claude-piv-skeleton: Instructions file for Codex

AGENTS.md

claude-piv-skeleton AGENTS.md is an instructions file for Codex, OpenCode from plipowczan/claude-piv-skeleton. It costs 864 tokens per session, scanned A, original, MIT.

Repository instructions for an AI development process called PIV: first understand the code, then implement changes, then validate them. They require TDD, or test-driven development, where a failing test is written before the code that makes it pass.

In plain words
What is it for?
Use them when adding or changing code: read the project first, write a failing test, make the smallest change that passes it, then improve the code while keeping tests green.
Why use it?
They prevent changes from being made without understanding the existing project and make tests part of every implementation, including small changes.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions Claude Code; mentions Codex.

This is plipowczan/claude-piv-skeleton's own configuration. It tells Codex and OpenCode how to work on claude-piv-skeleton 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 claude-piv-skeleton configures →

Reuse

Borrowing it

Nothing to install: this file belongs to plipowczan/claude-piv-skeleton. 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/plipowczan/claude-piv-skeleton/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/plipowczan/claude-piv-skeleton

Made for: Codex, OpenCode.

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Per session 864 This file is loaded in full into every session.
When invoked 864 The same file — it is already loaded in full.
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 $0.00864 $0.00864
Opus 5 $0.00432 $0.00432
Sonnet 5 $0.00173 $0.00173
Haiku 4.5 $0.00086 $0.00086

Measured 8d ago against content hash 6baa218b143c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

claude-piv-skeleton AGENTS.md 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 8d 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.

AGENTS.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Universal AI Dev Framework - Agent Instructions

PIV: Prime → Implement → Validate methodology for AI-assisted development

Quick Start

  1. Prime: Understand codebase before changes
  2. Implement: Write tests FIRST (TDD mandatory)
  3. Validate: Run tests, verify quality

TDD Requirements (MANDATORY)

RED → GREEN → REFACTOR - No exceptions.

Phase Action Validation
🔴 RED Write failing test FIRST Test fails
🟢 GREEN Minimal code to pass Test passes
🔵 REFACTOR Improve while green Tests still pass

Rules:

  • ❌ NEVER write code before test
  • ❌ NEVER skip TDD for "simple" code
  • ✅ Test must fail before implementation
  • ✅ Minimal code only - no premature optimization

Code Style

General Principles

  • Understand first: Read existing code before modifying
  • Match patterns: Follow existing codebase conventions
  • Minimal changes: Only change what's necessary
  • Self-documenting: Clear names over comments

DRY (Don't Repeat Yourself)

  • Check for existing implementations before creating new
  • Reuse patterns, don't duplicate logic
  • Single source of truth for each piece of knowledge

KISS (Keep It Simple)

  • Prefer simple over clever solutions
  • Don't over-engineer
  • Avoid premature optimization

Testing Patterns

Given-When-Then Structure

GIVEN: Setup test data and preconditions
WHEN:  Execute the code being tested
THEN:  Verify expected outcomes

Test Requirements

  • Descriptive test names explaining behavior
  • Independent tests (no shared state)
  • Fast execution (< 100ms per unit test)
  • Mock external dependencies

Coverage Goals

  • Critical paths: 90-100%
  • Business logic: 80-90%
  • Overall: 80%+

Git Workflow

Branch Naming

  • feature/feature-name - New features
  • fix/bug-description - Bug fixes
  • docs/update-description - Documentation

Read the full file on GitHub · 153 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. 8d ago First seen · 153 lines · 864 tokens per session scan A 6baa218b143c

Subscribe to this mod's changes

claude-piv-skeleton AGENTS.md is an instructions file published in the GitHub repository plipowczan/claude-piv-skeleton (4 stars, last pushed 7mo ago), licensed MIT. It adds 864 tokens to every session, about $0.0043 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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