# Context Stitching and Window Joins: Guardrails and Fix Pattern
🧭 Quick Return to Map
> You are in a sub-page of **Reasoning**.
> To reorient, go back here:
>
> - [**Reasoning** — multi-step inference and symbolic proofs](./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.
Join long contexts without losing meaning. This page defines a stitch contract for multi window prompts and long documents, adds ΔS probes at joins, and gives a fast repair plan when answers break exactly at window boundaries.
---
## 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)
- Traceability and payload schema
→ [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md)
→ [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md)
- Ordering and meaning checks
→ [rerankers.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md)
→ [embedding-vs-semantic.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md)
- Reasoning stability and failure modes
→ [anchoring-and-bridge-proofs.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/anchoring-and-bridge-proofs.md)
→ [logic-collapse.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/logic-collapse.md)
→ [entropy-overload.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/entropy-overload.md)
- Chunking quality
→ [chunking-checklist.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/chunking-checklist.md)
---
## Symptoms
| Symptom | What you see |
|---|---|
| Boundary answers | Model answers correctly inside a window, fails right after the join |
| Duplicate facts | Repeated sentences across windows, tool loops on the overlap |
| Lost referent | “it / they / this” loses target at window start or end |
| Rerank flip at join | Top k order changes only at a boundary |
| Anchor drift | Citation before the join, none after the join |
| Coverage hole | Middle section of a long doc never appears in stitched set |
---
## Why joins fail
1) **No stitch contract**. Windows lack overlap and sequence identifiers.
2) **Tokenizer mismatch**. Window boundaries split tokens differently across tools.
3) **Ranking variance**. Each window retrieves independently without a stable tie break.
4) **Anchor loss**. Bridge steps cross a boundary without re citing the anchor.
5) **Context flooding**. Overlong windows raise entropy and bury anchors.
6) **Fragmentation**. Store keeps near duplicates that fight for the same rank.
---
## Acceptance targets
- ΔS(join_left, join_right) ≤ 0.45 for every boundary
- Coverage of target section across all windows ≥ 0.70
- λ remains convergent across three paraphrases and two seeds
- E_resonance flat at joins and flat across stitched plan
- Overlap per join 32 to 96 tokens, same casing and analyzer
---
## Fix in 60 seconds
1) **Add a stitch contract**
Every window must carry `doc_id, section_id, win_idx, win_hash, overlap_tokens, prev_id, next_id`.
See schema rules
→ [retrieval-traceability.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md)
→ [data-contracts.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md)
2) **Measure ΔS at each join**
Compute ΔS between the trailing overlap of window *i* and the leading overlap of window *i+1*.
If ΔS ≥ 0.60, rebuild the join or re chunk.
3) **Stabilize ordering**
Use a deterministic reranker with fixed analyzer and tie break by `(doc_id, section_id, win_idx)`.
→ [rerankers.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md)
4) **Re anchor bridges**
At every join, insert a one line BBCR bridge that re cites the active snippet.
→ [anchoring-and-bridge-proofs.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/anchoring-and-bridge-proofs.md)
---
## Stitch contract
Minimum fields for any stitched window:
```json
{
"doc_id": "D42",
"section_id": "CH3.2",
"win_idx": 7,
"win_hash": "sha1:6b7f...",
"overlap_tokens": 64,
"prev_id": "D42#CH3.2#6",
"next_id": "D42#CH3.2#8",
"start_token": 14080,
"end_token": 16096
}
````
Rules
* Overlap range must be identical across both windows after normalization.
* Do not allow cross section joins unless the section header is included in the overlap.
* Keep casing and tokenizer identical through the pipeline.
---
## Join planner
**Goal** keep bridges short and anchors stable while covering the whole doc.
1. **Choose window size**: 512 to 1024 tokens, overlap 32 to 96.
2. **Pin anchors**: for each question, tag anchor snippets with `ΔS_to_question`.
3. **Plan path**: sort candidate windows by section, then by `win_idx`.
4. **Assemble**: render windows with header, overlap marker, and re cited anchor.
5. **Verify**: ΔS at each boundary, λ over the stitched answer, coverage against a gold slice.
If ΔS is flat and high across all joins, suspect metric or index mismatch.
