Sir Thaddeus

Privacy-first, permission-based local AI copilot for Windows.

Local-First AI Copilot for Windows

Sir Thaddeus runs on your machine.

Sir Thaddeus is a local AI assistant for Windows built for people who want useful AI without giving up control. It connects to local language models (for example, LM Studio), uses permission-based tool access, and keeps execution visible to the operator.

No telemetry by default. No silent background autonomy. No hidden actions.

If it acts, you see it. If you press STOP, it stops.

Documentation

Why Sir Thaddeus?

Most everyday AI tasks do not need a massive cloud model.

They need something that is:

Private
Reliable
Fast enough on modest hardware
Simple to run
Respectful of user boundaries

Sir Thaddeus lowers the barrier to entry for local AI on Windows while keeping the user in charge.

What It Feels Like to Use

Hold the push-to-talk hotkey and say:

"When is the local grocery store open?"

Before doing anything, Sir Thaddeus proposes the next step. You can see:

What access is requested
Why it is needed
How long the permission lasts

You approve. It runs. You get the result. Permission expires.

That same interaction model applies throughout the runtime:

Nothing runs silently
Nothing lingers in the background without approval
Every important action is recorded locally

Sir Thaddeus desktop UI showing permission-based local AI workflow

Features

Voice and Interface

Push-to-talk voice input with release-to-send behavior
Command palette for keyboard-first workflows
Global STOP kill switch to halt active execution
Tray-first Windows experience with local desktop controls

Local AI Runtime

Local LLM integration through LM Studio and OpenAI-compatible endpoints
Reasoning pipeline for breaking down logic questions step by step
Small-model support with routing assistance for better tool use
Supported document formats: PDF, DOCX, XLSX, CSV, RTF, Markdown, and plain text
In-memory result caching with configurable TTLs for web search, weather, and location data
Conversation-scoped memory retrieval for better continuity across multi-turn chats
Automatic history persistence for chat and briefing context in memory-backed flows

Permissioned Tooling via MCP

Web search and browser actions
Screen reading and active-window context
Read-only file listing and reading with limits
Clipboard read/write for seamless copy/paste integration
Allowlisted system actions
Built-in utilities for math, conversions, and structured lookups

Trust and Safety

Explicit permission prompts before tool execution
Time-boxed permission tokens
Local audit logging
Fail-closed behavior when something goes sideways
Tool budgets to prevent runaway loops and token burn

Optional Connected Services

Background watchers for website changes
Local notifications for monitored events

Quick Start

No cloud account required.

Go to the Releases page
Download the latest release ZIP
Unzip the archive
Run SirThaddeus.exe
Windows SmartScreen may appear. If so, choose More Info -> Run Anyway
Start your local model runner
Tested primarily with LM Studio
Complete first-run setup inside the app

That is it.

Headless Runtime (MVP)

A terminal entry point now exists for chat-first runs:

dotnet run --project apps/headless-runtime/SirThaddeus.HeadlessRuntime

Convenience launch scripts are available:

# Windows PowerShell
./dev/terminal.ps1

# Linux/macOS shell
./dev/terminal.sh
# (or: bash ./dev/terminal.sh)

Commands:

/help
/reset
/tools
/whoami
/quickstart
/exit

Tooling in headless mode is optional:

dotnet run --project apps/headless-runtime/SirThaddeus.HeadlessRuntime -- --tools

MCP now has a split tool model:

Core tools run cross-platform (net10.0)
Windows-only tools (screen capture / OCR) load only on Windows

Runtime API composition has also been modularized into focused endpoint groups
(core, memory, runs, profiles, personalities) to reduce regression risk
and improve production maintainability.

Changelog

See CHANGELOG.md for release notes and recent updates.

Core Principles

1. You are in control

Sir Thaddeus proposes actions. You approve them.

2. Nothing runs silently

If it acts, you can see it.

3. STOP always works

The kill switch revokes permissions and halts execution immediately.

Sir Thaddeus is not designed to replace your judgment. It is designed to extend your capability without taking away your agency.

Architecture

Sir Thaddeus uses a five-layer architecture that separates loop control, interface, model access, tools, and voice runtime.

