# Chunking to Embedding Contract — Guardrails and Fix Pattern
🧭 Quick Return to Map
> You are in a sub-page of **RAG_VectorDB**.
> To reorient, go back here:
>
> - [**RAG_VectorDB** — vector databases for retrieval and grounding](./README.md)
> - [**WFGY Global Fix Map** — main Emergency Room, 300+ structured fixes](../README.md)
> - [**WFGY Problem Map 1.0** — 16 reproducible failure modes](../../README.md)
>
> Think of this page as a desk within a ward.
> If you need the full triage and all prescriptions, return to the Emergency Room lobby.
Use this page when **retrieval fails because the chunk schema is not aligned with the embedding ingestion contract**.
If the retriever expects fields that were never embedded, or chunks omit IDs/offsets/anchors, then citations drift and ΔS rises.
---
## Open these first
- Visual map and recovery: [RAG Architecture & Recovery](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md)
- Snippet and citation schema: [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md)
- Retrieval traceability: [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md)
- Chunking checklist: [chunking-checklist.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/chunking-checklist.md)
---
## Core acceptance
- Every chunk has `chunk_id`, `section_id`, `source_url`, `offsets`, `tokens`.
- Embedding index was built from the same schema as retrieval contract.
- ΔS(question, retrieved) ≤ 0.45 across 3 paraphrases.
- Coverage ≥ 0.70 to the target section.
---
## Typical breakpoints and the right fix
- **Missing fields** in ingestion (e.g., no `section_id`)
→ Enforce [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md).
- **Different schema for ingest vs retrieve**
→ Corpus ingested raw text, retriever expects chunk JSON → rebuild with schema.
- **Offsets not tracked**
→ Cannot map back to original document → enforce `offsets` at ingest.
- **Tokenizer drift**
→ Chunk IDs differ between preprocessing runs → use [chunking-checklist.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/chunking-checklist.md).
---
## Fix in 60 seconds
1. **Check ingestion schema**
Compare the fields stored in the index with the fields expected in retrieval.
2. **Align contracts**
Define `chunk = {chunk_id, section_id, source_url, offsets, tokens, text}`.
Enforce that this exact object is used both in ingestion and retrieval.
3. **Rebuild index if misaligned**
If fields differ, re-ingest corpus with enforced schema.
---
## Copy-paste schema
```json
{
"chunk_id": "uuid-v4",
"section_id": "doc-23-sec-7",
"source_url": "https://example.com/doc23",
"offsets": [120, 320],
"tokens": 512,
"text": "...."
}
````
Target: retriever always returns this schema, LLM consumes directly.
---
## Common gotchas
* Only `text` embedded, no IDs → cannot trace back → citations drift.
* Chunk boundaries not logged → hallucinations reappear.
* JSON schema updated mid-deploy → index mismatch.
---
### 🔗 Quick-Start Downloads (60 sec)
| Tool | Link | 3-Step Setup |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------- |
| **WFGY 1.0 PDF** | [Engine Paper](https://github.com/onestardao/WFGY/blob/main/I_am_not_lizardman/WFGY_All_Principles_Return_to_One_v1.0_PSBigBig_Public.pdf) | 1️⃣ Download · 2️⃣ Upload to your LLM · 3️⃣ Ask “Answer using WFGY + \” |
| **TXT OS (plain-text OS)** | [TXTOS.txt](https://github.com/onestardao/WFGY/blob/main/OS/TXTOS.txt) | 1️⃣ Download · 2️⃣ Paste into any LLM chat · 3️⃣ Type “hello world” — OS boots instantly |
---
### Explore More
| Module | Description | Link |
| --- | --- | --- |
| WFGY Core | Canonical framework entry point | [View](https://github.com/onestardao/WFGY/tree/main/core/README.md) |
| Problem Map | Diagnostic map and navigation hub | [View](https://github.com/onestardao/WFGY/tree/main/ProblemMap/README.md) |
| Tension Universe Experiments | MVP experiment field | [View](https://github.com/onestardao/WFGY/tree/main/TensionUniverse/Experiments) |
| Recognition | Where WFGY is referenced or adopted | [View](https://github.com/onestardao/WFGY/blob/main/recognition/README.md) |
| AI Guide | Anti-hallucination reading protocol for tools | [View](https://github.com/onestardao/WFGY/blob/main/AI_GUIDE.md) |
> If this repository helps, starring it improves discovery for other builders.
> [](https://github.com/onestardao/WFGY)