Agent Frontmatter

ValidatorAgentsOfficial docsSubagent frontmatter fields

Agent files are flat .md files (e.g., .claude/agents/code-reviewer.md). The YAML frontmatter configures the agent; the file body is the system prompt.

Fields

Field	Type	Required	Description
name	string	yes	Lowercase with hyphens, max 64 chars
description	string	yes	Min 10 chars, third-person voice
model	string	no	Alias (sonnet, opus, haiku, inherit) or full model ID (e.g. claude-opus-4-6)
tools	string[]	no	Tool names to allow
disallowedTools	string[]	no	Tool names to disallow
permissionMode	string	no	default, acceptEdits, dontAsk, bypassPermissions, or plan
skills	string[]	no	Skills this agent can use
hooks	object	no	Hooks configuration
memory	string	no	user, project, or local
effort	string	no	low, medium, high, or max
maxTurns	number	no	Maximum agent turns (positive integer)
mcpServers	(string|object)[]	no	MCP server references or inline definitions
color	string	no	blue, cyan, green, yellow, magenta, red, or pink (claudelint extension)
background	boolean	no	Run as background task (default: false)
isolation	string	no	worktree — run in a temporary git worktree

Cross-field validations:

• tools and disallowedTools are mutually exclusive

Example

---
name: code-reviewer
description: Reviews code changes for quality, security, and best practices.
model: sonnet
tools:
  - Read
  - Glob
  - Grep
color: blue
---