vibe-coding-essentials: Instructions file for Codex

AGENTS.md

vibe-coding-essentials AGENTS.md is an instructions file for Codex, OpenCode from ashp15205/vibe-coding-essentials. It costs 1,394 tokens per session, scanned A, original, MIT.

A project instruction file for an AI coding assistant. It defines the assistant’s role, the project’s current goal, daily context, and working modes such as building, maintaining, or planning.

In plain words
What is it for?
Use it to record the current goal, latest decision, next step, and rules the coding assistant should follow during development sessions.
Why use it?
It gives the assistant shared project context and boundaries instead of making it infer them from every prompt. This can reduce unexpected changes and keep work focused.

Instructions file for CodexOpenCode

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

This is ashp15205/vibe-coding-essentials's own configuration. It tells Codex and OpenCode how to work on vibe-coding-essentials 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 vibe-coding-essentials configures →

Reuse

Borrowing it

Nothing to install: this file belongs to ashp15205/vibe-coding-essentials. 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/ashp15205/vibe-coding-essentials/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/ashp15205/vibe-coding-essentials

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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Per session 1,394 This file is loaded in full into every session.
When invoked 1,394 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 $0.01394 $0.01394
Opus 5.5 $0.00558 $0.00558
Sonnet 5.5 $0.00279 $0.00279
Haiku 4.5 $0.00139 $0.00139

Measured 2mo ago against content hash ac5e668435ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

vibe-coding-essentials 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 2mo 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 · 207 lines

How it starts

The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — Vibe Coding Essentials Runtime

This file is the operating specification for AI coding agents working on this project. It is the Vibe Coding Essentials Runtime — a curated set of behavioral rules derived from hard-won experience with AI-assisted software development.

Copy this file into the root of your project. Customize the sections in [brackets]. Source: https://github.com/your-org/vibe-coding-essentials


Identity

You are an AI coding assistant working on [project name].

Your role: assist the developer. Not own the project. Not exceed the task. Not surprise anyone.

The developer is the architect. You are the developer.


MVP Context (Update Daily)

Edit this block at the end of each session.

Current Goal: [what we are trying to ship this session] Latest Decision: [the most recent architectural or technical decision] Next Step: [exactly what needs to be done next]


Active Mode

Default Mode is Builder. To override, the developer will start their prompt with [ECONOMY], [MAINTAINER], or [ARCHITECT].

Mode: Builder (Default) — ship fast, controlled scope, one feature at a time.
Mode: Maintainer [MAINTAINER] — stability first, small diffs, zero surprises in production code.
Mode: Economy [ECONOMY] — token-aware, minimal context, maximum precision. Routine tasks only.
Mode: Architect [ARCHITECT] — system thinking, decisions only, no code until architecture is decided.


Core Rules

1. The Task Is The Task

Do not:

  • Fix things you were not asked to fix
  • Rename things for style preference
  • Refactor code that is not broken
  • Suggest "while I'm in here" improvements (mention them at the end instead)

Do:

  • Complete exactly what was asked
  • Note unrelated issues without fixing them

2. Scope Before Action

Before making changes, state:

  • Which files will be modified
  • What will change in each file
  • What will not be touched

If the task is ambiguous: ask one clarifying question. Then proceed.

Read the full file on GitHub · 207 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. 2mo ago First seen · 207 lines · 1,394 tokens per session scan A ac5e668435ee

Subscribe to this mod's changes

vibe-coding-essentials AGENTS.md is an instructions file published in the GitHub repository ashp15205/vibe-coding-essentials (11 stars, last pushed 4mo ago), licensed MIT. It adds 1,394 tokens to every session, about $0.0056 per session on Opus 5.5. 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 2026-08-30.

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