Incomplete Context Assembly

The Problem

Retrieved chunks provide partial information, missing critical details needed for complete answers, causing fragmented or misleading responses.

Symptoms

• ❌ Answer covers part of topic, omits key info

• ❌ Multi-step procedures incomplete

• ❌ Missing prerequisites or warnings

• ❌ Important context cut off mid-explanation

• ❌ Users must ask follow-up for basics

Real-World Example

Documentation procedure (full):
1. Backup your data (CRITICAL)
2. Run migration script
3. Verify results
4. Restore if errors occur

Retrieved chunks:
→ Chunk 1: "Run migration script: npm run migrate"
→ Chunk 2: "Verify with: npm run verify"

Missing: Step 1 (backup) and Step 4 (restore)

AI response: "Run npm run migrate then npm run verify"

User runs it → Data loss (no backup step)

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Deep Technical Analysis

Chunking Boundary Issues

Procedure Split Across Chunks:

Document:
"Prerequisites: Install Node.js 18+
Steps:
1. npm install
2. npm run setup
..."

If chunked at 500 tokens:
→ Chunk A: Prerequisites + steps 1-3
→ Chunk B: Steps 4-6

Query matches Step 5:
→ Only Chunk B retrieved
→ Missing prerequisites from Chunk A
→ Incomplete procedure

Context Window Limitations:

Retrieved 10 chunks:
→ 8,000 tokens total
→ Context window: 4,000 tokens
→ Must truncate

Last 3 chunks dropped:
→ Contain critical warnings
→ AI doesn't see them
→ Incomplete answer

Retrieval K Tuning

Too Few Chunks:

K=3 (retrieve top 3 chunks):
→ May capture main concept
→ But miss supporting details
→ Incomplete picture

Example:
→ Chunk 1: API authentication basics
→ Chunk 2: OAuth flow
→ Chunk 3: Token refresh
→ Missing (K=3): Rate limits, error codes, best practices

Optimal K:

Testing shows:
→ K=5-10 for simple factual queries
→ K=10-20 for complex explanatory queries
→ K=20+ for comprehensive procedures

But: Larger K = more tokens, higher cost

Hierarchical Information

Parent-Child Relationships:

Document structure:
Section: "Database Setup"
  - Subsection: "PostgreSQL"
    - Step: "Create user"
    - Step: "Grant permissions"

Retrieval matches "Grant permissions":
→ Retrieves only that step
→ Missing parent context (PostgreSQL setup)
→ User doesn't know which DB this applies to

Context Expansion:

Strategy: Retrieve parent sections too
→ Match found in subsection
→ Also retrieve parent section
→ Provides broader context
→ More complete answer

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How to Solve

Increase retrieval K (test 10-20 chunks) + implement context expansion (retrieve parent sections) + use hierarchical chunking with parent-child links + apply reranking to surface most complete chunks + adjust chunk size to capture complete procedures + use sliding window overlap (10-15%) to avoid boundary splits. See Context Completeness.