mythos-router: Instructions file for Codex

AGENTS.md

mythos-router AGENTS.md is an instructions file for Codex, OpenCode from thewaltero/mythos-router. It costs 2,232 tokens per session, scanned A, original, MIT.

A project instruction file describing the identity, architecture, conventions, and file-handling rules of the mythos-router TypeScript command-line project. An AGENTS.md file gives coding agents repository-specific guidance.

In plain words
What is it for?
Use it when working on mythos-router so the agent understands its Node.js setup, source layout, policies, run records, and change protocol.
Why use it?
It gives an agent the project context and operating rules needed to make changes that fit the existing codebase.

Instructions file for CodexOpenCode

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

This is thewaltero/mythos-router's own configuration. It tells Codex and OpenCode how to work on mythos-router 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 mythos-router configures →

Reuse

Borrowing it

Nothing to install: this file belongs to thewaltero/mythos-router. 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/thewaltero/mythos-router/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/thewaltero/mythos-router

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 mythos-router AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/thewaltero/mythos-router/agents-md.svg)](https://agentmods.dev/instructions/thewaltero/mythos-router/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/thewaltero/mythos-router/agents-md"><img src="https://agentmods.dev/badge/instructions/thewaltero/mythos-router/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 2,232 This file is loaded in full into every session.
When invoked 2,232 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 $0.02232 $0.02232
Opus 5 $0.01116 $0.01116
Sonnet 5 $0.00446 $0.00446
Haiku 4.5 $0.00223 $0.00223

Measured 8d ago against content hash e373a36091bd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

mythos-router 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 · 128 lines

How it starts

The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md - mythos-router Project Standards

Project Identity

  • Name: mythos-router
  • Type: CLI power tool (local-first, zero-slop)
  • Stack: TypeScript on Node.js 20+ (ESM, tsx for dev)

Architecture

  • src/mcp-config.ts - Paste-ready MCP client configuration helper
  • src/project-policy.ts - Repo-local .mythos/policy.json loader and matcher
  • src/policy-suggestions.ts - Read-only repo inspection for suggested SWD guardrails
  • src/action-schema.ts - External-agent action schema, task contract validation, and input validation
  • src/runs.ts - Local external-agent run outcome ledger (.mythos/runs)
  • src/cli.ts - Commander.js entry point
  • src/config.ts - Constants, system prompt, validation, budget defaults
  • src/client.ts - Provider facade and Anthropic direct-client compatibility path
  • src/budget.ts - Session budget limiter (token cap, turn cap, progress bar)
  • src/swd.ts - SWD execution kernel (engine, types, parsing, snapshots, verification, rollback)
  • src/swd-cli.ts - SWD terminal presentation layer (verification output, dry-run preview)
  • src/sandbox.ts - Isolated temp repo copy gate for external-agent checks before real writes
  • src/receipts.ts - SWD trust receipts (creation, storage, drift verification)
  • src/memory.ts - Self-healing MEMORY.md manager (SQLite FTS5 derivative index)
  • src/metrics.ts - Global metrics store (persistent budget tracking)
  • src/diff.ts - Myers' diff algorithm (zero-dependency, line-by-line)
  • src/git.ts - Git operations (branching, committing, status)
  • src/mcp.ts - MCP stdio adapter for SWD, receipts, and skills tools
  • src/utils.ts - Terminal colors, spinner, formatting, badges, confirm prompt
  • src/index.ts - Public SDK exports (SWDEngine, parseActions, etc.)
  • src/commands/chat.ts - Interactive REPL and one-shot run orchestration (ChatSession + ChatUI abstraction)
  • src/commands/swd.ts - Model-free external-agent SWD apply/validate command
  • src/commands/mcp.ts - MCP stdio server command (mythos mcp)
  • src/commands/runs.ts - Local external-agent run list/show command
  • src/commands/policy.ts - Project policy suggestion command
  • src/commands/init.ts - Project initialization (environment checks, provider detection, scaffolding)
  • src/commands/verify.ts - Codebase to Memory drift scanner (dry-run aware)
  • src/commands/receipts.ts - SWD receipt list/show/verify command
  • src/commands/dream.ts - Memory compression (dry-run aware)
  • src/commands/stats.ts - Budget analytics reporter

Read the full file on GitHub · 128 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 · 128 lines · 2,232 tokens per session scan A e373a36091bd

Subscribe to this mod's changes

mythos-router AGENTS.md is an instructions file published in the GitHub repository thewaltero/mythos-router (298 stars, last pushed 3d ago), licensed MIT. It adds 2,232 tokens to every session, about $0.0112 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.

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