Audio Plugin Coder (APC)

AI-powered open-source framework for vibe-coding audio plugins from concept to shipped product

What's new

JUCE 9 — framework pin upgraded to 9.0.1, including the official @juce-framework/webview / TypeScript WebView interop path
/apc-setup — guided first-run wizard for toolchain checks, relocatable plugins / build / release folders, UI defaults, and per-phase AI model preferences
Optional Codex cost routing — /apc-setup can enable Luna→Terra→Sol→Astra CLI orchestration (docs/codex-orchestration.md)
/apc-* commands — unique slash names (/apc-dream, /apc-plan, …) for Claude Code/Kilo/Cursor; Codex invokes APC through its skill syntax
Cross-platform — Windows, macOS, and Linux (Linux needs WebKitGTK + EGL for JUCE 9)

Start here: clone → /apc-setup (Claude Code/Kilo/Cursor) or $audio-plugin-coder:audio-plugin-coder setup (Codex) → start the workflow.

About Audio Plugin Coder

Audio Plugin Coder (APC) is the result of a long-standing personal obsession: building creative tools, writing music, and ultimately creating professional audio plugins.

While developing software instruments and effects has always been a dream, building real-world VSTs (with robust DSP, UI, state handling, and packaging) is notoriously complex. Over time, and especially with the rapid advancement of AI-assisted development, that barrier has finally crumbled.

Over the past 18 months, APC has been continuously designed, tested, and re-iterated as a practical AI-first framework for building audio plugins. This involved thousands of hours of experimentation, trial-and-error, and yes... occasionally yelling at LLMs to finally render the UI correctly.

APC is designed to be Agent Agnostic. Whether you use Codex, Google's Antigravity, Kilo, Claude Code, or Cursor, APC provides the structure they need to succeed.

APC is under active improvement — expect iteration — but the core workflow (setup → dream → plan → design → impl → ship) is ready for real plugin development on Windows, macOS, and Linux.

What is Audio Plugin Coder?

Audio Plugin Coder (APC) is a structured, AI-driven workflow system that guides LLM agents through the entire audio plugin development lifecycle.

It enables the creation of VST3 / AU / CLAP plugins using natural language, predefined workflows, and domain-specific skills- without constantly re-explaining context, architecture, or best practices to the AI.

Instead of manually juggling DSP architecture, UI frameworks, build systems, state tracking, and packaging, APC provides a unified framework where AI agents can operate with long-term context, validation, and self-improving knowledge.

✨ Key Features

🤖 LLM-Driven Development - Designed to work with Codex, Antigravity, Kilo, Claude Code, Cursor, or any coding agent.
🧭 Guided Setup - /apc-setup configures toolchain, paths, and model routing via apc.config.json.
🎯 Structured Workflows - Dream → Plan → Design → Implement → Ship (plus test/debug/status/resume).
🏷️ Unique slash commands - /apc-* primary names; short aliases kept for compatibility.
🎨 Dual UI Frameworks - Choose Visage (pure C++) or WebView (HTML/CSS/JS + JUCE WebView).
📊 State Management - Automatic progress tracking, validation, and rollback capabilities.
🔧 Self-Improving - Auto-capture troubleshooting knowledge; the system gets smarter over time.
🏗️ JUCE 9 + CMake - Modern plugin stack with relocatable plugins/build/release directories.
📚 Comprehensive Skills - Pre-built domain knowledge for DSP, UI design, testing, and packaging.
🎬 Bridge Templates - FFGL visual plugins and Max/MSP externals support.

🚀 Quick Start

One-command setup

The fastest way to get started — paste this into any terminal:

npx github:Noizefield/audio-plugin-coder

This will clone the repo, check your tools, and print exactly what to do next for your platform (Windows, macOS, or Linux). Requires Node.js 18+ and Git.

Always pulls the latest version directly from GitHub — no install, no package manager.

Manual setup

If you prefer to clone manually:

Windows:

git clone --recurse-submodules https://github.com/Noizefield/audio-plugin-coder.git
cd audio-plugin-coder
.\scripts\system-check.ps1 -Human

macOS / Linux:

git clone --recurse-submodules https://github.com/Noizefield/audio-plugin-coder.git
cd audio-plugin-coder
bash scripts/system-check.sh --human

Then open the repo in your AI agent and run:

/apc-setup — configure paths, models, verify JUCE 9
/apc-dream <PluginName> — create your first plugin

Codex command syntax

Codex does not expose repo-defined, unnamespaced slash commands such as /apc-dream. Use the APC skill action instead:

$audio-plugin-coder:audio-plugin-coder setup
$audio-plugin-coder:audio-plugin-coder dream MyPlugin

The bare /apc-* commands are the Claude Code/Kilo form. Do not use Codex built-ins such as /plan or /status for APC phases.

