PET-Project AGENTS.md

PET-Project AGENTS.md is an instructions file for Codex, OpenCode from nschneir/PET-Project. It costs 1,766 tokens per session, scanned A, original, MIT.

Repository instructions for PET Project, a toolkit for developing and debugging Commodore PET programs on the VICE emulator. It includes a command-line interface and an MCP server that use the same session system.

In plain words
What is it for?
It helps install the project, run its test suite, use the CLI and MCP interfaces, and work on Commodore PET or 6502 assembly software.
Why use it?
It tells coding agents where project information lives and which tests and commands to run. This reduces confusion when working across the CLI, MCP server, emulator, and documentation.

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/nschneir/pet-project/agents-md
Clone the repo
git clone --depth 1 https://github.com/nschneir/PET-Project

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 PET-Project AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/nschneir/pet-project/agents-md.svg)](https://agentmods.dev/instructions/nschneir/pet-project/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/nschneir/pet-project/agents-md"><img src="https://agentmods.dev/badge/instructions/nschneir/pet-project/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,766 This file is loaded in full into every session.
When invoked 1,766 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 $0.01766 $0.01766
Opus 5 $0.00883 $0.00883
Sonnet 5 $0.00353 $0.00353
Haiku 4.5 $0.00177 $0.00177

Measured 4d ago against content hash 91153708b289, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

PET-Project 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 4d 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 · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Instructions for AI coding agents working on this repository's code. (If you are here to use pet-tools to write PET software, read skills/pet-development/SKILL.md and docs/cli.md instead.)

What this is

PET Project (package petlib, distributed as pet-tools): an AI-oriented toolset for developing and debugging Commodore PET software on the VICE emulator. Two front ends — the pet CLI and the pet-tools-mcp MCP server — drive the same session machinery.

Where things are documented (don't duplicate them here):

  • README.md — install, quickstart, supported PET models.
  • docs/agent-setup.md — per-agent setup (CLI and MCP routes), macOS + Linux.
  • docs/cli.md — the full CLI reference (man page), one entry per command.
  • skills/pet-development/ + skills/6502-assembly/ — PET/6502 domain knowledge: workflows, memory maps, zero page, ROM routines, cookbook.

Commands

pip install -e ".[dev]"        # install with pytest + coverage

pytest                          # full suite (vice-marked tests need xpet/VICE on PATH)
pytest -m "not vice"            # unit tests only — no emulator required
pytest tests/test_monitor.py    # one file
pytest tests/test_monitor.py::test_name   # one test

python -m coverage run -m pytest && python -m coverage combine && python -m coverage report
                                # coverage (fail_under=90); subprocesses (daemon, MCP stdio) are measured too

ruff check src tests            # lint (config in pyproject.toml); must be clean

Tests marked @pytest.mark.vice launch a real VICE emulator (xpet); everything else runs against tests/fake_vice.py, an in-process fake of the VICE binary monitor. pet build needs cc65 (ca65/ld65); pet basic needs petcat; pet disk needs c1541 — all external subprocesses.

Live-test caution: a setup failure inside a vice-marked test can skip teardown and leak a warp-mode xpet eating a CPU core. Check pgrep -fl xpet between live runs and kill leftovers. Give live tests generous timeouts (minutes, not seconds).

Read the full file on GitHub · 112 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. 4d ago First seen · 112 lines · 1,766 tokens per session scan A 91153708b289

Subscribe to this mod's changes

PET-Project AGENTS.md is an instructions file published in the GitHub repository nschneir/PET-Project (1 stars, last pushed 11d ago), licensed MIT. It adds 1,766 tokens to every session, about $0.0088 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.