.NET 10 and Angular Signals Powered ‘Local-First’ Enterprise RAG (Vector Memory) Architecture

During Phase 3 of my .NET AI Architect Laboratory project development, I completely disabled external and costly cloud-based vector database dependencies (Vendor Lock-in). Instead, I established a Local-First Enterprise RAG infrastructure operating on .NET 10 core, a local SQLite layer, and Angular Signals.

The operations I have performed are as follows:

1. Cleaning Up Experimental Preview Package Dependencies
   
   I completely eliminated the experimental SemanticKernel.Connectors and VectorData.Abstractions preview packages from the project, which constantly caused version mismatches, unstable structures, and contained vulnerability warnings such as NU1904. I anchored the architecture to the framework’s own native, stable, and long-term supported enterprise packages.




2. Provider-Agnostic Embedding Substrate
   
   I wrote a pure C# wrapper called GoogleEmbeddingGenerator, abstracting Microsoft’s new enterprise AI standards (Microsoft.Extensions.AI) alongside Google’s official GenAI SDK.

I dynamically cast the high-dimensional double[] arrays produced by the Gemini text-embedding-004 model down to the float[] vectors expected by .NET interfaces.

Architectural Gain: I provided the full flexibility to transition to OpenAI or a completely local LLM model (Ollama/Llama, etc.) in the upcoming stages by simply changing the IoC (DI) registry inside Program.cs, without touching a single line of the core endpoint architecture.

1. Zero-Dependency Pure C# Cosine Similarity Engine
   To calculate the semantic proximity between vectors, I created zero dependencies on any heavy external mathematical libraries or third-party Python services. I coded a memory-friendly and high-performance cosine similarity matrix running directly on .NET core:

public static float CosineSimilarity(float[] vectorA, float[] vectorB)

{

if (vectorA.Length != vectorB.Length)

throw new ArgumentException("Vectors must have the same identical dimensions.");

float dotProduct = 0.0f, normA = 0.0f, normB = 0.0f;

for (int i = 0; i < vectorA.Length; i++)

{

dotProduct += vectorA[i] * vectorB[i];

normA += vectorA[i] * vectorA[i];

normB += vectorB[i] * vectorB[i];

}

return (normA == 0.0f || normB == 0.0f) ? 0.0f : dotProduct / ((float)Math.Sqrt(normA) * (float)Math.Sqrt(normB));

}

1. Deterministic Deduplication Against Data Inflation
   
   To prevent the SQLite table from inflating in case identical code blocks or files are added back-to-back into the system, I established a deterministic Base64 path-hashing mechanism inside the Angular frontend layer (memory-dashboard.component.ts) based on the file path. By ensuring a strictly unique and definite Id is generated for each file content, I triggered the SQLite native ON CONFLICT(Id) DO UPDATE constraint and completely zeroed out the duplicate row inflation within the database.




2. Knowledge-Augmented Agency Flow
   
   I integrated this created local vector memory with our autonomous multi-tool agent (/api/architect/inspect-autonomous). When the agent receives an architectural analysis task, it fires a query to this local SQLite vector layer in the background before directly scanning physical files on the disk. For example, when a user gives a general objective like “review frontend access ports,” our semantic search engine fetches the unmentioned CORS configuration code snippet from local memory and injects it into the agent’s real-time system context (Prompt). The agent generates decisions fully armed with localized enterprise domain experience.

🖥️ Dashboard RAG Panel Preview

The live screen artifact of the integrated RAG panel functions as follows:

Makale içeriği

1. Reactive Management Board: Angular Signals & Tailwind UI
   I visualized this entire local vector stream using Angular’s reactive Signals architecture and a dark-themed Tailwind CSS v3 interface. Driven by a single reactive state flag, the system seamlessly toggles between the Code Analyzer room and the Knowledge RAG room with zero latency, converting the entire control flow into a single cockpit.

🔗 Explore the Code

The next step following the completion of Phase 3: Developing the Automatic Code Ingestion Pipeline (Phase 4), which will automatically track modified code in the background and update local memory on the fly.

👉 GitHub Repository: github.com/muratsuzen/dotnet-ai-lab

The models themselves are just engines we rent; the true value lies in the architectural substrate, the context, and the documentation we build around them. This lab is my permanent digital logbook of that journey.