yaks AGENTS.md

yaks AGENTS.md is an instructions file for Codex, OpenCode from mattwynne/yaks. It costs 1,106 tokens per session, scanned C, original, MIT.

A set of development rules for Yaks, a task-tracking tool built with an architecture where commands create stored events and read views. It covers the system structure, testing layers, and development workflow.

In plain words
What is it for?
Use it when changing Yaks commands, events, read models, policies, or command-line behavior. It guides acceptance tests, shell tests, integration tests, and mutation testing.
Why use it?
It helps contributors place changes in the right part of the system and choose the appropriate kind of test. It also explains when architectural decisions need special review.

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

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 yaks AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/mattwynne/yaks/agents-md.svg)](https://agentmods.dev/instructions/mattwynne/yaks/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/mattwynne/yaks/agents-md"><img src="https://agentmods.dev/badge/instructions/mattwynne/yaks/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,106 This file is loaded in full into every session.
When invoked 1,106 The same file — it is already loaded in full.
Security scan C 1 finding. 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 5.1 $0.01106 $0.01106
Opus 5 $0.00553 $0.00553
Sonnet 5 $0.00221 $0.00221
Haiku 4.5 $0.00111 $0.00111

Measured 5d ago against content hash 10e05ff2117a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade C, and why

yaks AGENTS.md scanned grade C with 1 finding 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 5d 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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

- **NEVER**: Run `rm -rf .yaks` or modify `.yaks` contents directly
AGENTS.md · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.

This file provides guidance to Agents working in this repository.

We use yaks for task tasking. See !yx help

See CONTRIBUTING for dev tooling and commands.

Architecture

Hexagonal architecture with CQRS and Event Sourcing. Commands flow through use cases to the YakMap aggregate, which emits domain events. Events are persisted to git refs and projected to the .yaks/ directory-based read model.

See src/README.md for the full architecture guide: layers, key types, ports, adapters, and how commands flow.

See docs/adr/ for Architecture Decision Records explaining why the design is the way it is.

When making architectural decisions, invoke the cqrs-event-sourcing skill for guidance on aggregate boundaries, event design, read models, policies, and sagas.

Testing layers

  • Cucumber acceptance tests (features/*.feature): For executable specifications, agreed with human partner. Dual-mode execution via cargo test --test cucumber --features test-support:
    • FullStackWorld: spawns yx binary (real integration test)
    • InProcessWorld: calls Rust directly with in-memory adapters (fast)
  • ShellSpec tests (tests/shellspec/): For tests that don't fit Cucumber (tmux smoke, git checks, installer). Run with shellspec.
  • Rust unit tests: Internal logic (cargo test)

Mutation Testing

Validates test quality by injecting code changes and checking tests catch them.

dev mutate-diff         # Fast: only mutants in your changes (~seconds)
dev mutate              # Full run (~7 min, ~400 mutants)
dev mutate -F 'slug'    # Full run filtered to specific files
dev mutate-sync         # Sync missed mutants to yaks

Daily workflow: Use dev mutate-diff (alias dev md) while coding.

After a full run: dev mutate-sync (alias dev ms) creates yaks for missed mutants. Then yx sync to share results.

Config: .cargo/mutants.toml excludes infrastructure-only files.

Read the full file on GitHub · 126 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. 5d ago First seen · 126 lines · 1,106 tokens per session scan C 10e05ff2117a

Subscribe to this mod's changes

yaks AGENTS.md is an instructions file published in the GitHub repository mattwynne/yaks (58 stars, last pushed 24d ago), licensed MIT. It adds 1,106 tokens to every session, about $0.0055 per session on Opus 5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.