Models & Algorithms•January 7, 2026•KR

Query Planning Failures in Multi-hop RAG: Patterns and Solutions

You added Query Decomposition, but why does it still fail? Decomposition is just the beginning—the real problems emerge in Sequencing and Grounding.

Query Planning Failures in Multi-hop RAG: Patterns and Solutions

You added Query Decomposition, but why does it still fail? Decomposition is just the beginning—the real problems emerge in Sequencing and Grounding.

What is Query Planning?

Processing complex questions in Multi-hop RAG requires three stages:

Query Planning = Decomposition + Sequencing + Grounding

Stage	Role	Failure Symptom
Decomposition	Break complex query into sub-queries	Missing information or unnecessary searches
Sequencing	Determine sub-query execution order	Dependent queries run first and fail
Grounding	Match sub-queries to actual documents	Decomposition works but search returns 0 results

Most Multi-hop RAG failures occur in one of these three stages.

Failure Pattern #1: Decomposition Failures

1-A. Over-decomposition

python

query = "How did Tesla's stock react after they cut prices?"

# Over-decomposed result
decomposed = [
    "What kind of company is Tesla?",        # Unnecessary
    "What products does Tesla make?",         # Unnecessary
    "Did Tesla cut prices?",
    "When did Tesla cut prices?",
    "How much was the price cut?",
    "What is Tesla's current stock price?",   # Wrong timeframe
    "What caused the stock movement?"          # Too abstract
]

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