SwiftAgent: developer tool for Hermes Agent

Swift package that embeds Hermes Agent, CPython and an iSH shell inside an iOS app

What SwiftAgent does

SwiftAgent runs Hermes in process inside an iOS app. It embeds CPython, bundles Hermes and its Python dependencies, and exposes a Swift API for creating an agent, sending messages, streaming events and managing sessions. A HermesAgentConfiguration such as the OpenAI helper takes an API key and model, and agent.send returns a response while delivering events to a callback. The agent gets a workspace with file read and write tools that work across the iOS host filesystem and the iSH workspace, plus shell commands through an embedded iSH.

The app bundle is expected to hold a Python payload at PythonApp/hermes. A Run Script build phase calls swiftagent-install-hermes.sh, which fetches the pinned Hermes release if needed, stages platform-specific Python packages, installs the Python stdlib and converts native extension modules into signed app frameworks. The package also includes a sample iOS chat app, mock shell and model providers for tests, an optional local MLX provider proof of concept, and an Apple Foundation Models experiment for iOS 26+.

Key features

High-level Swift API for creating an agent, sending messages, streaming events and managing sessions
Embedded CPython with Hermes and its dependencies bundled
iSH-backed shell and file tools inside an app workspace
Build script that stages a pinned Hermes release and signs native extensions as frameworks
Sample iOS chat app and mock providers for tests
Optional add-on packages for local MLX models and Apple Foundation Models

When to use it

Building an iOS chat app whose agent is Hermes running inside the app
Streaming agent events into a SwiftUI interface
Trying on-device inference with MLX or Apple Foundation Models behind the same agent facade

Who it is for: iOS developers who want to ship Hermes Agent inside a native app instead of calling a remote server.

How it fits with Hermes Agent

Embeds Hermes Agent as its first supported runtime, running it in process; Hermes stays MIT-licensed and attributed to its upstream project.

How to install SwiftAgent

These commands are copied from the project's README. Check the repository for the latest steps before you run them.

.package(url: "https://github.com/achimala/SwiftAgent", branch: "main")
set -euo pipefail
"${BUILD_DIR%/Build/*}/SourcePackages/checkouts/SwiftAgent/Scripts/swiftagent-install-hermes.sh"

Requirements: An iOS app using Swift Package Manager; the Apple Foundation Models experiment needs iOS 26+

Note: The local MLX provider is described as a proof of concept and the Apple Foundation Models provider as an experiment.

FAQ

What is SwiftAgent?

SwiftAgent is a Swift package that embeds an AI agent runtime inside an iOS app. Its first supported runtime is Hermes Agent, bundled with CPython and run in process.

How do I install SwiftAgent?

Add the package with Swift Package Manager using the GitHub URL on the main branch, then add the SwiftAgent product to your app target. Also add a Run Script build phase that calls Scripts/swiftagent-install-hermes.sh.

Is SwiftAgent free and open source?

Yes. SwiftAgent is licensed under GPLv3 because its embedded iSH dependency is GPLv3. Hermes Agent itself is MIT-licensed and attributed to its upstream project.