Knowledge retrieval evaluation framework

Test whether an agent finds the right passage, answers only from it, cites it, abstains when the answer is missing and never shows anyone what they may not see — question sets, metrics, a rubric and starting thresholds.

  • Evaluation kit
  • 7 min read
  • Sep 23, 2026
  • Intermediate
  • Evaluation kit

This kit tests one capability in depth: whether an agent that answers from your organisation's knowledge finds the right passage, answers only from what it found, cites it, says so when the answer is not there, and never shows anyone what they may not see. It extends the knowledge dimension of Evaluation Kit 001 — answers match the approved sources and cite them — into a test a team can run on its own.

The thresholds below are recommended starting points to calibrate per mission. They are not results.

Chapter 01

What the kit contains

PartWhat it gives you
Six measurement layersWhat to score separately, and how
Question set specificationHow to collect, compose and label the questions
Answer rubricFour levels with definitions
Starting thresholdsMust-pass and graded levels to calibrate
Run procedureEight steps, from frozen configuration to signed result
Diagnosis tableFrom symptom to likely cause to fix
Scorecard templateOne table to fill in per run
Chapter 02

Score six layers separately

An end-to-end score cannot tell you whether retrieval failed or the answer did. Score each layer on its own.

A tower of six stacked glass discs, each with a small brass instrument, with one cyan beam passing down through all of them
LayerThe questionMeasure
RetrievalDid the right passage come back, near the top?Recall@k; mean reciprocal rank
GroundingDoes the answer say only what the passages say?Faithfulness: share of claims supported
CitationDoes each citation support the sentence it is attached to?Citation accuracy
CurrencyDoes the answer come from the version in force?Answers from superseded versions (count)
AbstentionWhen the sources do not hold the answer, does the agent say so?Correct abstention; false abstention
AccessDo restricted passages stay out for people without access?Leaks (count)
Figure 1. Six layers of a retrieval evaluation.

Recall@k is the share of answerable questions for which at least one correct ("gold") passage appears in the top k results. Mean reciprocal rank averages one over the rank of the first gold passage, so it rewards putting the right passage first. If you grade passages by degree of relevance, nDCG adds that nuance. Retrieval matters most at the top: usually only the first few passages reach the model, and models use long contexts unevenly, so a gold passage far down the list may as well be missing.

Chapter 03

Build the question set

Take questions from search logs, tickets and the people who will use the agent — not from the documents. Questions written by reading the documents use the documents' words and flatter retrieval.

Glowing paper lanterns drift down from a courtyard window into nets and a funnel feeding a seven-part glass sorting vessel

Each item records: the question in the user's own wording; the asker's role (for access tests); whether it is answerable; the expected answer in a sentence; the gold passages (document, section and version); a must-pass flag; and a category.

CategoryWhat it testsStarting share
TypicalCommon questions in real wording40%
ParaphraseThe same need in different words, plain or jargon15%
Exact termProduct codes, clause numbers, names10%
Multi-passageAnswers that need two sources10%
UnanswerablePlausible questions the sources do not answer10%
Access probeQuestions whose answer is restricted for this asker10%
Currency trapOld and new versions both exist5%
Figure 2. A starting mix of categories — recommended, adjust to your domain.

Aim for at least twenty questions per category, so that a single failure moves a rate by no more than five points. Have two people label the gold passages for a sample, let the content owner settle disagreements, and record the reason. Set aside a held-out portion that is never used to tune anything.

Chapter 04

The answer rubric

LevelDefinition
3 — CorrectAnswers fully; every claim is supported by a cited passage from the version in force
2 — AcceptableCorrect and supported, but incomplete, or a citation points to the right document but not the exact passage
1 — WeakPartly correct, or contains an unsupported claim that would not change what the user does
0 — FailWrong; an unsupported claim that would change what the user does; a superseded version; an answer where it should abstain; or restricted content revealed

Model-graded scoring is practical at volume. Write the rubric as specific yes/no questions ("Is every sentence supported by a cited passage?"), and calibrate the grader against people on a sample before trusting it: model judges have known biases, including favouring longer answers and answers in a particular position. People grade every 0, every disagreement, and a sample of the rest.

Four lanterns on a stone mantel fading from full gold glow to dark, with a Wizard's hand holding a snuffer
Chapter 05

Starting thresholds

Warning — These are recommended starting points, not measured results or industry standards. Set the final thresholds per mission, before the first run, with the reason for each — and never lower one after seeing the results.

