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Context assembly

As explained in Machine Learning Platform Engineering

Context assembly is the organization, formatting, and combination of retrieved information into context suitable for a language model.

Context assembly transforms retrieved document chunks and a user query into structured context that a language model can process. It bridges semantic search and coherent prompt construction by formatting, deduplicating, and organizing retrieved information. section 12.2.5

A production-oriented assembly flow should:

  • Load the persistent vector index with the same embedding model, dimensions, normalization, and model version used during indexing. section 12.2.5
  • Expose retrieval through a standardized interface, then combine document contents with clear separators for prompt construction. section 12.2.5
  • Monitor reasoning paths, token allocation, context utilization, and failures across retrieval, assembly, and generation. section 12.4.4

Policy question prompt

For a question such as “What’s our vacation policy?”, assemble a prompt containing the relevant handbook sections followed by the user’s question: “Based on these policy sections: [chunk 1], [chunk 2], [chunk 3], answer: What’s our vacation policy?” section 12.2.5

Listing 12.10 RAG query processing with retrieval and context
query = "How do I rotate encryption keys?"  #1
docs = retriever.invoke(query)  #2
context = "\n\n".join( #3
    [doc.page_content for doc in docs])   #3

Shows the minimal retrieval-to-context operation: invoke the retriever, extract page content, and join documents into a single context string. section 12.2.5

How Machine Learning Platform Engineering covers it

How deep it goes
Explains formatting, deduplication, retrieval interfaces, embedding compatibility, and security trade-offs, while deferring more sophisticated assembly.
Examples
Uses a vacation-policy prompt and an encryption-key query assembled from retrieved document contents.
What it assumes
Assumes a prebuilt vector index, compatible embeddings, and a retrieval system.
What you can do after
Apply it via LangChain and FAISS to retrieve documents and construct model-ready context.
How it connects
Connects retrieval, RAG, prompt construction, vector indexes, embeddings, and observability.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Machine Learning Platform Engineering. The section links point to the parts of the book it draws on.