writing-plans

writing-plans is a skill for Claude Code, Codex from mateaix/mateclaw. It costs 16 tokens per session (1,719 once invoked), scanned A, a copy of writing-plans, Apache-2.0.

A method for writing detailed implementation plans that break software work into small, testable steps. TDD means writing a failing test before the code that makes it pass.

In plain words
What is it for?
Use it before multi-step features, complex changes, or delegated work to describe the files to edit, code to write, tests to run, documentation to check, and ways to verify the result.
Why use it?
It gives an implementer enough context to work in an unfamiliar codebase and makes assumptions, tests, files, and verification steps explicit.

Skill for Claude CodeCodex

About the project

MateClaw is a pluggable agent runtime that coordinates AI agents, tools, conversations, memory, and workflows. It is designed for personal and multi-user AI assistants, including agents used through chat platforms. Catalogue add-ons provide skills for extending its agent workflows.

mateaix/mateclaw · 1,078 stars · on GitHub · claw.mate.vip

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.

agentmods
npx agentmods add skills/mateaix/mateclaw/writing-plans
Any agent
npx skills add mateaix/mateclaw --skill writing-plans
Clone the repo
git clone --depth 1 https://github.com/mateaix/mateclaw

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 writing-plans

README.md
[![agentmods](https://agentmods.dev/badge/skills/mateaix/mateclaw/writing-plans.svg)](https://agentmods.dev/skills/mateaix/mateclaw/writing-plans)
Your own site
<a href="https://agentmods.dev/skills/mateaix/mateclaw/writing-plans"><img src="https://agentmods.dev/badge/skills/mateaix/mateclaw/writing-plans.svg" alt="Measured on agentmods" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,719 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 94% copy Near-identical to another mod 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 $0.00016 $0.01719
Opus 5 $0.00008 $0.00860
Sonnet 5 $0.00003 $0.00344
Haiku 4.5 $0.00002 $0.00172

Measured 6d ago against content hash 585c6ff26233, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

writing-plans 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.

Origin

This is a copy

94% identical to writing-plans — 21 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

mateclaw-server/src/main/resources/skills/writing-plans/SKILL.md · 297 lines

How it starts

The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Writing Implementation Plans

Overview

Write comprehensive implementation plans assuming the implementer has zero context for the codebase and questionable taste. Document everything they need: which files to touch, complete code, testing commands, docs to check, how to verify. Give them bite-sized tasks. DRY. YAGNI. TDD. Frequent commits.

Assume the implementer is a skilled developer but knows almost nothing about the toolset or problem domain. Assume they don't know good test design very well.

Core principle: A good plan makes implementation obvious. If someone has to guess, the plan is incomplete.

When to Use

Always use before:

  • Implementing multi-step features
  • Breaking down complex requirements
  • Delegating to subagents via subagent-driven-development

Don't skip when:

  • Feature seems simple (assumptions cause bugs)
  • You plan to implement it yourself (future you needs guidance)
  • Working alone (documentation matters)

Bite-Sized Task Granularity

Each task = 2-5 minutes of focused work.

Every step is one action:

  • "Write the failing test" — step
  • "Run it to make sure it fails" — step
  • "Implement the minimal code to make the test pass" — step
  • "Run the tests and make sure they pass" — step
  • "Commit" — step

Too big:

### Task 1: Build authentication system
[50 lines of code across 5 files]

Right size:

### Task 1: Create User model with email field
[10 lines, 1 file]

### Task 2: Add password hash field to User
[8 lines, 1 file]

### Task 3: Create password hashing utility
[15 lines, 1 file]

Plan Document Structure

Header (Required)

Every plan MUST start with:

# [Feature Name] Implementation Plan

> **For the agent:** Use subagent-driven-development skill to implement this plan task-by-task.

**Goal:** [One sentence describing what this builds]

**Architecture:** [2-3 sentences about approach]

**Tech Stack:** [Key technologies/libraries]

---

Task Structure

Read the full file on GitHub · 297 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 · 297 lines · 16 tokens per session scan A 585c6ff26233

Subscribe to this mod's changes

writing-plans is a skill published in the GitHub repository mateaix/mateclaw (1,078 stars, last pushed yesterday), licensed Apache-2.0. It adds 16 tokens to every session and 1,719 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to writing-plans, differing in 21 lines, and is treated as a copy.