Use this skill to calibrate graders, derive release gates, and compare evaluation or adaptation methods. Domain skills own what to measure; this skill owns the measurement controls. Training loss is telemetry; held-out behavior determines whether an adaptation improved the system.
Quick Reference
| Task | Read or Run | Outcome |
|---|---|---|
| Build a (question, ideal-answer) set and tune it | references/dataset-construction.md |
Sourcing, ideal-answer authoring, run→compare→tune loop, robustness slice by perturbing memorized cases |
| Compose an eval dataset | references/eval-dataset-design.md |
Task distribution, difficulty, sampling, annotation, versioning, contamination, bias audits, golden vs dynamic sets |
| Stop a judge from rating its own output high | references/llm-judge-bias.md |
Self-preference, position, length, verbosity controls |
| Pick / wire an eval framework | references/framework-integration.md |
inspect-ai, lighteval, Ragas, DeepEval, promptfoo, Braintrust integration snippets + when to use each |
| Choose metrics and a pass threshold defensibly | references/threshold-derivation.md |
Metric set by use case with direction and action-if-fails; derive thresholds from a labeled set; inter-rater agreement; gate design |
| Stop flaky runs reading as regressions | references/flake-and-reproducibility.md |
pass@k vs pass^k, seeds, temperature, quarantine, contamination/leakage, system-benchmark hazards (hardware lottery, thermal/background load, unreported CIs) |
| Decide if "A beats B" is real, size the set | references/eval-statistics.md |
Bootstrap CIs, McNemar, power/MDE sizing, FDR, variance reduction |
| Get maximum from an LLM | references/llm-optimization-technique-map.md |
Technique ladder across prompts, data, RAG/tools, test-time compute, SFT, preference/RFT, PEFT, distillation; measured case where a confidence scorer scored below no scorer |
| Decide whether and how to fine-tune | references/fine-tuning-eval-loop.md |
Prompt/RAG/tool baseline, SFT vs preference/RFT vs PEFT, split hygiene, promotion gates |
| Evaluate on live/production traffic | references/online-production-eval.md |
Offline-online correlation, A/B+guardrails, shadow/canary, drift, regression replay, HITL |
| Turn user behavior into eval and preference data | references/conversational-feedback-signals.md |
Implicit NL signals, action signals, edit→preference pairs, collection timing, feedback biases |
| Evaluate refusals, jailbreaks, harm | references/safety-redteam-eval.md |
Over/under-refusal, ASR per attack family, injection, harm rubrics, robustness |
| Evaluate responsible or multimodal AI | references/responsible-multimodal-evaluation.md |
Intersectional fairness, privacy/memorization/poisoning, oversight/appeals, provenance, grounding, diffusion, multimodal attacks, latency/cost |
| Go beyond one judge | references/advanced-judging.md |
Juries, fine-tuned judges, CoT/probability scoring, calibration (kappa/ECE), agentic reward, human-vs-judge routing |
| Evaluate a retrieval, KB, or memory system | references/retrieval-and-memory-eval.md |
Independent held-out set, slice floors, Wilson CIs, confident-wrong rate, per-stage tests, change-triggered regression gate, state-maintenance acceptance tests, cross-tenant canaries, learned-memory baselines, vendor benchmark claims |
| Measure whether memory skills improve an agent | memory-skills-ablation | Validate paired skills-on/off outcomes, complete safety slices, configuration parity and measured telemetry; export descriptive paired results |
| Measure hallucination | references/hallucination-eval.md |
Taxonomy, claim-level scoring, abstention next to hallucination rate, reference-free triage |
Scope Boundaries (Use These Skills for Depth)
- Domain metrics for retrieval (nDCG/MRR/recall, faithfulness) -> ai-rag
- Agent harness: tool/trace grading, refusal/red-team packs, regression suites, CI status model -> qa-agent-testing
- Coding-agent golden tasks, trace replay, cost ops -> ai-coding-agents-observability-evals
- Running benchmark harnesses on Hub models -> use the
huggingface-skills:plugin (external) - Prompt CI/CD and structured output contracts -> ai-prompt-engineering
- Model selection -> ai-architecture-advisor; serving and quantization -> ai-llm-inference; API cost economics -> ops-cost-optimization
Workflow
- Transform the vague ask into a verifiable goal. "Is it good?" is not gradeable. Ask: which case would fail first if the requirement reverted?
- Build the dataset before the grader. Source real questions, author ideal
answers from the system's allowed context, and plan the run→compare→tune loop
— see
references/dataset-construction.md. No dataset, no eval. - Pick the cheapest grader that works. Deterministic check > LLM judge > human. Reserve the LLM judge for what code cannot decide (Rule 5: use the model only for judgment calls).
