Kuroko (黒子) – Stealth Interview Co-Pilot

To exist without being seen. To help without being heard.

Kuroko is a high-performance, stealth-focused desktop assistant designed for technical interviews. It leverages local hardware for audio processing and RAG (Retrieval Augmented Generation) while orchestrating cloud-based LLMs for intelligence, ensuring privacy, low latency, and zero detection.

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🎥 Demo

The interface visible above is seen only by the user. To an interviewer viewing your screen via Zoom, Teams, or OBS, the desktop appears completely empty.

(Click the image to watch the full demo on YouTube)

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🧠 Engineering Methodology

This project was built on three core pillars:

• Invisibility
• Latency
• Privacy

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1. Stealth Architecture (Anti-Detection)

Unlike browser extensions or meeting bots, Kuroko runs entirely outside the meeting context.

Visual Invisibility

• Uses the Win32 SetWindowDisplayAffinity API with WDA_EXCLUDEFROMCAPTURE
• Renders the UI strictly to the user's physical monitor
• Bypasses the DWM bitstream sent to screen-sharing software (Zoom, Teams, OBS)
• Toggleable for OBS recording

Process Camouflage

• Uses WS_EX_TOOLWINDOW extended window styles
• Hides the application from the Taskbar and Task Manager “Apps”
• Masquerades as a background system process

Decoy Strategy

• Configurable Masquerade Mode
• Alters process title and icon at runtime
• Examples: Calculator, Runtime Broker
• Designed to evade manual inspection

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2. Latency Optimization (The <200ms Goal)

Speed is non-negotiable. Every millisecond was engineered out.

Producer–Consumer Audio Pipeline

• Replaced standard event loops with System.Threading.Channels
• Listener (Producer) slices audio via VAD and pushes to an unbounded queue
• Composer (Consumer) transcribes in parallel
• Guarantees zero audio loss and minimal blocking

Network Tuning

• Enforces HTTP/2
• Maintains warmed-up connection pools via SocketsHttpHandler
• Eliminates repeated SSL/TLS handshake overhead

Streaming Pipeline

• Uses IAsyncEnumerable with Server-Sent Events (SSE)
• Tokens render instantly as they arrive
• No waiting for full completion

SIMD Vector Search

• Uses System.Numerics.Tensors
• Hardware-accelerated cosine similarity
• Instant retrieval from the local RAG database

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3. Local-First Privacy (RAG)

Sensitive data never permanently leaves the machine.

Ingestion

• PdfPig extracts text from PDF resumes and CVs

Vector Store

• Chunked and stored in a local SQLite database

Retrieval

• Embeddings generated on demand
• Only relevant chunks are sent to the cloud LLM
• Full resume is never exposed to provider training data

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🛠 Tech Stack

• Language: C# / .NET 10
• UI Framework: WPF (Windows Presentation Foundation)
• Audio Engine: NAudio (WASAPI Loopback Capture)
• Transcription: Whisper.net (local C++ bindings)
• AI Orchestration: Semantic Kernel / Custom OpenRouter Client
• Database: SQLite (with vector logic)

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🚀 Getting Started

Prerequisites

• OS: Windows 10/11 (x64)
• Runtime: .NET 10 SDK
• Hardware: Microphone + Speakers Headphones recommended to prevent feedback

Installation

git clone https://github.com/hyowonbernabe/Kuroko.git

1. Open Kuroko.sln in Visual Studio
2. Restore NuGet packages
3. Create a .env file in the root directory
4. Build and Run (Ctrl + F5)

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⚙ Configuration (.env)

Create a .env file in the project root:

OPENROUTER_API_KEY=sk-or-v1-your-key-here
OPENROUTER_MODEL=google/gemma-3-27b-it:free

# Window Behavior
WINDOW_TOPMOST=True
DEEP_STEALTH=False
SCREEN_SHARE_PROTECTION=True

# Hotkeys (Modifiers + Key)
HOTKEY_TRIGGER_TXT=Alt + S
HOTKEY_PANIC_TXT=Alt + Q
HOTKEY_CLEAR_TXT=Alt + C

# Masquerade (Optional)
DECOY_TITLE=Host Process
DECOY_ICON=

# Persona (System Prompt)
SYSTEM_PROMPT=You are Kuroko, an invisible interview assistant...

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📦 Deployment (Building the Executable)

To deploy Kuroko as a standalone .exe with no installer:

dotnet publish Kuroko.UI/Kuroko.UI.csproj \
  -c Release \
  -r win-x64 \
  --self-contained true \
  -p:PublishSingleFile=true \
  -p:IncludeNativeLibrariesForSelfExtract=true

Output location:

\bin\Release\net9.0-windows\win-x64\publish\

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🎮 Usage Guide

1. Initialization

• Launch Kuroko
• Appears as a small toolbar at the bottom-left
• Click INITIALIZE
• Status changes to ACTIVE

Ensure audio is playing or speaking to verify capture.

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2. Knowledge Base (RAG)

• Open SYSTEM CONFIG → KNOWLEDGE BASE
• Upload your Resume or Technical CV (PDF)
• Data is parsed, chunked, and stored in kuroko_rag.db
• Files can be managed or wiped at any time

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3. Interview Trigger

• Trigger (Alt + S): Capture context and stream answers
• Clear Context (Alt + C): Reset transcription buffer
• AI Insight: Markdown-rendered floating overlay

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4. Customization

• Persona: Edit the System Prompt to control behavior

• Stealth:

  • Toggle Deep Stealth to hide from Taskbar
  • Toggle Screen Share Protection for OBS or Zoom

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5. Panic Mode

• Press Alt + Q
• Immediately terminates the application process

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🛡 Disclaimer

This software is intended for educational purposes and personal assistance only. Users are responsible for complying with platform terms of service and any agreements they have entered into.