nanzi-ai-agent-platform: Skill for Codex

.agent/skills/writing-skills/SKILL.md

writing-skills is a skill for Codex from RandyChen1985/nanzi-ai-agent-platform. It costs 20 tokens per session (5,015 once invoked), scanned A, a copy of writing-skills, MIT.

A reference guide for creating, editing, and checking agent skills. It applies test-driven development, or TDD—a method of writing tests before implementation—to process documentation by testing whether agents follow the instructions.

In plain words
What is it for?
It is for writing skill documents, creating pressure-based test cases, checking baseline agent behavior, and refining instructions.
Why use it?
It helps reveal unclear instructions and missing rules before a skill is deployed.

Skill for Codex

Written for Codex: reads ~/.codex or $CODEX_HOME. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions subagents.

This is RandyChen1985/nanzi-ai-agent-platform's own configuration. It tells Codex how to work on nanzi-ai-agent-platform itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything nanzi-ai-agent-platform configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is ./render-graphs.js ../some-skill # Each diagram separately.

Reuse

Borrowing it

Nothing to install: this file belongs to RandyChen1985/nanzi-ai-agent-platform. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/RandyChen1985/nanzi-ai-agent-platform/main/.agent/skills/writing-skills/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/RandyChen1985/nanzi-ai-agent-platform

Made for: 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-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/randychen1985/nanzi-ai-agent-platform/writing-skills/github.svg)](https://agentmods.dev/skills/randychen1985/nanzi-ai-agent-platform/writing-skills)
Your own site
<a href="https://agentmods.dev/skills/randychen1985/nanzi-ai-agent-platform/writing-skills"><img src="https://agentmods.dev/badge/skills/randychen1985/nanzi-ai-agent-platform/writing-skills/github.svg" alt="Measured on agentmods" height="20"></a>

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.

agentmods 80×15 button for writing-skills

Your own site · 80×15
<a href="https://agentmods.dev/skills/randychen1985/nanzi-ai-agent-platform/writing-skills"><img src="https://agentmods.dev/badge/skills/randychen1985/nanzi-ai-agent-platform/writing-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,015 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 77% 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 $0.00020 $0.05015
Opus 5 $0.00010 $0.02508
Sonnet 5 $0.00004 $0.01003
Haiku 4.5 $0.00002 $0.00502

Measured 12d ago against content hash 6ffe287552c1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

writing-skills 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 12d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (render-graphs.js), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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

77% identical to writing-skills — 84 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.

.agent/skills/writing-skills/SKILL.md · 656 lines

How it starts

The opening of the file, as written. The whole thing — 656 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Writing Skills

Overview

Writing skills IS Test-Driven Development applied to process documentation.

Personal skills live in agent-specific directories (~/.claude/skills for Claude Code, ~/.codex/skills for Codex)

You write test cases (pressure scenarios with subagents), watch them fail (baseline behavior), write the skill (documentation), watch tests pass (agents comply), and refactor (close loopholes).

Core principle: If you didn't watch an agent fail without the skill, you don't know if the skill teaches the right thing.

REQUIRED BACKGROUND: You MUST understand superpowers:test-driven-development before using this skill. That skill defines the fundamental RED-GREEN-REFACTOR cycle. This skill adapts TDD to documentation.

Official guidance: For Anthropic's official skill authoring best practices, see anthropic-best-practices.md. This document provides additional patterns and guidelines that complement the TDD-focused approach in this skill.

What is a Skill?

A skill is a reference guide for proven techniques, patterns, or tools. Skills help future Claude instances find and apply effective approaches.

Skills are: Reusable techniques, patterns, tools, reference guides

Skills are NOT: Narratives about how you solved a problem once

TDD Mapping for Skills

TDD Concept Skill Creation
Test case Pressure scenario with subagent
Production code Skill document (SKILL.md)
Test fails (RED) Agent violates rule without skill (baseline)
Test passes (GREEN) Agent complies with skill present
Refactor Close loopholes while maintaining compliance
Write test first Run baseline scenario BEFORE writing skill
Watch it fail Document exact rationalizations agent uses
Minimal code Write skill addressing those specific violations
Watch it pass Verify agent now complies
Refactor cycle Find new rationalizations → plug → re-verify

Read the full file on GitHub · 656 lines

Files

What ships with it

6 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. 12d ago First seen · 656 lines · 20 tokens per session scan A 6ffe287552c1

Subscribe to this mod's changes

writing-skills is a skill published in the GitHub repository RandyChen1985/nanzi-ai-agent-platform (167 stars, last pushed yesterday), licensed MIT. It adds 20 tokens to every session and 5,015 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 77% identical to writing-skills, differing in 84 lines, and is treated as a copy.