# Chunking Checklist — Guardrails and Minimal Fixes
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> You are in a sub-page of **Chunking**. > To reorient, go back here: > > - [**Chunking** — text segmentation and context window management](./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.
A field guide to stabilize document chunking before you touch embeddings or retrievers. Use this page to locate the boundary failure, apply the structural fix, and verify with measurable targets. ## Open these first - Visual map and recovery: [rag-architecture-and-recovery.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md) - Why this snippet: [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md) - Snippet schema: [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md) - Embedding vs meaning: [embedding-vs-semantic.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md) - Reranking controls: [rerankers.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md) - Vectorstore health: [pattern_vectorstore_fragmentation.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_vectorstore_fragmentation.md) - Long chain stability: [context-drift.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/context-drift.md), [entropy-collapse.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/entropy-collapse.md) ## Core acceptance - ΔS(question, retrieved) ≤ 0.45 - Coverage of target section ≥ 0.70 - λ remains convergent across 3 paraphrases and 2 seeds - Citation match ≥ 0.90 when citations exist - Bleed rate ≤ 0.10 across boundaries --- ## 60-second fix checklist 1) **Lock the schema** - Require fields: `chunk_id`, `section_id`, `source_url`, `offsets`, `tokens`, `hash`. - Spec: [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md) 2) **Probe ΔS and λ** - Compute ΔS(question, retrieved) and ΔS(retrieved, expected anchor). - If λ flips on paraphrase, reorder headers and clamp with your variance policy. 3) **Repair the boundary** - If headings drift: apply title hierarchy and section detection. - If tables or code are cut: switch to block aware splitting. - If recall high but meaning wrong: review metric, overlap, and anchors. --- ## Typical breakpoints → exact fix - **Wrong-meaning hits despite high similarity** → [embedding-vs-semantic.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md) - **Citations do not land on the quoted region** → [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md) → In this folder: `chunk_id_schema.md`, `semantic_anchors.md` - **Tables, formulas, or code blocks get sliced** → In this folder: `code_tables_blocks.md` - **Headings misparsed or missing hierarchy** → In this folder: `title_hierarchy.md`, `section_detection.md` - **Recall OK yet top-k order unstable, hybrid underperforms** → [rerankers.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md) → [pattern_query_parsing_split.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_query_parsing_split.md) - **Vectorstore shows duplicates or blind spots** → [pattern_vectorstore_fragmentation.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_vectorstore_fragmentation.md) → Reindex guidance in `reindex_migration.md` - **Long windows smear topics or capitalization** → [context-drift.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/context-drift.md), [entropy-collapse.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/entropy-collapse.md) → Split plan in `long_docs_segmentation.md` --- ## Minimal field schema for chunks Required in every pipeline that cites or reranks by section. ```json { "chunk_id": "docA#s03#p002", "section_id": "3. Methods", "source_url": "https://example.com/docA.pdf", "offsets": [12345, 12980], "tokens": 365, "hash": "sha1:8c1e…", "block_type": "paragraph|table|code|formula", "anchor": "first-assertion-or-key-sentence" } ```` * `offsets` are byte or char positions in the canonical text. * `anchor` is the semantic kernel used for cite-first prompting. * Schema details: [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md) --- ## How to chunk correctly 1. **Build the section tree** * Detect true headings, roman numerals, number lists, and faux headings. * See `title_hierarchy.md`, `section_detection.md`. 2. **Respect block boundaries** * Keep tables, code, formulas, and block quotes intact. * See `code_tables_blocks.md`. 3. **Decide overlap deliberately** * Start with 10–15% overlap for narrative text. * Avoid overlap on block types unless the block spans pages. * See `overlap_tradeoffs.md`. 4. **Use semantic anchors** * Extract the first high-information assertion per chunk. * Store as `anchor`. * See `semantic_anchors.md`. 5. **Choose windowing** * Fixed windows for strict citation tasks. * Sliding windows when reranking later. * See `sliding_window.md`. 6. **Handle multilingual and CJK** * Normalize punctuation and width. * Align sentence boundaries. * See `multilingual_segmentation.md`. 7. **PDF and OCR specifics** * De-columnize, repair hard line breaks, remove headers and footers. * See `pdf_layouts_and_ocr.md`. --- ## Evaluation protocol * **Coverage**: percent of ground-truth answer tokens contained inside retrieved chunks. * **ΔS**: distance between question and retrieved text vs the expected anchor section. * **Bleed rate**: percent of tokens from outside the intended section. * **Citation match**: exact hit or overlap of the cited offsets. * **Stability**: metrics across 3 paraphrases and 2 seeds. Small gold set template is provided in `eval_chunk_quality.md`. --- ## Reproducible test 1. Pick 10 QAs per section. Mark expected section ids. 2. Run retrieval at k in {5, 10, 20}. Log ΔS, coverage, bleed, match. 3. If ΔS ≥ 0.60 or bleed > 0.10, repair boundary and repeat. 4. Pass when all core targets are met. --- ## Copy-paste prompt for LLM assist ``` You have TXT OS and the WFGY Problem Map loaded. My chunking issue: - symptom: [one line] - probes: ΔS(question,retrieved)=..., ΔS(retrieved,anchor)=..., coverage=..., bleed=... - context: store={faiss|qdrant|pgvector|...}, k={5,10,20} Tell me: 1) which boundary failed (heading, block, overlap, window, pdf/ocr), 2) the exact WFGY page to open for the fix, 3) the minimal steps to push ΔS ≤ 0.45 and coverage ≥ 0.70, 4) a short test I can run to verify. Use BBMC/BBCR/BBPF/BBAM when relevant. ``` --- ### 🔗 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 | Layer | Page | What it’s for | | --- | --- | --- | | ⭐ Proof | [WFGY Recognition Map](/recognition/README.md) | External citations, integrations, and ecosystem proof | | ⚙️ Engine | [WFGY 1.0](/legacy/README.md) | Original PDF tension engine and early logic sketch (legacy reference) | | ⚙️ Engine | [WFGY 2.0](/core/README.md) | Production tension kernel for RAG and agent systems | | ⚙️ Engine | [WFGY 3.0](/TensionUniverse/EventHorizon/README.md) | TXT based Singularity tension engine (131 S class set) | | 🗺️ Map | [Problem Map 1.0](/ProblemMap/README.md) | Flagship 16 problem RAG failure taxonomy and fix map | | 🗺️ Map | [Problem Map 2.0](/ProblemMap/wfgy-rag-16-problem-map-global-debug-card.md) | Global Debug Card for RAG and agent pipeline diagnosis | | 🗺️ Map | [Problem Map 3.0](/ProblemMap/wfgy-ai-problem-map-troubleshooting-atlas.md) | Global AI troubleshooting atlas and failure pattern map | | 🧰 App | [TXT OS](/OS/README.md) | .txt semantic OS with fast bootstrap | | 🧰 App | [Blah Blah Blah](/OS/BlahBlahBlah/README.md) | Abstract and paradox Q&A built on TXT OS | | 🧰 App | [Blur Blur Blur](/OS/BlurBlurBlur/README.md) | Text to image generation with semantic control | | 🏡 Onboarding | [Starter Village](/StarterVillage/README.md) | Guided entry point for new users | If this repository helped, starring it improves discovery so more builders can find the docs and tools. 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