# LangChain — Guardrails and Fix Patterns Use this when your pipeline is built with **LangChain** (LCEL, Runnable*, Agents, Tools) and you see wrong snippets, unstable reasoning, mixed sources, or silent failures that look fine in logs. **Acceptance targets** - ΔS(question, retrieved) ≤ 0.45 - coverage ≥ 0.70 to the intended section or record - λ stays convergent across 3 paraphrases --- ## Typical breakpoints → exact fixes - Retrieval returns plausible but wrong chunks Fix No.1: **Hallucination & Chunk Drift** → [Hallucination](https://github.com/onestardao/WFGY/blob/main/ProblemMap/hallucination.md) Also review **Retrieval Playbook** → [Retrieval Playbook](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md) - High vector similarity, wrong meaning Fix No.5: **Embedding ≠ Semantic** → [Embedding ≠ Semantic](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md) - Hybrid chains with BM25 or HyDE degrade compared to single retriever Pattern: **Query Parsing Split** → [Query Parsing Split](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_query_parsing_split.md) Apply **Rerankers** for ordering control → [Rerankers](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rerankers.md) - Facts exist in the store but never show up Pattern: **Vectorstore Fragmentation** → [Vectorstore Fragmentation](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_vectorstore_fragmentation.md) - Citations missing or inconsistent across LCEL steps Fix No.8: **Retrieval Traceability** + **Data Contracts** → [Retrieval Traceability](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md) · [Data Contracts](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md) - Long Runnable chains flatten style and drift logically Fix No.3 and No.9: **Context Drift** and **Entropy Collapse** → [Context Drift](https://github.com/onestardao/WFGY/blob/main/ProblemMap/context-drift.md) · [Entropy Collapse](https://github.com/onestardao/WFGY/blob/main/ProblemMap/entropy-collapse.md) - Agent loops, role confusion, memory overwrite Fix No.13: **Multi-Agent Chaos** → [Multi-Agent Problems](https://github.com/onestardao/WFGY/blob/main/ProblemMap/Multi-Agent_Problems.md) · [Role Drift](https://github.com/onestardao/WFGY/blob/main/ProblemMap/multi-agent-chaos/role-drift.md) · [Memory Overwrite](https://github.com/onestardao/WFGY/blob/main/ProblemMap/multi-agent-chaos/memory-overwrite.md) - Model sounds confident but is wrong Fix No.4: **Bluffing / Overconfidence** → [Bluffing](https://github.com/onestardao/WFGY/blob/main/ProblemMap/bluffing.md) - Model merges two sources into one answer Pattern: **Symbolic Constraint Unlock** → [Symbolic Constraint Unlock](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_symbolic_constraint_unlock.md) --- ## Minimal LCEL pattern with WFGY checks ```python # Pseudocode. Show the control points you must keep. from langchain_core.runnables import RunnablePassthrough, RunnableMap def retrieve(q): # k sweep and unified analyzer across dense and sparse return retriever.invoke(q, k=10) def assemble(context, q): # schema-locked: system -> task -> constraints -> citations -> answer return prompt.format(context=context, question=q) def reason(msg): # model call runs after cite-then-explain requirement in the prompt return llm.invoke(msg) def wfgy_checks(q, context, answer): # compute ΔS(question, context) and trace why this snippet # enforce thresholds and fail fast when ΔS ≥ 0.60 or λ divergent return metrics_and_trace(q, context, answer) chain = ( {"q": RunnablePassthrough()} | RunnableMap({"context": lambda x: retrieve(x["q"]), "q": lambda x: x["q"]}) | RunnableMap({"msg": lambda x: assemble(x["context"], x["q"]), "q": lambda x: x["q"], "context": lambda x: x["context"]}) | RunnableMap({"answer": lambda x: reason(x["msg"]), "q": lambda x: x["q"], "context": lambda x: x["context"]}) | (lambda x: wfgy_checks(x["q"], x["context"], x["answer"])) ) ```` **What this enforces** * Retrieval is observable and parameterized. * Prompt is schema locked with cite first. * WFGY check runs after generation and can stop the run when ΔS is high or λ flips. * Traces record snippet to citation mapping for audits. Specs and recipes [RAG Architecture & Recovery](https://github.com/onestardao/WFGY/blob/main/ProblemMap/rag-architecture-and-recovery.md) · [Retrieval Playbook](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md) · [Retrieval Traceability](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-traceability.md) · [Data Contracts](https://github.com/onestardao/WFGY/blob/main/ProblemMap/data-contracts.md) --- ## LangChain-specific gotchas * Mixed embedding functions across write and read paths. Rebuild with explicit metric and normalization. See [Embedding ≠ Semantic](https://github.com/onestardao/WFGY/blob/main/ProblemMap/embedding-vs-semantic.md) * RunnableParallel merges outputs without source fences. Add per-source headers and forbid cross-section reuse. See [Symbolic Constraint Unlock](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_symbolic_constraint_unlock.md) * Memory modules re-assert old facts after a refresh. Stamp `mem_rev` and `mem_hash`. See [Memory Desync](https://github.com/onestardao/WFGY/blob/main/ProblemMap/patterns/pattern_memory_desync.md) * Agents tool-call retry loops. Add BBCR bridge steps and clamp variance with BBAM in the prompt recipe. See [Logic Collapse](https://github.com/onestardao/WFGY/blob/main/ProblemMap/logic-collapse.md) --- ## When to escalate * ΔS remains ≥ 0.60 after chunk and retrieval fixes Work through the playbook and rebuild index parameters. [Retrieval Playbook](https://github.com/onestardao/WFGY/blob/main/ProblemMap/retrieval-playbook.md) * Answers flip between runs or sessions Verify version skew and session state. [Pre-Deploy Collapse](https://github.com/onestardao/WFGY/blob/main/ProblemMap/predeploy-collapse.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) | --- > 👑 **Early Stargazers: [See the Hall of Fame](https://github.com/onestardao/WFGY/tree/main/stargazers)** — GitHub stars ⭐ [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.
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