Refactored · Active development

Build the agent system.
Run it locally.

OpenCaddis is an open-source .NET workspace for creating FabrCore agents, developing add-ons with managed Agent Skills, and running everything locally through the Surface command center—all from one app.

Explore the current project View source
Local server AI add-on builder Managed Agent Skills MIT licensed
OpenCaddis character
Server · Builder · App
The current architecture

One workflow, three focused projects

The refactor separates operating the system, hosting the runtime, and building extensions. Each project has one clear job.

01

OpenCaddis.App

The Windows control app. Configure models, run either host mode, create agents from the live FabrCore registry, manage Builder workspaces, and open Surface without assembling the host by hand.

  • .NET MAUI desktop shell
  • Separate runtime and builder configuration
  • Registry-driven agent creation
  • Embedded Surface experience
App documentation
02

OpenCaddis.Server

A local FabrCore host with the Surface command center. It exposes agent discovery and creation APIs, accepts protected Harness Skill packages, discovers compiled add-ons, and stays on a loopback address.

  • FabrCore Host and Surface
  • Agent registry, creation, chat, and diagnostics
  • Protected principal-scoped Skill publishing
  • Collectible add-on assembly loading
  • Local cloud-configuration client
Server documentation
03

OpenCaddis.Server.Builder

A development host that provisions a dedicated Harness coding agent for each .NET project. Every agent gets the bundled FabrCore skill library, a durable todo loop, Roslyn insight, scoped editing, and controlled .NET CLI operations.

  • Project-scoped FabrCore Harness agents
  • Exact-version managed Agent Skills
  • Roslyn semantic inspection and diagnostics
  • Controlled filesystem and .NET CLI tools
  • Release build and add-on publishing
Builder documentation
The development loop

From source idea to a running add-on

OpenCaddis turns add-on development into a visible, local workflow. The builder and runtime stay separate so development tools are not loaded into the server that runs your agents.

See the architecture
1
Configure

Save a valid model and API key for Server and Server Builder in OpenCaddis.App.

2
Create

Use the running host registry to create an agent with its type, model, prompt, plugins, tools, and Surface visibility.

3
Build with Skills

Select a .NET project. OpenCaddis publishes its exact-version FabrCore Skills and provisions a todo-driven Harness coding agent.

4
Publish

The project agent restores, builds, tests, and copies the primary release DLL to the configured add-on directory.

5
Run

Start or restart OpenCaddis Server to discover the compiled assembly and use the resulting agents in Surface.

What exists today

A source-first foundation under active development

Windows .NET MAUI control app
Local FabrCore Server and Surface
Separate Server Builder mode
Registry-driven agent creation
Harness coding agents with managed Skills
Add-on assembly discovery and reload
Project status

OpenCaddis is not being presented as a finished packaged product yet. The repository is the authoritative source while the Server, Builder, and App workflow continues to mature.

Follow development on GitHub Build from source
Built on FabrCore

A focused workspace on a distributed agent foundation

FabrCore supplies the .NET 10 agent host, Harness, Agent Skills, SDK, messaging, tools, and Surface UI. OpenCaddis adds the desktop workflow for creating agents and building, publishing, loading, and operating your own add-ons.

Read FabrCore docs FabrCore source How Builder Skills work Understand add-ons

Start with the current source

See exactly what is implemented, how the three projects fit together, and where OpenCaddis is heading.

Read the docs Browse the repository