nj-mmo: Instructions file for Codex

AGENTS.md

nj-mmo AGENTS.md is an instructions file for Codex, OpenCode from tech-leads-club/nj-mmo. It costs 1,182 tokens per session, scanned A, original, MIT.

Project instructions for a browser-based, low-poly 3D multiplayer role-playing game built with a server, client, and shared project repository.

In plain words
What is it for?
Use them when working on the game’s server, client, database, combat rules, testing, or feature phases in its Nx monorepo, a repository containing multiple related projects.
Why use it?
They define where game outcomes are tested, how the client and server should be separated, and which workflow agents must follow when building features.

Instructions file for CodexOpenCode

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

This is tech-leads-club/nj-mmo's own configuration. It tells Codex and OpenCode how to work on nj-mmo 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 nj-mmo configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tech-leads-club/nj-mmo. 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/tech-leads-club/nj-mmo/master/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/tech-leads-club/nj-mmo

Made for: Codex, OpenCode.

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 nj-mmo AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/tech-leads-club/nj-mmo/agents-md/github.svg)](https://agentmods.dev/instructions/tech-leads-club/nj-mmo/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/tech-leads-club/nj-mmo/agents-md"><img src="https://agentmods.dev/badge/instructions/tech-leads-club/nj-mmo/agents-md/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 nj-mmo AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/tech-leads-club/nj-mmo/agents-md"><img src="https://agentmods.dev/badge/instructions/tech-leads-club/nj-mmo/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,182 This file is loaded in full into every session.
When invoked 1,182 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 $0.01182 $0.01182
Opus 5 $0.00591 $0.00591
Sonnet 5 $0.00236 $0.00236
Haiku 4.5 $0.00118 $0.00118

Measured 10d ago against content hash 4b9f9239eb49, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

nj-mmo 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 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.

AGENTS.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Guidance for AI agents working in this repository.

What this project is

A browser-playable, low-poly 3D multiplayer MVP of an MMORPG inspired by L2 — a Talking Island vertical slice. Authoritative Colyseus server, Three.js client, Nx monorepo (server/ + client/), SQLite first.

L2J_Mobius Classic (~/Dev/L2J_Mobius/L2J_Mobius_Classic_1.0) is a reference only: parse its open-source XML data to seed our own DB, and translate combat and game mechanics rules from its .java into TypeScript, don't reinvent the wheel, copy and adapt. Never a dependency, never the real L2 protocol.

How we work

Features are built with the spec-driven-execution skill: a Planner, Implementer, and Verifier sub-agent on top of tlc-spec-driven. Read that skill before starting any phase or feature.

Testing principles (high level)

These are the rules that govern every test in this repo. Details and tooling versions live with each project; this is the contract.

  1. Server authority is the test boundary. All game-outcome logic (damage, XP, drops, position, cooldowns, peace zone) is tested on the server. The client is never trusted and never the source of truth in a test.
  2. Tests derive from spec acceptance criteria. A test asserts a spec-defined outcome. It never mirrors the implementation, and we never weaken or skip a test to make it pass. The test runner decides "done".
  3. Three test layers — pick the cheapest one that proves the criterion:
  • Unit (server + client) — formulas, curves, rules, DOM/hook mapping. The bulk of our tests.
  • Room integration (@colyseus/testing) — join/leave, intent validation, state broadcast, persistence/reconnect. Proves "no client trust" without a browser.
  • Seed/data — the L2J XML → SQLite seed produced the expected Classic values (mobs, NPCs, skill, XP curve).
  1. WebGL is not directly testable in Vitest. Assert HUD/DOM in client unit tests, and assert logical game state through window.__GAME_STATE__ and wireRoom tests. Do not anchor correctness on pixel screenshots in the test gate.
  2. Determinism. Anything random (drop chance, damage variance) runs through an injected seeded RNG so tests and the Verifier's fault-injection are reliable.
  3. Independent verification. After implementation, a fresh Verifier (author ≠ verifier) re-checks against the spec and injects behavior-level faults to confirm the tests actually catch regressions.
  4. Run only what changed. Use nx affected and Nx caching so the gate is fast every time; never disable the cache to force a pass.
  5. Tests are the source of confidence — keep them HIGH QUALITY and FAST. The test suite is what lets agents (and humans) trust a change without re-reading everything. Treat tests as first-class code: clear, deterministic, isolated, and quick. Fast feedback is a hard requirement, not a nice-to-have — agents stall and burn cycles waiting on slow suites, which is a real failure mode here.

Read the full file on GitHub · 88 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. 10d ago First seen · 88 lines · 1,182 tokens per session scan A 4b9f9239eb49

Subscribe to this mod's changes

nj-mmo AGENTS.md is an instructions file published in the GitHub repository tech-leads-club/nj-mmo (23 stars, last pushed 2mo ago), licensed MIT. It adds 1,182 tokens to every session, about $0.0059 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 2026-08-30.

Related

Other instructions, from other repositories

next.js AGENTS.md

AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

openai/codex · 5,153 tokens

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

spec-kit AGENTS.md

AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.

github/spec-kit · 7,104 tokens

vscode oss-third-party-notices.instructions.md

Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).

microsoft/vscode · 5,001 tokens

langchain AGENTS.md

AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.

langchain-ai/langchain · 4,469 tokens