Execution loop: propose -> validate -> execute -> observe -> verify -> repair -> repeat

flowchart LR
  subgraph loop [Layer 1: Loop - packages/agent]
    Loop[Bounded Agent Loop]
    Context[Run Context and History]
    Router[Intent Router]
    Gate[Policy Gate]
    Validate[Action and Completion Validation]
    Repair[Targeted Repair]
  end

  subgraph frontend [Layer 2: Interface - apps/ui-avalonia + apps/headless-runtime]
    Tray[System Tray]
    Overlay[Avalonia UI]
    PTT[Audio Input]
    Playback[Audio Playback]
    Palette[Command Palette]
  end

  subgraph model [Layer 3: Model - packages/llm-client]
    LmStudio[LM Studio / OpenAI-compatible]
  end

  subgraph tools [Layer 4: Tools - apps/mcp-server + packages/memory + memory-sqlite]
    Server[MCP Server - stdio]
    Toolset[Browser / File / System / Screen / WebSearch / Weather / Utilities]
    Memory[SQLite Memory and Retrieval]
  end

  subgraph voice [Layer 5: Voice - apps/voice-host + voice-backend]
    VoiceHost[VoiceHost Proxy]
    VoiceBackend[Voice Backend - Python]
    VoiceBackend --> VoiceHost
  end

  PTT -->|audio buffer| VoiceHost
  VoiceHost -->|transcribed text| Loop
  Palette -->|typed request| Loop

  Loop --> Router --> Gate
  Gate -->|allowed tools + budgets| Loop

  Loop -->|model prompt| LmStudio
  LmStudio -->|tool_calls / next action| Loop

  Loop --> Validate
  Validate -->|blocked/ok| Loop
  Validate -->|complete/partial/missing| Repair
  Repair -->|targeted follow-up| Loop

  Loop -->|tools/call| Server
  Server --> Toolset
  Server --> Memory
  Server -->|tool result| Loop

  Loop -->|final text| VoiceHost
  VoiceHost -->|audio stream| Playback

  Loop -->|events| Overlay
  Tray --> Overlay

Layer Responsibilities

Layer	Project(s)	Responsibility	Talks to
Layer 1: Loop	`packages/agent`	Route, gate, validate, repair, complete	Interface, Model, Tools, Voice
Layer 2: Interface	`apps/ui-avalonia`, `apps/headless-runtime`	Avalonia UI + terminal runtime entry points	Loop, Voice
Layer 3: Model	`packages/llm-client`	OpenAI-style model calls and embeddings	LM Studio, Loop
Layer 4: Tools	`apps/mcp-server`, `packages/memory`, `packages/memory-sqlite`	MCP tools plus local memory retrieval/storage	Loop
Layer 5: Voice	`apps/voice-host`, `apps/voice-backend`	Local ASR and TTS transport/runtime	Interface, Loop

Project Structure

sir-thaddeus/
|-- apps/
|   |-- ui-avalonia/
|   |-- headless-runtime/
|   |-- voice-host/
|   |-- voice-backend/
|   `-- mcp-server/
|-- assets/
|-- packages/
|-- tests/
|-- tools/
|-- Microsoft/
`-- project-notes/

Development

Prerequisites

.NET 10.0 SDK
(Optional) LM Studio or any OpenAI-compatible local model server
(Optional) SearXNG for local web search (bundled setup available)

Build

dotnet build SirThaddeus.sln

Test

dotnet test SirThaddeus.sln

Run (headless)

dotnet run --project apps/headless-runtime/SirThaddeus.HeadlessRuntime

Run (Avalonia UI)

dotnet run --project apps/ui-avalonia/SirThaddeus.UI.Avalonia

Technical Notes

Tested primarily with LM Studio and smaller local models
Other local runtimes may work, but support may vary
Smaller reasoning models can take longer to respond, especially in deeper thinking modes
The runtime is designed around permissioned execution, local visibility, and practical reliability

Who This Is For

Sir Thaddeus is for:

Developers exploring local AI tooling
Privacy-conscious users who want AI on Windows without telemetry
Builders interested in MCP architecture, tool routing, and permissioned agents
Anyone who wants an AI copilot they can actually control

It is not intended to be an unbounded autonomous agent that runs freely on your machine.

License

Licensed under Apache 2.0. See LICENSE for details.

sir-thaddeus