Prerequisites

Windows

An LLM coding agent (Claude Code, Antigravity, Kilo, Codex, Cursor)
Git · Node.js (≥18) · Python (≥3.8) · Visual Studio 2022 C++ · CMake (≥3.22) · WebView2 Runtime · JUCE (≥9, via submodule) · pluginval (submodule)

macOS

An LLM coding agent (Claude Code, Antigravity, Kilo, Codex, Cursor)
macOS 10.13+ · Xcode + Command Line Tools · CMake (≥3.22) · Git (submodules) · Node.js (≥18) · Python (≥3.8) · jq · JUCE (≥9, via submodule) · pluginval (submodule)
WebView uses system WKWebView (no separate WebView2 install)

Linux

An LLM coding agent (Claude Code, Antigravity, Kilo, Codex, Cursor)
GCC 9+ or Clang 10+ with C++20 · CMake (≥3.22) · Git (submodules) · make or ninja · Node.js (≥18) · Python (≥3.8) · jq recommended
WebKitGTK (WebView) · libegl-dev / EGL (JUCE 9 OpenGL) · JUCE (≥9, via submodule) · pluginval (submodule)
ALSA (and optionally JACK) for Standalone audio

Bridge Templates (FFGL & Max/MSP)

If you are specifically interested in building FFGL Visual Plugins or Max for Live Externals, use the included One-Click Setup script for Windows:

.\scripts\setup_bridges.bat

This script will:

Check for CMake and Git.
Automatically download JUCE 9 (if missing).
Configure the Visual Studio solution for your chosen bridge.
Open the project ready for compilation.

Initialize your LLM agent

For Kilo / Claude Code: workflows are discovered from .claude/workflows/ (mirrored under .agent/ / .kilocode/).

For Codex:

# AGENTS.md and the repo-local skill are discovered automatically
$audio-plugin-coder:audio-plugin-coder setup
$audio-plugin-coder:audio-plugin-coder dream MyReverb

For Claude Code / Kilo / Cursor:

/apc-setup
/apc-dream MyReverb

The AI will guide you through the entire process!

📖 How It Works

The Five-Phase Workflow

🧭 SETUP (first run)
↓ Toolchain, paths, model preferences
💭 DREAM (Ideation)
↓ Create creative brief, define parameters
📋 PLAN (Architecture)
↓ Design DSP graph, select UI framework
🎨 DESIGN (GUI)
↓ Create mockups, iterate on visual design
💻 IMPLEMENT (Code)
↓ Build DSP engine, integrate UI
🚀 SHIP (Package)
↓ Build installers, test in DAWs

Agent Commands

Prefer the /apc-* names (unique across frameworks). Short forms (/dream, /plan, …) still work as deprecated aliases.

Codex uses the audio-plugin-coder skill because /plan and /status are built-in Codex commands.

Primary (Claude Code / Kilo / Cursor)	Codex	Description
`/apc-setup`	`$audio-plugin-coder:audio-plugin-coder setup`	First-run toolchain, paths, models
`/apc-dream [Name]`	`$audio-plugin-coder:audio-plugin-coder dream [Name]`	Start new plugin (ideation)
`/apc-plan [Name]`	`$audio-plugin-coder:audio-plugin-coder plan [Name]`	Architecture + UI framework
`/apc-design [Name]`	`$audio-plugin-coder:audio-plugin-coder design [Name]`	GUI mockups and visual design
`/apc-impl [Name]`	`$audio-plugin-coder:audio-plugin-coder impl [Name]`	Implement DSP and UI
`/apc-test [Name]`	`$audio-plugin-coder:audio-plugin-coder test [Name]`	Run tests / validation
`/apc-debug [Name]`	`$audio-plugin-coder:audio-plugin-coder debug [Name]`	Diagnose and fix issues
`/apc-ship [Name]`	`$audio-plugin-coder:audio-plugin-coder ship [Name]`	Package and distribute
`/apc-status [Name]`	`$audio-plugin-coder:audio-plugin-coder status [Name]`	Progress and state
`/apc-resume [Name]`	`$audio-plugin-coder:audio-plugin-coder resume [Name]`	Continue from last incomplete phase
`/apc-new [Name]`	`$audio-plugin-coder:audio-plugin-coder new [Name]`	Full workflow with confirmations

See Command Reference, Codex Compatibility, and Model Routing.

