Table of Contents

RAG (Retrieval-Augmented Generation)

RAG lets the model answer questions based on your own documents by retrieving relevant chunks at query time.

Installation

dotnet add package Mythosia.AI.Rag

Quick Start

Use .WithRag() on any IAIService to enable RAG with a fluent API:

using Mythosia.AI.Rag;

var service = new AnthropicService(apiKey, http)
    .WithRag(rag => rag
        .AddDocument("manual.txt")
        .AddDocument("policy.txt")
    );

var response = await service.GetCompletionAsync("What is the refund policy?");

The documents are split, embedded, and stored automatically. At query time, the most relevant chunks are retrieved and injected into the prompt.

Adding Documents

Several source types are supported:

.WithRag(rag => rag
    .AddDocument("readme.txt")                    // local file
    .AddDocument("https://example.com/doc.txt")   // URL
    .AddText("Inline content can go here too.")   // raw string
)

Custom Embedding Provider

By default, RAG uses the service's own provider for embeddings. To use a dedicated embedding model:

using Mythosia.AI.Rag.Embeddings;

var embedder = new OpenAIEmbeddingProvider(apiKey, http, "text-embedding-3-small");

var service = new AnthropicService(apiKey, http)
    .WithRag(rag => rag
        .UseEmbeddingProvider(embedder)
        .AddDocument("knowledge-base.txt")
    );

Custom Vector Store

By default, an in-memory store is used. For production, plug in a persistent vector store:

dotnet add package Mythosia.VectorDb.Postgres

using Mythosia.VectorDb.Postgres;

var store = new PostgresStore(connectionString, embedDimension: 1536);

var service = new OpenAIService(apiKey, http)
    .WithRag(rag => rag
        .UseVectorStore(store)
        .AddDocument("large-corpus.txt")
    );

Query Options

Fine-tune retrieval behavior per query:

var options = new RagQueryOptions
{
    TopK = 5,           // number of chunks to retrieve
    ScoreThreshold = 0.7f  // minimum similarity score
};

var response = await service.GetCompletionAsync("Your question", ragOptions: options);

Next Steps

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