[Feature Request] Add a structured RAG failure mode checklist (WFGY 16-problem map) for OpenSearch based pipelines

[onestardao]

Is your feature request related to a problem? Please describe

OpenSearch is increasingly used as the vector backend for RAG (Retrieval-Augmented Generation) systems.

When a RAG system produces incorrect, stale, or hallucinated answers, many teams are unsure whether the root cause lies in:

• OpenSearch indexing configuration
• Embedding mismatch or normalization
• Retrieval strategy (k, filters, hybrid search)
• Application layer logic
• Prompt orchestration

As a result, OpenSearch is sometimes blamed for issues that are actually pipeline-level configuration problems.

There is currently no structured, cross-stack diagnostic checklist in the OpenSearch documentation that helps users systematically distinguish:

1. Vector/index configuration problems
2. Retrieval quality problems
3. Application or prompt logic errors
4. Evaluation and logging blind spots

A standardized failure taxonomy would reduce confusion and improve debugging efficiency.

Describe the solution you'd like

I would like to propose adding a structured RAG failure mode checklist based on the open-source WFGY RAG 16 Problem Map (MIT licensed):

https://github.com/onestardao/WFGY
https://github.com/onestardao/WFGY/tree/main/ProblemMap/README.md

Proposal:

1. Add a documentation page such as:
   "Debugging RAG systems built on OpenSearch"

   The page would:

   • Map common RAG failures to 16 well-defined failure categories
   • Clearly distinguish OpenSearch-level misconfiguration from pipeline-level design errors
   • Provide a structured triage flow for diagnosing issues

2. Provide a minimal example notebook that:

   • Builds a simple OpenSearch-based RAG pipeline
   • Intentionally introduces common failure patterns (dimension mismatch, poor chunking, wrong similarity metric, improper filters, etc.)
   • Shows how each failure maps to a specific category
   • Demonstrates corrective configuration changes

This would not introduce new runtime dependencies.
It would be documentation-level guidance to help users debug their systems more systematically.

Related component

Extensions

Describe alternatives you've considered

Currently, most debugging approaches rely on ad-hoc experimentation:

• Changing k values
• Re-indexing
• Switching embedding models
• Tweaking similarity metrics
• Adding logs without a structured classification model

While these can work, they lack a shared vocabulary of failure types.

Other frameworks (e.g., LlamaIndex, RAGFlow, academic surveys) have started referencing structured failure taxonomies.

However, OpenSearch documentation does not yet include a consolidated, vendor-neutral RAG failure checklist.

Additional context

The WFGY 16 Problem Map has already been referenced or integrated in:

• RAGFlow troubleshooting documentation
• LlamaIndex RAG diagnostics sections
• ToolUniverse (Harvard MIMS Lab)
• Rankify (University of Innsbruck)
• Multimodal RAG Survey (QCRI LLM Lab)
• Curated lists such as Awesome LLM Apps

The goal is not to introduce a new framework, but to give OpenSearch users a structured debugging vocabulary to reduce misattribution of RAG failures.

If this direction is of interest, I would be happy to prepare a draft documentation PR aligned with OpenSearch style guidelines.

[andrross]

@navneet1v @arjunkumargiri FYI, can you give this a look?