Port42 - AI Companions That Build Tools on Your Mac

TL;DR

TL;DR: Port42 is a native Mac app where AI companions build interactive UIs mid-conversation and act on your machine through a unified API — no cloud dependency, MIT open source.

Source and Accuracy Notes

• Product: https://port42.ai
• GitHub: https://github.com/gordonmattey/port42-native
• Author: gordonmattey (Show HN, 5 points, Jun 2026)

What Is Port42?

Port42 is a native macOS application that redefines how humans and AI agents collaborate on a single machine. Instead of a chat interface that answers questions, Port42 hosts multiple AI companions that can both build interactive software and execute actions on your Mac in real time.

The core insight: computing is stuck in windows, but conversation is where intent lives. Port42 bridges both by giving companions a “Ports” API that exposes your machine’s capabilities — clipboard, screen capture, terminal, filesystem, browser, audio, AppleScript — and renders results as live HTML/CSS/JS apps that pop up inline during conversation.

The result: an AI companion can build you a dashboard, a file browser, or a monitoring tool mid-conversation and have it running as a floating window on your desktop — then act on your machine through the same API to gather the data that populates it.

How Port42 Works

The Ports API

Ports are the bridge between AI companions and your Mac. One API, two surfaces:

Visual surface: Companions render live HTML/CSS/JS apps inline in the conversation or pop them out into floating windows. These apps dock, resize, and persist across sessions. A companion building a dashboard mid-conversation is not hypothetical — it is the core interaction model.

Action surface: The same API lets companions execute actions: run terminal commands, read/write the clipboard, capture screenshots, navigate the filesystem, control a headless browser, trigger AppleScript/JXA automation, and synthesize speech. The model decides what to call and chains calls together.

Example interactions:

"Run my tests." → companion executes test suite, reports results inline
"Take a screenshot and describe what you see." → screen capture + vision analysis
"Read my clipboard, translate it, copy it back." → clipboard → LLM translation → clipboard write

No Cloud Dependency

Port42 runs entirely on-device. E2E encryption (AES-256-GCM) secures data. The app requires a Claude subscription (via Claude Code OAuth) or your own Anthropic API key. No data leaves your machine unless you explicitly configure cloud hooks.

Practical Evaluation Checklist

• Native macOS app, MIT open source
• AI companions build live UI surfaces mid-conversation
• Unified Ports API exposes: terminal, filesystem, clipboard, screen capture, browser, AppleScript, TTS
• Floating windows persist across sessions
• Works with Claude Code OAuth or custom Anthropic API key
• E2E encrypted, no mandatory cloud dependency
• Requires Mac (native app)

Security Notes

Permission prompts are requested per companion, per conversation. The app does not make decisions about what actions to take without consent — it presents the plan and waits for you to approve. AES-256-GCM encryption protects data at rest and in transit.

Because companions execute code on your machine (terminal commands, AppleScript), grant permissions thoughtfully. The permission model is still maturing — v0.5.1 as of June 2026.

FAQ

Q: What models does Port42 support?

A: Currently requires Claude via Claude Code OAuth (subscription) or a direct Anthropic API key. The app is architected around Claude Code’s tool-use paradigm, which maps naturally to the Ports API.

Q: Is this different from just using Claude Code in a terminal?

A: Yes. Claude Code in a terminal produces text output. Port42 companions build live UI surfaces that render inline, pop out as floating windows, and persist — transforming conversation output into interactive software. The Ports API also exposes capabilities (screen capture, clipboard, TTS, AppleScript) that a terminal session cannot easily orchestrate.

Q: Can I run this without an Anthropic API key?

A: Yes — the Claude Code OAuth option lets you use an existing Claude subscription without providing your own API key directly.

Q: Does this work on Linux or Windows?

A: No. Port42 is a native macOS application. The Ports API is Mac-specific (AppleScript, screen capture, Finder integration).

Q: How mature is this?

A: Version 0.5.1, 9 days old at launch. The core interaction model works, but there are rough edges. Not yet production-stable for mission-critical workflows.

Conclusion

Port42 is an experiment in what happens when an AI agent can both build software AND execute actions on your machine through the same API — not as separate concerns but as one unified interface. The live UI rendering is the killer feature: instead of describing a dashboard, the companion builds one. Instead of asking for a screenshot description, it takes one and shows you.

If you have a Mac and a Claude subscription, it is worth a weekend afternoon to try. The gap between “AI that talks” and “AI that acts and builds” is where Port42 lives — and it is genuinely different from every other AI assistant on the Mac platform right now.