Example Session

You: /apc-setup
AI: Let's configure APC (paths, models, JUCE check)...
✅ Setup complete. Next: /apc-dream <PluginName>
You: /apc-dream TapeDelay
AI: Great! Let's define your plugin concept.
What is the sonic character?
(e.g., "Warm analog tape delay with wow/flutter")
You: Vintage tape echo with analog saturation
AI: Perfect! What are the top 3-5 parameters you want?
You: Delay time, feedback, wow/flutter amount, saturation, mix
AI: ✅ Dream phase complete!
Files created:
- plugins/TapeDelay/.ideas/creative-brief.md
- plugins/TapeDelay/.ideas/parameter-spec.md
- plugins/TapeDelay/status.json
Next step: /apc-plan TapeDelay

🏗️ Architecture & Self-Correction

APC uses a unique State Management system (status.json) to track development across phases. This allows you to pause, switch agents, or restart specific phases without losing context.

Directory Structure

audio-plugin-coder/
├── AGENTS.md # Agent guidance (AGENTS.md standard)
├── .agents/skills/ # Codex repo-local skill discovery
├── .codex-plugin/plugin.json # Codex plugin manifest
├── skills/ # Packaged Codex skill
├── .[Agent]/ # AI agent configuration
│ ├── workflows/ # Slash command orchestrators
│ │ ├── dream.md
│ │ ├── plan.md
│ │ ├── design.md
│ │ ├── impl.md
│ │ └── ship.md
│ ├── skills/ # Domain knowledge modules
│ │ ├── skill_ideation/
│ │ ├── skill_planning/
│ │ ├── skill_design/
│ │ ├── skill_implementation/
│ │ └── skill_packaging/
│ ├── guides/ # Reference documentation
│ │ └── state-management-guide.md
│ ├── rules/ # System constraints
│ │ ├── agent.md
│ │ └── file-naming-conventions.md
│ └── troubleshooting/ # Auto-captured issues
│ ├── known-issues.yaml
│ └── resolutions/
├── templates/ # Plugin templates (consolidated)
│ ├── visage/ # Visage (C++) UI templates
│ ├── webview/ # WebView (HTML5) UI templates
│ ├── ffgl/ # FFGL visual plugin templates
│ ├── max-external/ # Max/MSP external templates
│ └── status-template.json # Plugin state template
├── docs/ # Comprehensive documentation
├── plugins/ # Generated plugins
│ └── [YourPlugin]/
│ ├── .ideas/ # Specs and planning
│ ├── Design/ # UI mockups
│ ├── Source/ # C++ code
│ └── status.json # State tracking
├── scripts/ # Build automation
│ ├── build-and-install.ps1 # Windows build script
│ ├── build-and-install.sh # macOS build script
│ ├── state-management.ps1 # Windows state management
│ ├── state-management.sh # macOS state management
│ └── installer/ # Platform-specific installers
├── build/ # Compilation artifacts
└── release/ # Ship packages (installers, zips)

How Skills Work

Skills contain domain knowledge (the "how"):

Step-by-step instructions
Best practices
Framework-specific guidance
Code generation patterns

Workflows orchestrate skills (the "when"):

Prerequisites validation
Phase transitions
State management
Error recovery

Example: The /design workflow checks your UI framework selection (Visage or WebView) from status.json, then loads the appropriate design skill automatically.

🎨 UI Framework Options

Visage (Pure C++) - Experimental

Native C++ UI via Visage frames
High performance, low overhead
Full C++ control
Custom rendering with visage::Frame

Note: Visage integration is in active testing and may be unstable on some hosts.

WebView (HTML5 Canvas)

Modern web technologies
Rapid iteration with hot reload
Rich component libraries
Canvas-based rendering for performance

The AI helps you choose based on your plugin's complexity and requirements during the planning phase.

🔧 State Management

Every plugin has a status.json file tracking:

Current development phase
UI framework selection
Completed milestones
Validation checkpoints
Error recovery points

Benefits:

Resume development any time
Validate prerequisites automatically
Rollback on errors
Track project history

🧠 Self-Improving Troubleshooting

APC includes an auto-capture system that learns from problems:

AI encounters error → Searches known issues database
If known → Applies documented solution immediately
If unknown → Attempts resolution, tracks attempts
After 3 attempts → Auto-creates issue entry
When solved → Documents solution for future use

Location:.agent/troubleshooting/

Result: The system gets smarter with every issue encountered!