→ [retrieval-playbook.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md)
→ [embedding-vs-semantic.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md)
---
## Structural repairs
* **Wrong meaning near a boundary**
→ [embedding-vs-semantic.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md)
* **Order shuffles when windows change**
→ [rerankers.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md) and
→ [patterns/pattern\_vectorstore\_fragmentation.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_vectorstore_fragmentation.md)
* **Entropy spikes after stitching**
→ [entropy-overload.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/entropy-overload.md)
* **Long chain collapses post join**
→ [logic-collapse.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/GlobalFixMap/Reasoning/logic-collapse.md)
---
## Verification
* Sliding window test over the same section keeps citations identical.
* ΔS(join\_left, join\_right) ≤ 0.45 and decreasing with larger overlap.
* λ convergent on two seeds and three paraphrases.
* Coverage across stitched windows ≥ 0.70 for the target section.
* Answer includes a cite then explain block with per join anchors.
---
## Copy paste prompt
```
You have TXT OS and the WFGY Problem Map loaded.
Task: stitch long context with stable joins.
Inputs:
- question: "{q}"
- windows: [{doc_id, section_id, win_idx, win_hash, tokens, text_head, overlap_tokens}]
- candidates: [{snippet_id, section_id, source_url, offsets, ΔS_to_question}]
Do:
1) Compute ΔS for each join. If any ≥ 0.60, propose a re-chunk or overlap increase.
2) Add BBCR micro bridges at every boundary, re citing the active anchor.
3) Apply deterministic reranking with tie break by (doc_id, section_id, win_idx).
4) Return JSON:
{
"joins": [{"from":"...#i","to":"...#i+1","ΔS":0.xx,"action":"ok|rechunk|increase_overlap"}],
"answer": "... cite then explain ...",
"λ_state": "convergent",
"coverage": 0.xx
}
If no valid anchor exists at a join, return the fix page to open for retrieval-traceability.
```
---
## Common gotchas
* **Asymmetric overlap**. Trailing text differs from leading text after normalization.
* **Header drop**. Section headers removed at boundaries, referents disappear.
* **Tokenizer switch**. Ingestion uses one analyzer, reranker another.
* **Duplicate windows**. Same `win_idx` with different hashes compete in top k.
* **Bridge without re citation**. Jumps the boundary without anchor restatement.
---
## When to escalate
* ΔS remains ≥ 0.60 on all joins after overlap increase and reranking
→ rebuild chunks and verify store metric, then retest with a gold slice.
Open: [chunking-checklist.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/chunking-checklist.md), [retrieval-playbook.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md)
* Windows alternate across runs with identical inputs
→ check fragmentation and update skew, then freeze index version.
Open: [patterns/pattern\_vectorstore\_fragmentation.md](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_vectorstore_fragmentation.md)
---
### 🔗 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 | WFGY 2.0 engine is live: full symbolic reasoning architecture and math stack | [View →](https://github.com/onestardao/WFGY/tree/main/core/README.md) |
| Problem Map 1.0 | Initial 16-mode diagnostic and symbolic fix framework | [View →](https://github.com/onestardao/WFGY/tree/main/ProblemMap/README.md) |
| Problem Map 2.0 | RAG-focused failure tree, modular fixes, and pipelines | [View →](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md) |
| Semantic Clinic Index | Expanded failure catalog: prompt injection, memory bugs, logic drift | [View →](https://github.com/onestardao/WFGY/blob/main/ProblemMap/SemanticClinicIndex.md) |
| Semantic Blueprint | Layer-based symbolic reasoning & semantic modulations | [View →](https://github.com/onestardao/WFGY/tree/main/SemanticBlueprint/README.md) |
| Benchmark vs GPT-5 | Stress test GPT-5 with full WFGY reasoning suite | [View →](https://github.com/onestardao/WFGY/tree/main/benchmarks/benchmark-vs-gpt5/README.md) |
| 🧙♂️ Starter Village 🏡 | New here? Lost in symbols? Click here and let the wizard guide you through | [Start →](https://github.com/onestardao/WFGY/blob/main/StarterVillage/README.md) |
---
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> Engineers, hackers, and open source builders who supported WFGY from day one.
> 
⭐ [WFGY Engine 2.0](https://github.com/onestardao/WFGY/blob/main/core/README.md) is already unlocked. ⭐ Star the repo to help others discover it and unlock more on the [Unlock Board](https://github.com/onestardao/WFGY/blob/main/STAR_UNLOCKS.md).
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