plan-frontmatter

plan-frontmatter is a skill for Claude Code from muhimu/claude-plan-lifecycle. It costs 52 tokens per session (1,899 once invoked), scanned A, original, MIT.

Rules for adding plans and design documents to a repository's plans folder. They define required YAML frontmatter, a shared slug for related documents, and how to record the source issue and status.

In plain words
What is it for?
Use them when writing an implementation plan or design document, especially when linking both documents to the same project effort and issue.
Why use it?
They keep planning documents consistent and allow related design and implementation files to be grouped together. This makes the repository's planning tools easier to use.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the plan-lifecycle plugin — 3 skills, 5 commands shipped together

Good fit Use them when writing an implementation plan or design document, especially when…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/muhimu/claude-plan-lifecycle/plan-frontmatter
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add muhimu/claude-plan-lifecycle --skill plan-frontmatter
Clone the repo
git clone --depth 1 https://github.com/muhimu/claude-plan-lifecycle

Made for: Claude Code.

Or install plan-lifecycle, the plugin that ships this one along with the rest of its 3 skills, 5 commands.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for plan-frontmatter

README.md
[![agentmods](https://agentmods.dev/badge/skills/muhimu/claude-plan-lifecycle/plan-frontmatter.svg)](https://agentmods.dev/skills/muhimu/claude-plan-lifecycle/plan-frontmatter)
Your own site
<a href="https://agentmods.dev/skills/muhimu/claude-plan-lifecycle/plan-frontmatter"><img src="https://agentmods.dev/badge/skills/muhimu/claude-plan-lifecycle/plan-frontmatter.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,899 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00052 $0.01899
Opus 5 $0.00026 $0.00949
Sonnet 5 $0.00010 $0.00380
Haiku 4.5 $0.00005 $0.00190

Measured 6d ago against content hash 289631b46a63, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

plan-frontmatter scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/plan-frontmatter/SKILL.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plan Frontmatter

Every plan or design doc written to the plans dir (resolved per the plans-dir convention: PLANS_DIR env, else git config plans.dir, else default local/plans/) starts with YAML frontmatter:

---
title: <human-readable name of the effort>
slug: <kebab-case key, SHARED across all files of one effort>
issue: <root issue — bare number for same-repo, org/repo#N for cross-repo>
status: draft
pr:
---

Fields

  • title — human-readable name. Informational only; no tooling reads it.
  • slug — the grouping key. A design doc and its implementation plan (and any follow-up docs) for the SAME unit of work carry the SAME slug. reap-plans groups files by slug and reaps a whole group together. Pick the slug once (kebab-case, e.g. split-state-enum) and reuse it verbatim on every related file.
  • issue — the root issue the effort addresses. Bare number (issue: 3178) for an issue in the same repo; org/repo#N form for cross-repo. Shared across the slug group like title. Leave empty (issue:) only when the work genuinely traces to no issue. When set, two things follow:
    1. The plan body's header block states the root issue with a one-line mechanism summary — a reader must not need to open GitHub to know what problem the plan solves.
    2. The PR that ships the plan MUST include Closes #<N> (or Closes org/repo#N) on the first line of its body, so the merge auto-closes the issue. For stacked PRs, ONLY the tip PR carries the Closes line — under the squash cascade the tip merges last, so tip-merged ⇔ effort done; an earlier slice must not close the issue prematurely. /execute-plan enforces this when it opens PRs.
  • status — one of draft | in-progress | merged | abandoned. A bare plain scalar — no quotes (status: draft, not status: "draft").
  • pr — the PR number once a PR is opened, as a bare number (pr: 2297) — it is a YAML integer, so no quotes and no #. Leave empty (pr:, parses as null) until then. (reap-plans tolerates a stray quote or leading #, but the clean form is the bare number.)

Read the full file on GitHub · 151 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 151 lines · 52 tokens per session scan A 289631b46a63

Subscribe to this mod's changes

plan-frontmatter is a skill published in the GitHub repository muhimu/claude-plan-lifecycle (2 stars, last pushed 5d ago), licensed MIT. It adds 52 tokens to every session and 1,899 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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