🤝 Compatible AI Agents

APC works with any LLM-based coding agent that supports:

Custom workflows, skills, or reusable instructions
File system access
Shell execution (PowerShell on Windows, Bash on macOS/Linux)

Supported:

✅ Codex CLI / IDE (repo skill and AGENTS.md)
✅ Claude Code (Anthropic)
✅ Kilo (kilo.ai)
✅ Cursor
Others welcome!

🛠️ Technology Stack

JUCE 9 - Audio plugin framework (includes DSP, GUI, etc.)
CMake - Build system (Visual Studio on Windows, Xcode on macOS)
PowerShell / Bash - Automation scripting (platform-specific)
WebView2 / WKWebView - Web UI (Windows / macOS)
YAML - Knowledge base format
Markdown - Documentation and workflows

📋 Supported Plugin Formats

Format	Windows	macOS	Linux
VST3	✅	✅	✅
Standalone	✅	✅	✅
AU	❌	✅	❌
LV2	❌	❌	✅

CLAP support planned for future release.

📚 Documentation

Comprehensive documentation is available in the docs/ directory:

Getting Started - Documentation index and quick start
Plugin Development Lifecycle - Detailed phase guide
Command Reference - All commands and scripts
FAQ - Frequently asked questions
Troubleshooting - Common issues and solutions

🔮 Roadmap

💖 Sponsor the Project

I am an independent developer pouring hundreds of hours (and significant API costs) into this project.

Developing a framework that works across different AI agents means constantly testing against paid tiers of Claude, Gemini, and others. I often run out of "Plan" usage just testing a single workflow improvement.

If APC saves you time, helps you learn JUCE, or helps you ship a plugin, please consider supporting the development. It helps cover API costs and accelerates new features!

☕ Buy Me a Coffee / Sponsor on GitHub
Crypto/Other options TBD

🤝 Contributing & Community

Contributions are welcome! Join our GitHub Discussions to connect with the community.

Add Skills: Create new domain knowledge modules
Test Platforms: Verify compatibility with different AI agents
Improve Docs: Help us improve documentation
Share Plugins: Showcase what you've built

See CONTRIBUTING.md for details.

🙏 Acknowledgments

JUCE Team - For the industry-standard framework.
The AI Community - Specifically the meta-prompting pioneers.
Matt Tytel - For the outstandingly good Visage library (https://github.com/VitalAudio/visage)
12Matt3r - FFGL and Max/MSP bridge templates contribution.
vjcharles - macOS support and security hardening (PR #6).

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

⚠️ Important: JUCE Licensing Notice

APC uses JUCE 9 as its audio plugin framework. JUCE is dual-licensed:

License	Use Case	Requirements
AGPLv3	Open-source projects	Your plugin must be open-sourced under AGPLv3
JUCE Commercial	Closed-source/commercial	Requires purchasing a JUCE license

Key Points:

APC itself is MIT-licensed (permissive)
Plugins built with APC inherit JUCE's licensing requirements
If you sell your plugin or keep it closed-source, you need a JUCE commercial license
If you open-source your plugin under AGPLv3, you can use JUCE for free

Official JUCE Resources:

You are responsible for ensuring your use of JUCE complies with their licensing terms.

Built with ❤️ (and a lot of tokens) for the audio development community.

Turn your plugin ideas into reality with the power of AI

Name		Name	Last commit message	Last commit date
.agent		.agent
.agents/skills/audio-plugin-coder		.agents/skills/audio-plugin-coder
.claude		.claude
.codex-plugin		.codex-plugin
.codex/agents		.codex/agents
.cursor/rules		.cursor/rules
.githooks		.githooks
.github		.github
.kilocode		.kilocode
.opencode/command		.opencode/command
_tools		_tools
assets		assets
bin		bin
common		common
design_library		design_library
docs		docs
plugins		plugins
release		release
scripts		scripts
skills/audio-plugin-coder		skills/audio-plugin-coder
templates		templates
.codexignore		.codexignore
.gitignore		.gitignore
.gitmodules		.gitmodules
.plugin-scanner.toml		.plugin-scanner.toml
AGENTS.md		AGENTS.md
CHANGELOG.md		CHANGELOG.md
CMakeLists.txt		CMakeLists.txt
CONTRIBUTING.md		CONTRIBUTING.md
LICENCE.md		LICENCE.md
LICENSE		LICENSE
README.md		README.md
SECURITY.md		SECURITY.md
apc.config.example.json		apc.config.example.json
package-lock.json		package-lock.json
package.json		package.json

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