agentmods.dev

opal AGENTS.md

Project instructions for Opal, a coding-agent framework written in Elixir. They describe its architecture, command-line interface, built-in tools, and development commands.

In plain words
What is it for?
Use them when working on Opal's agent engine, terminal interface, file and shell tools, child agents, or task tracker, and when running its development checks.
Why use it?
They give an agent the project-specific context needed to modify Opal consistently. They also document the commands used to run, test, lint, and release the project.

Instructions file for CodexOpenCode

58 20d ago A scan 206 tokens original MIT
View the source file matteing/opal
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/matteing/opal/agents-md
Clone the repo
git clone --depth 1 https://github.com/matteing/opal

Made for: Codex, OpenCode.

Per session 206 This file is loaded in full into every session.
When invoked 206 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 $0.00206 $0.00206
Opus 5 $0.00103 $0.00103
Sonnet 5 $0.00041 $0.00041
Haiku 4.5 $0.00021 $0.00021

Measured 2d ago against content hash 893cb4e8609c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

opal 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 · 31 lines

What it actually says

Opal Project Guide

Opal is a coding agent harness built with Elixir/OTP for AI coding agents.

Architecture

  • Everything is a Process - Agent loops, sessions, and tools are GenServers
  • Cross-Platform - Works on macOS, Linux, and Windows

Components

  • opal/ - Elixir SDK (agent engine, tools, providers)
  • cli/ - Terminal UI application

Built-in Tools

  • read_file, write_file, edit_file - File operations with hashline tags
  • grep - Cross-platform search with glob filtering
  • shell - Cross-platform command execution
  • sub_agent - Spawn child agents for parallel work
  • tasks - Task tracker for planning

Development

mise run dev    # Run TUI
mise run test   # Run tests
mise run lint   # Check code quality
mise run release # Release
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 · 31 lines · 206 tokens per session scan A 893cb4e8609c

Subscribe to this mod's changes

opal AGENTS.md is an instructions file published in the GitHub repository matteing/opal (58 stars, last pushed 20d ago), licensed MIT. It adds 206 tokens to every session, about $0.0010 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.

Data and AILLMLanguagesPlanningagentsaiai-agentsclielixir
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