MeasureRecommended starting thresholdType
Access leaks0Must-pass
Answers from a superseded version, on currency traps0Must-pass
Rubric score on must-pass questionsNo 0 in any runMust-pass
Recall@5, answerable questions≥ 0.90Graded
Faithfulness (claims supported)≥ 95%Graded
Citation accuracy≥ 95%Graded
Correct abstention, unanswerable questions≥ 90%Graded
False abstention, answerable questions≤ 5%Graded
Rubric mean, all questions≥ 2.5Graded

Calibrate against the current process: give someone who answers these questions today the same questions and the same sources, and score them with the same rubric. Raise thresholds where an error is costly — policy, money, safety — and accept lower ones for low-stakes internal look-ups.

Chapter 06

Running the kit

  1. Freeze the configuration — knowledge snapshot, chunking, index, retrieval settings, model and instructions — and record every version.
  2. Run retrieval alone and score recall and rank.
  3. Run end to end, each question at least three times. For must-pass questions the worst run counts.
  4. Score grounding, citation, currency, abstention and access, and apply the rubric.
  5. Read every failure and classify it with the diagnosis table.
  6. Fix causes, not questions. Never edit a question or a gold label to make it pass, unless the label was wrong — and record why.
  7. Record and sign the result against the configuration it tested.
  8. Re-run after any change to sources, chunking, embeddings, retrieval settings, model or instructions.
Five stations in sequence joined by a cyan path: a sealed casket, a lens bench, an archive engine, three trays and a wax seal
Chapter 07

Diagnosing failures

SymptomLikely causeTry
Low recall on paraphrasesVocabulary mismatchHybrid keyword and vector search; query rewriting
Low recall on exact termsVector search aloneAdd keyword search
Right document, wrong passageChunks split a rule from its conditionsChunk by structure; keep headings with chunks
Good recall, poor faithfulnessThe answer adds outside knowledge; too many passagesA cite-or-abstain contract; fewer, reranked passages
Citations that do not support the sentenceCitations attached after writingCite per sentence, from passage identifiers
Superseded answersOld versions still indexedEffective dates; retire superseded versions
LeaksFiltering after ranking, or in the promptFilter by the asker's identity before retrieval
False abstentionsRetrieval misses, or an over-strict instructionCheck retrieval first
A Wizard crouches beside a brass conduit with an open hatch while a second Wizard holds a lens to a leaking crack
Chapter 08

Checklist

  • Questions come from real users, in their own words.
  • Every category in the mix is represented, with at least twenty questions each.
  • Gold passages name the document, section and version.
  • A held-out set exists and is never tuned against.
  • Retrieval is scored on its own before end-to-end runs.
  • The model grader is calibrated against people on a sample.
  • Access probes and currency traps run in every evaluation.
  • Thresholds are written down before the first run, with reasons.
  • Every 0 is read by a person.
  • Results are stored with the exact configuration tested.
Chapter 09

Worked example

Illustrative example, not a client engagement.

Suppose a company prepares an internal assistant for HR policies. The team collects questions from two years of HR inbox messages, removes personal data, and builds a set of about two hundred, following the starting mix. Access probes ask, as a regular employee, about salary bands that only managers may see.

The first retrieval-only run shows a pattern rather than a number to worry about: paraphrased questions ("can I carry over holiday?") miss the policy titled "annual leave entitlement". Adding keyword search alongside vector search, and the policy's common names as metadata, fixes most of them. End to end, one must-pass question fails in one of three runs: the assistant quotes last year's leave policy. The superseded document was still indexed. It is retired, the full set re-runs clean, and the result is signed with the configuration it tested.

Chapter 10

Scorecard template

MeasureThreshold (set before the run)ResultMust-passEvidenceOwner
Access leaks0YesProbe log
Superseded answers0YesCurrency-trap results
Must-pass rubricNo 0YesGraded answers
Recall@5Retrieval log
FaithfulnessClaim checks
Citation accuracyCitation checks
Correct abstentionUnanswerable results
False abstentionAnswerable results
Rubric meanGraded answers

In the Guild's Evaluation Lab, retrieval accuracy and citation quality are two of the sixteen dimensions on the scorecard Oracle owns.

Build with the Guild

Need this capability inside your business?

The Guild builds what the guides describe.