RAG Formation · Reference

Failure isolation and graceful degradation

A standalone cheat sheet for learning and testing RAG quality on this site.

$ reference --status
▸ course RAG Formation
▸ mode standalone reference
▸ status Complete
● learn → test → verify

Reference sheet

The guided RAG Formation course content is complete; this reference is available for self-directed practice.

One-line rule

If required evidence is gone, returning a normal-looking answer is an unsafe fallback.

Term	Meaning
Failure isolation	Keeping one dependency’s failure from breaking the whole request or hiding what went wrong.
Graceful degradation	Returning a clearly limited result when it is safe—for example, vector-only search without pretending it has hybrid coverage.
Fail closed	Refusing to answer when a missing dependency means the evidence or authorization cannot be trusted.

Need	Record	Don't claim
Baseline	Command, configuration, observed result	The baseline is a target.
Change	One hypothesis or decision	You can tell what caused the result when several things changed.
Metric	For each dependency, record the symptom, safe fallback, blocked behavior, user message, and metric.	One metric tells you everything about quality.
Safety	A failure and a regression case	A fluent answer proves the system is reliable.

cd demo
python3 setup_demo.py status

Artifact: A dependency failure matrix that separates safe partial service from fail-closed behavior.

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