regenerator2000: Skill for Claude Code

.agent/skills/compare-unpacker/SKILL.md

compare-unpacker is a skill for Claude Code, Codex from ricardoquesada/regenerator2000. It costs 43 tokens per session (1,191 once invoked), scanned A, original, Apache-2.0.

A comparison tool for checking a Commodore 64 program unpacker against unp64, another unpacking program. It compares the detected start address, end address, and entry point for registered PRG binary test files.

In plain words
What is it for?
Use it to run comparisons, find matching and differing address results, and create a Markdown report of the findings.
Why use it?
It makes differences between the two unpackers visible across the project's test files instead of checking each result manually.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is ricardoquesada/regenerator2000's own configuration. It tells Claude Code and Codex how to work on regenerator2000 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 regenerator2000 configures →

Reuse

Borrowing it

Nothing to install: this file belongs to ricardoquesada/regenerator2000. 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/ricardoquesada/regenerator2000/main/.agent/skills/compare-unpacker/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/ricardoquesada/regenerator2000

Made for: Claude Code, Codex.

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 compare-unpacker

README.md
[![agentmods](https://agentmods.dev/badge/skills/ricardoquesada/regenerator2000/compare-unpacker/github.svg)](https://agentmods.dev/skills/ricardoquesada/regenerator2000/compare-unpacker)
Your own site
<a href="https://agentmods.dev/skills/ricardoquesada/regenerator2000/compare-unpacker"><img src="https://agentmods.dev/badge/skills/ricardoquesada/regenerator2000/compare-unpacker/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for compare-unpacker

Your own site · 80×15
<a href="https://agentmods.dev/skills/ricardoquesada/regenerator2000/compare-unpacker"><img src="https://agentmods.dev/badge/skills/ricardoquesada/regenerator2000/compare-unpacker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,191 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 22
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
How audits are shown
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 $0.00043 $0.01191
Opus 5 $0.00022 $0.00596
Sonnet 5 $0.00009 $0.00238
Haiku 4.5 $0.00004 $0.00119

Measured 10d ago against content hash 33775b0684ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

compare-unpacker 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 10d 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.

.agent/skills/compare-unpacker/SKILL.md · 100 lines

How it starts

The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Unpacker Comparison Skill (compare-unpacker)

Use this skill when you need to benchmark or compare the Regenerator 2000 unpacker against unp64 across all test PRG binaries registered in test_unpack_known_prg_files.

Single Source of Truth

The single source of truth for test PRG files is test_unpack_known_prg_files in crates/regenerator2000-core/src/unpacker.rs.

The comparison tool (crates/regenerator2000-core/src/bin/unpacker_compare_all.rs) dynamically parses unpacker.rs to extract the exact list of active test PRGs. Do not hardcode the total count of test files in reports or documentation.


Workflow Overview

  1. Execute Comparison Binary: Run unpacker_compare_all to execute both unp64 and Regenerator 2000's unpack() engine on all test files dynamically extracted from test_unpack_known_prg_files.
  2. Analyze Output: Extract and compare start address, end address, and entry point for every binary.
  3. Generate Report Artifact: Create a comprehensive Markdown comparison report summarizing results, exact matches, and categorized discrepancies.

Step 1: Run the Comparison Tool

Execute the comparison binary:

cargo run -p regenerator2000-core --bin unpacker_compare_all

Note: The binary automatically looks for unp64 in PATH, ~/.local/bin/unp64, ~/bin/unp64, or via the UNP64 / UNP64_PATH environment variable. If unp64 is in a custom location, specify UNP64=/path/to/unp64 cargo run ....


Step 2: Analyze & Categorize Discrepancies

For each file listed by the tool, examine the three primary fields:

  • Start Address (start_addr): Range start address (unp64 vs R2000).
  • End Address (end_addr): Range end address (unp64 vs R2000).
  • Entry Point (entry_point): Program entry point address (unp64 vs R2000).

Read the full file on GitHub · 100 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. 10d ago First seen · 100 lines · 43 tokens per session scan A 33775b0684ec

Subscribe to this mod's changes

compare-unpacker is a skill published in the GitHub repository ricardoquesada/regenerator2000 (164 stars, last pushed 15d ago), licensed Apache-2.0. It adds 43 tokens to every session and 1,191 once invoked, about $0.0002 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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