fonline AGENTS.md

A maintainer guide for the reusable FOnline game engine, the shared software used by games such as Last Frontier.

In plain words
What is it for?
Use it before changing engine code, build tools, resources, tests, or documentation, and when checking whether a feature is reusable across games.
Why use it?
It helps determine whether a change belongs in the engine or in the game that embeds it, while keeping source code and documentation consistent.

Instructions file for CodexOpenCode

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 instructions/cvet/fonline/agents-md
Clone the repo
git clone --depth 1 https://github.com/cvet/fonline

Made for: Codex, OpenCode.

Per session 5,862 This file is loaded in full into every session.
When invoked 5,862 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.05862 $0.05862
Opus 5 $0.02931 $0.02931
Sonnet 5 $0.01172 $0.01172
Haiku 4.5 $0.00586 $0.00586

Measured 3d ago against content hash 4412211280b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fonline 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 3d 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 · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FOnline Engine — AI Maintainer Guide

This is the AI entry point for the reusable FOnline engine repository. For the human entry point, start with README.md. For the documentation map, start with Docs/README.md.

Scope

  • This repository is the reusable engine submodule used by games such as Last Frontier.
  • Engine-owned code lives under Source/, BuildTools/, Resources/, and engine tests under Source/Tests/.
  • Game-specific content, scripts, native extensions, CI glue, and launch presets live in the embedding project and should not be moved into the engine unless the behavior is genuinely reusable.

Before Changing Anything

  1. Check whether the change belongs to the engine or to the embedding game project.
  2. Read the nearest existing code and follow its style; do not introduce parallel conventions.
  3. Verify before editing: docs may drift, and when a doc and the live source disagree, the source wins — fix the doc in the same change.
  4. If behavior changes, update the owning engine doc in Docs/ in the same worktree change.
  5. Do not commit or push unless explicitly asked by the repository owner.
  6. Treat published branch history as immutable. Once the branch has a remote tip, do not rebase, reset, amend, or force-push it; merge upstream and the published tip so every publication is a fast-forward. Verify with git merge-base --is-ancestor <remote-tip> HEAD before pushing, and stop instead of rewriting history when that check fails.

Documentation Map

The full maintained index is Docs/README.md; use it when a topic is not listed here. Convention-critical docs for maintainers:

Read the full file on GitHub · 108 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. 3d ago First seen · 108 lines · 5,862 tokens per session scan A 4412211280b8

Subscribe to this mod's changes

fonline AGENTS.md is an instructions file published in the GitHub repository cvet/fonline (334 stars, last pushed 3d ago), licensed MIT. It adds 5,862 tokens to every session, about $0.0293 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.