certain way instead? That's an output style: build one with the output style builder (subagents ignore output styles, so set a subagent's tone in its own prompt). Unsure whether something belongs in a subagent, a skill, CLAUDE.md or a hook? Read CLAUDE.md vs skills vs hooks: which goes where.
Made by Solo Stack Kits. If you'd rather start from finished examples, the free 3-skill sample has ready-made skills for client follow-ups and meeting notes, and the Solo Consultant Kit adds the full set.