planning-and-task-breakdown

planning-and-task-breakdown is a skill for Claude Code, Codex from momentmaker/kaijutsu. It costs 81 tokens per session (2,251 once invoked), scanned A, original, MIT.

A method for turning a software specification into a clear list of small, testable tasks. Each task is a vertical slice, meaning it delivers one usable capability across the relevant parts of the system.

In plain words
What is it for?
It is for planning features, writing implementation plans, defining acceptance criteria, and identifying the files or components involved.
Why use it?
Large feature requests can hide missing dependencies, unclear ownership, and untestable work. Breaking them into independently checkable tasks makes implementation easier to follow and verify.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths; mentions subagents; positional $N argument.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is - [ ] Run: `go test ./internal/findings/` — confirm RED.

Good fit It is for planning features, writing implementation plans, defining acceptance criteria, and identifying the files or components involved.

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Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/momentmaker/kaijutsu
agentmods
npx agentmods add skills/momentmaker/kaijutsu/planning-and-task-breakdown

Made for: Claude Code, Codex.

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 planning-and-task-breakdown

README.md
[![agentmods](https://agentmods.dev/badge/skills/momentmaker/kaijutsu/planning-and-task-breakdown/github.svg)](https://agentmods.dev/skills/momentmaker/kaijutsu/planning-and-task-breakdown)
Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/momentmaker/kaijutsu/planning-and-task-breakdown"><img src="https://agentmods.dev/badge/skills/momentmaker/kaijutsu/planning-and-task-breakdown.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,251 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 $0.00081 $0.02251
Opus 5 $0.00041 $0.01125
Sonnet 5 $0.00016 $0.00450
Haiku 4.5 $0.00008 $0.00225

Measured 10d ago against content hash 784f5500efee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

planning-and-task-breakdown 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 10d 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/core/planning-and-task-breakdown/SKILL.md · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Planning + Task Breakdown

Adapted from addyosmani/agent-skills under the MIT License. Copyright (c) Addy Osmani. Plan-doc header template + bite-sized step granularity + file-structure-up-front section adapted from obra/superpowers/skills/writing-plans under MIT. Final review pass migrated to jutsu swarm doc-review (the Phase-2 universal QA gate).

A plan is the bridge between a spec and an implementation. The deliverable is a markdown file with vertical-slice tasks, each individually shippable.

When to invoke

  • A spec exists (see spec-driven-development) and the user wants to start work
  • The user says "what are the steps" / "how do we approach this" / "task list"
  • A change spans >5 files or >500 LOC

Plan document header (every plan must start with this)

# <Feature Name> Implementation Plan

**Spec:** `docs/specs/<spec-file>.md`
**Goal:** <one sentence — what this builds>
**Architecture:** <2-3 sentences — approach + key invariants>
**Tech Stack:** <key libs / frameworks / files>

> **For implementers (human or agent):** execute this plan task-by-task with `subagent-driven-development` (recommended) or `executing-plans` (separate-session mode). Steps use checkbox (`- [ ]`) syntax for tracking.

---

The implementer needs to know WHY before HOW. The header is non-negotiable.

Process

Step 1: Read the spec

Locate the spec file (usually docs/specs/<latest>.md). If no spec exists, refuse — invoke spec-driven-development first.

Step 2: Map the file structure UPFRONT

Before defining slices, list every file the implementation will create or modify and the responsibility of each. Decomposition decisions get locked in here.

## File structure

- `cli/internal/findings/store.go` — SQLite handle + migration loader (NEW)
- `cli/internal/findings/migrations/0001_init.sql` — v1 schema (NEW)
- `cli/internal/findings/store_test.go` — Open / Close / migration idempotency (NEW)
- `cli/internal/cli/swarm.go` — post-FanOut hook (MODIFY ~line 484)

Read the full file on GitHub · 177 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 177 lines · 81 tokens per session scan A 784f5500efee

Subscribe to this mod's changes

planning-and-task-breakdown is a skill published in the GitHub repository momentmaker/kaijutsu (3 stars, last pushed 2mo ago), licensed MIT. It adds 81 tokens to every session and 2,251 once invoked, about $0.0004 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.