mythos AGENTS.md

Project instructions for Mythos Atlas, a mythology encyclopedia built as a pnpm and Turborepo monorepo. A monorepo keeps multiple related applications in one repository; these instructions explain its apps, setup, design rules, and development commands.

In plain words
What is it for?
Use them when working on the web or optional API app, setting up the project, running development commands, configuring local environment values, or creating interface changes that must follow the project design system.
Why use it?
They give coding agents the project context and rules needed to make changes in the correct application and follow the established design and development setup.

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/forbiddenlink/mythos/agents-md
Clone the repo
git clone --depth 1 https://github.com/forbiddenlink/mythos

Made for: Codex, OpenCode.

Per session 1,710 This file is loaded in full into every session.
When invoked 1,710 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 $0.01710 $0.01710
Opus 5 $0.00855 $0.00855
Sonnet 5 $0.00342 $0.00342
Haiku 4.5 $0.00171 $0.00171

Measured 2d ago against content hash af666d96958d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mythos 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 2d 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 · 161 lines

How it starts

The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file provides guidance to WARP (warp.dev) when working with code in this repository.

Design system: before generating any UI, read apps/web/public/design-system.txt (machine-readable token + component contract). Token SoT = apps/web/src/app/globals.css; philosophy = .impeccable.md.

Project Overview

Mythos Atlas is an interactive mythology encyclopedia. It's a pnpm + Turborepo monorepo with two apps:

  • apps/web — Next.js 16 (App Router) + React 19 frontend. Serves a GraphQL API from a Next.js route handler backed by static JSON data files. This is the primary app where most development happens.
  • apps/api — Rust (Axum + async-graphql + SQLx) backend targeting PostgreSQL. This is a secondary/optional backend that mirrors the GraphQL API.

In practice, the web app is self-contained: its /api/graphql route handler reads directly from JSON files in src/data/, so the Rust API is not required for local development.

Commands

All commands are run from the monorepo root unless noted otherwise.

Setup

pnpm install
cp apps/web/.env.example apps/web/.env.local  # then add ANTHROPIC_API_KEY / Upstash for Oracle

Development

pnpm dev                     # starts all apps via Turborepo (web on :3000)
pnpm --filter web dev        # start only the web app

Build

pnpm build                   # build all apps
pnpm --filter web build      # build only web (uses --webpack flag for next-pwa compatibility)

Lint & Typecheck

pnpm lint                              # ESLint across all apps
pnpm --filter web exec tsc --noEmit    # TypeScript type check (web)

Testing — Unit (Vitest)

Run from root or scoped to web:

pnpm --filter web test              # run all unit tests once
pnpm --filter web test:watch        # watch mode
pnpm --filter web test:coverage     # with coverage (thresholds: 80% lines/functions/statements, 70% branches)

Run a single test file:

pnpm --filter web exec vitest run src/__tests__/lib/search.test.ts

Read the full file on GitHub · 161 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. 2d ago First seen · 161 lines · 1,710 tokens per session scan A af666d96958d

Subscribe to this mod's changes

mythos AGENTS.md is an instructions file published in the GitHub repository forbiddenlink/mythos (2 stars, last pushed 3d ago), licensed MIT. It adds 1,710 tokens to every session, about $0.0086 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.