Most RAG is unreliable problems don’t start at retrieval.
They start before retrieval.
Right at the beginning:
- the text comes in messy
- the same content gets ingested twice
- headings vanish
- chunks change every rebuild
- metadata is missing
- nobody can trace answers back to source
Then we blame the model.
But the pipeline is leaking. 🔥
The short answer
Yes, tools can automate ingestion + chunking reliably, but only if you treat it like a production pipeline, not a one-time script.
Reliable means:
- the same input produces the same chunks
- chunks have stable IDs
- every chunk has a clear source + section
- you can debug what changed and why
Why ingestion + chunking breaks so many systems
Because real-world inputs are chaotic.
A typical “knowledge set” is not clean text. It’s:
- PDFs with headers/footers repeated on every page
- docs with messy formatting
- copied Slack threads
- tables that turn into word soup
- repeated content across sources
If you chunk this blindly, your vector DB becomes a junk drawer.
And retrieval becomes:
- noisy
- duplicated
- inconsistent
- hard to debug
A real example: one pipeline run (simple version)
Imagine you ingest:
- 1 PDF spec
- 1 Notion export
- 1 Slack thread copy-paste
- 1 README
What often happens:
- duplicate chunks appear
- headings get lost
- long sections stay too long
- tiny sections become useless
- you can’t tell where a chunk came from later
What a reliable automated run does instead:
- Ingest: pull text in
- Clean: normalize spacing, remove junk characters
- Preserve structure: keep headings and lists
- Deduplicate: remove repeated headers/footers + near-duplicates
- Chunk with fixed rules: structure first, then size
- Attach metadata: source, section, timestamp, chunk index
- Generate stable IDs: so you can compare runs
- Log the run: docs in, chunks out, duplicates removed
That’s the difference between a “demo” and something you can trust.
The rule that changed everything for me
- Chunk by structure first.
- Then chunk by size.
Meaning:
- split by headings/sections first
- only then enforce chunk size limits
This keeps meaning together.
It stops random split in the middle of a key point problems.
Reliable ingestion + chunking checklist (copy/paste)
If you only take one thing from this post, take this checklist:
✅ Ingestion checklist
- Normalize whitespace and line breaks
- Normalize unicode (weird quotes, hidden chars)
- Remove repeated headers/footers in PDFs
- Preserve headings and bullet lists
- Keep code blocks intact (don’t smash formatting)
- Strip empty lines that add noise
✅ Chunking checklist
- Chunk by headings first (structure-aware)
- Enforce a max size (don’t make mega-chunks)
- Use overlap only when you can explain why
- Add chunk index (chunk_index) per source section
- Add stable IDs (doc_id + section_id + chunk_index)
✅ Metadata checklist (do not skip)
- source_type (pdf, doc, slack, repo, etc.)
- source_name (file name / page / channel)
- section_title (heading name)
- created_at (ingestion run time)
- chunk_index
- stable_chunk_id
✅ Run summary checklist (for debugging)
- docs ingested count
- total chunks created
- duplicates removed
- average chunk length
- errors/warnings per source
The 4 most common failure modes (and easy fixes)
1) My answers change every rebuild
Symptom: chunk count changes wildly, IDs don’t match
Fix: stable chunking rules + stable IDs + store a run summary
2) Retrieval feels random
Symptom: top results are intros, repeated text, or irrelevant fluff
Fix: dedupe + remove boilerplate headers/footers + chunk by headings
3) The model misses key details
Symptom: answers ignore important sections buried inside huge chunks
Fix: smaller chunks in dense areas (APIs, requirements), structure-first chunking
4) I can’t trace where the answer came from
Symptom: you can’t cite the section/page reliably
Fix: enforce metadata on every chunk (no metadata = reject the chunk)
A simple Before vs After mental model
Before:
Sources → some text → random chunks → vector DB → 🤷
After:
Sources → normalize → preserve structure → fixed chunk rules → metadata + stable IDs → store + logs → ✅ repeatable
Want to automate the boring parts of ingestion + chunking in minutes? Try HuTouch
FAQ (real questions people ask)
What chunk size should I use?
Start with a moderate size and test retrieval quality. The key is not the perfect number, it’s keeping it consistent and structure-aware.
Should I chunk by tokens or by headings?
Headings first. Tokens/length second. Headings keep meaning together.
How much overlap should I use?
Use small overlap only if you have a reason (like keeping a definition with its next paragraph). Too much overlap creates duplicates.
What about PDFs with tables?
Tables are tricky. If tables matter, extract them carefully or store them separately in a structured form instead of letting them turn into messy text.
How do I detect ingestion drift?
Track: chunks count, duplicate rate, and how many stable IDs matched the previous run.
What metadata matters most?
Source + section + stable ID. Without these, debugging becomes guesswork.
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