frontmatter

AI Frontmatter Skill

Manage /// ai metadata blocks in source files to track provenance: which files have been human-reviewed, which carry rule references, and which are raw AI output.

Block Format

Inspired by PEP 723 inline metadata. The block uses the file's comment character (CC) as a prefix:

{CC} /// ai
{CC} human-reviewed = false
{CC} access = write
{CC} rules = [".claude/rules/python.md"]  # (Optional. May also be a string.)
{CC} skills = ["ai-frontmatter"]           # (Optional.)
{CC} ///

Where {CC} is # for Python/Shell/YAML, // for JS/TS/Go/Rust/Java/C, etc.

Fields

Field	Type	Required	Default
human-reviewed	bool	yes	false
access	string ("write", "read", "hidden")	no	"write"
rules	string array	no	omitted
skills	string array	no	omitted

• human-reviewed: whether a human has read and approved the file contents.
• rules: paths to rule files (relative to repo root) that the agent should consult when modifying this file.
• skills: skill names that agents must load (if not already loaded) before working in this file.
• access: controls whether AI agents may read or write the file. "write" = full access (read and write), "read" = read-only, "hidden" = no access. If the field is absent, assume "write" – this keeps all existing files fully accessible without needing updates.

Placement

The block is inserted after any shebang or encoding declaration lines, followed by a blank line before the rest of the file content.

Agent Rules

1. MUST NOT set human-reviewed = true. Only humans may do this.
2. Absence of a block means the file is unreviewed (human-reviewed = false) and fully accessible (access = "write").
3. When pattern-matching or learning from existing code, prefer files with human-reviewed = true.
4. When modifying a file that has human-reviewed = true, reset it to false – your edit invalidates the review.
5. When creating new files, stamp them with human-reviewed = false.
6. MUST NOT modify or delete a file with access = "read".
7. MUST NOT read, modify, or delete a file with access = "hidden".
8. MUST NOT relax access (e.g. change "read" → "write"). Only humans may do that.
9. MAY tighten access (e.g. stamp a new file with access = "read").

Authority Hierarchy

When multiple files show different patterns, trust them in this order:

1. human-reviewed = true – highest trust
2. human-reviewed = false with rules – guided AI output
3. human-reviewed = false without rules – raw AI output
4. No block at all – unknown provenance. Notify user so that they can update the frontmatter.

CLI Usage

stamp – Add or update a frontmatter block

${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp <file> \
  [--reviewed true|false] \
  [--rules path1,path2] \
  [--skills skill1,skill2] \
  [--access write|read|hidden] \
  [--comment-char CC]

• --reviewed defaults to false
• --comment-char auto-detected from file extension; use flag to override
• Idempotent: running twice produces the same output
• Replaces existing block if present; inserts after shebang/encoding if not

Examples:

# Stamp a Python file (auto-detects #)
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp libs/internal/foo/bar.py

# Stamp with rules
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp src/main.py \
  --rules .claude/rules/python.md,.claude/rules/trust.md

# Stamp as read-only
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp src/main.py --access read

# Human marks a file as reviewed
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp src/main.py --reviewed true

# Override comment char for an unusual extension
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py stamp config.conf --comment-char "#"

scan – Report frontmatter coverage

${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py scan \
  [--path .] \
  [--ext py,sh,ts,tsx,js,go]

• Uses git ls-files to respect .gitignore
• Groups results by directory
• Shows per-directory and total counts: stamped (reviewed / unreviewed) and unstamped

Examples:

# Scan entire repo for default extensions
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py scan

# Scan only Python files in libs/
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py scan --path libs/ --ext py

# Scan TypeScript files
${CLAUDE_PLUGIN_ROOT}/skills/frontmatter/scripts/frontmatter.py scan --ext ts,tsx

Extension → Comment Character Map

Extensions	CC
py, sh, bash, yaml, yml, toml, r, rb, pl	#
js, ts, tsx, jsx, go, rs, java, c, cpp, h, hpp, cs, swift, kt	//

Special case: Markdown

In Markdown, use YAML frontmatter instead of comments.

ai:
  human-reviewed: true