task-frontmatter-reader

Task Frontmatter Reader

Thin wrapper around the real script ${CLAUDE_PLUGIN_ROOT}/scripts/fm-read.sh. The script is a deterministic file-parsing pipeline (bash + python3 + jq); this skill exists to give it a name callable via the Skill tool and to document its contract.

Contract

Input: one argument — absolute path to a task folder. Output: a single-line JSON object to stdout. Exit code always 0.

Always-present fields:

• id — local:<folder-name> (URI style)
• kind — one of flat | epic | sub_epic | subtask
• parent — local:<id> or null
• children — array of local:<id> strings
• blocks — array of local:<id> strings
• blocked_by — array of local:<id> strings
• external_ids — object (reserved for future tracker integration; currently {})
• status — draft | in_progress | blocked | completed
• mechanism_hints — array of {approach, status} (status: suggested | required); the optional mechanism-challenge contract (GAP G, references/mechanism-challenge.md). Defaults to [] when absent — read-if-present; the challenge's prose-extraction floor applies otherwise.
• folder — absolute path passed in
• warnings — array of {code, detail} entries

Defensive posture. Never throws, never blocks, never exits non-zero. All error conditions surface as entries in warnings[]. Callers should treat warnings as observations, not failures.

Input state	Resulting warnings
Folder does not exist	folder_missing
Folder exists, task.md missing	task_md_missing
task.md present, no frontmatter block	(none — absence of frontmatter is legitimate; kind defaults to flat)
Frontmatter YAML malformed	malformed_yaml
python3 / yaml unavailable	parser_unavailable

Invocation

Call the script directly via the Bash tool:

"${CLAUDE_PLUGIN_ROOT}/scripts/fm-read.sh" "/absolute/path/to/task/folder"

Parse the JSON output with jq. Example:

OUTPUT=$("${CLAUDE_PLUGIN_ROOT}/scripts/fm-read.sh" "$TASK_DIR")
KIND=$(jq -r '.kind' <<<"$OUTPUT")
WARNINGS=$(jq -c '.warnings' <<<"$OUTPUT")

Why this is a script, not embedded instructions

Earlier drafts of this skill embedded the parser logic in the skill body as bash pseudo-code. A paper-test (2026-04-22) showed this led to pseudo-function references that would force Claude to re-implement helpers each invocation, with the risk of divergent implementations across runs. The script-based design eliminates that class of bug: the implementation is a single file that can be tested once and reused deterministically.

Consumers (v2.0.0+)

• /ai-dev-assistant:migrate-to-epic — preflight kind check
• epic-migrator skill — Step 4 validation of generated frontmatter
• /status, /next, /complete — kind detection for hierarchy-aware rendering

Do NOT

• Do not duplicate the parser logic elsewhere. If another skill needs to read frontmatter, it should call fm-read.sh or source fm-helpers.sh directly (for helper bash functions like fm_read, write_epic_frontmatter, etc.).
• Do not treat a non-empty warnings[] as a blocking error. The contract says warnings are observations.
• Do not write to task.md from this skill. Reading is the sole purpose; migration and phase updates live elsewhere.