How do agentic RAG agents handle context window limits?

Agentic RAG agents must carefully manage LLM context windows—they can exceed limits when retrieving large documents across multiple loops.

Context management strategies:

1. Selective retrieval: Retrieve only k=3–5 results per query, not k=20. Agents rewrite queries to get more relevant results rather than retrieve everything.

2. Summarization in loops: After each retrieval, agent summarizes results before re-querying. Compresses context by 60–80% without losing information.

3. Document chunking: Store document chunks (256–512 tokens) in Milvus, not full documents. Agents retrieve multiple small chunks, stay within context.

4. Metadata-driven filtering: Constrain retrieval to specific documents upfront. If agent knows to look in "Q4_2025_reports", it narrows the search space.

5. Two-stage retrieval:

  • Stage 1: Dense search returns document IDs
  • Stage 2: Agent fetches only the relevant sections of those documents
  • Milvus returns metadata (doc_id, chunk_id) for lightweight filtering

6. Context budget per loop: Set a token limit per retrieval round. If approaching limit, agent uses summarization or stops looping.

Example: Agent answering “What are our top 3 supplier risks?” might loop 3 times:

  • Loop 1: Retrieve supplier profiles (100 tokens)
  • Loop 2: Retrieve risk assessments for top suppliers (150 tokens)
  • Loop 3: Retrieve mitigation strategies (120 tokens)
  • Total: 370 tokens, well within 4K–8K context windows

Design agentic workflows with context budgets. Milvus’s metadata and chunking support this natively.

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