- If using an LLM judge, control its bias before trusting any number — see
references/llm-judge-bias.md. Judge bias can confound quality with surface features. When one judge isn't enough (high stakes, weak agreement, open-ended), escalate to juries / fine-tuned judges / calibrated scoring — seereferences/advanced-judging.md. - Control flake and leakage with repeated trials (pass^k for reliability
gates, pass@k only for capability), low judge temperature, seed
pinning, and held-out testsets — see
references/flake-and-reproducibility.md. - Derive thresholds from a labeled calibration set, not intuition or copied
targets — see
references/threshold-derivation.md. Size the gating set and judge "A beats B" with statistics (bootstrap CIs, McNemar, power/MDE, FDR) — seereferences/eval-statistics.md. For frozen paired results, runpython3 scripts/analyze_paired_results.py results.csv --estimand unit_mean; declare whether units or clusters define the target population first. A population-level superiority claim needs design-compatible uncertainty; exact fixed-suite differences remain descriptive evidence. - Only fine-tune after the baseline has earned it. Compare prompt/RAG/tool
fixes first, then choose SFT for imitation/style/format/tool-call behavior,
preference/RFT for rubric-scored reasoning or tradeoffs, and PEFT/LoRA/QLoRA
when adapting an open model under compute or deployment constraints — see
references/fine-tuning-eval-loop.md. Training loss is telemetry; held-out behavior is the verdict. - Apply the full optimization ladder, not one pet method. For maximum LLM
performance, evaluate cheap prompt/context/tool fixes, then inference-time
methods (self-consistency, best-of-N, rerank/verify/refine), then data/SFT,
preference/RFT/RLVR, PEFT, and distillation as the evidence warrants — see
references/llm-optimization-technique-map.md. Each technique gets its own failure mode and gate. - Gate loudly. A gate that passes while silently skipping cases is a failure dressed as success (Rule 12: fail loud). Report skipped/quarantined cases in the gate output.
- Extend past the offline gate where the system warrants it. Add
safety/red-team evaluation (refusal precision/recall, jailbreak ASR,
injection, harm rubrics) — see
references/safety-redteam-eval.md— and, once in production, online evaluation (offline-online correlation, A/B with guardrails, drift, regression replay) — seereferences/online-production-eval.md. The offline gate is a filter; production is the verdict.
Core Principles
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The judge is a model with failure modes. Treat its scores as one calibrated input, never as ground truth.
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Judge independence needs evidence. Prefer a different judge model and calibrate against human labels and planted failures. A different family reduces one self-preference risk; it does not establish an unbiased grader.
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Behavior, not plausibility. Rubrics that reward "looks good" reward length and confidence. Pin rubrics to verifiable behavior.
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No threshold without a labeled set. A copied target (">95%") is a guess until validated on your own distribution.
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No fine-tune without a baseline and a holdout. A tuned model that beats no prompt/RAG/tool baseline, or only wins on the training/dev set, has not earned release.
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No "maximum performance" without a technique ladder. The best result often comes from composition: cleaner data + stronger retrieval/tool contracts + calibrated judge + small test-time search + selective post-training. Test the cheapest credible lift before moving weights.
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Optimize behavior, not hidden knowledge. Fine-tune for stable formatting, domain style, tool-use patterns, rubric-following, or compact specialized behavior. Use retrieval/context for facts that change or must be cited.
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Locate variability before changing the gate. Regrade frozen outputs to separate judge instability from system unreliability; keep real stochastic failures in the reliability denominator.
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Held-out or it's contaminated. If tuning ever saw the eval cases, the scores are inflated.
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Check that the proxy still tracks the outcome. Tuning to a metric can weaken its relationship with user outcomes. Re-anchor it against fresh human labels or production evidence when the model, grader, or traffic changes.
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Match uncertainty to the claim. Population-level pass rates, win rates, and judge-human agreement need design-compatible uncertainty. Exact counts over a fixed deterministic suite describe that suite and need their denominator and limits; do not invent sampling intervals for them. See
references/eval-statistics.md. -
Eval framework APIs (inspect-ai, lighteval, Ragas, DeepEval, promptfoo, Braintrust) change across releases. Verify current API and version against official docs before recommending a specific call or flag.
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Optimization-method papers from arXiv are often preprint-only and benchmark-sensitive. Treat unreplicated methods as
validate, notpromote, until they beat a strong local baseline with cost/latency/safety gates. -
Judge-bias findings (position, length, self-preference) are well-replicated, but their magnitudes (and for length, the direction) are judge- and prompt-dependent — re-measure on your own setup; do not quote a fixed number as universal.
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Fine-tuned-judge models (Prometheus, JudgeLM, and successors) and jailbreak attack/defense results move fast — verify the current model, license, and benchmark-agreement claims before recommending a specific judge or asserting a model is robust to a given attack family.
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Indirect prompt injection is a leading agentic attack class; treat any "the agent is safe against injection" claim as requiring fresh adaptive testing.
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Statistics methods (bootstrap, McNemar, FDR, power/MDE) are stable, but verify the exact API (scipy/statsmodels) before copying a call.
Release Decision Gate
Select foundations only when they change the eval decision
- If a proxy score is being interpreted as quality, trust, fairness, or another construct, or compared across populations or grader versions, use measurement theory. Return the construct, observed proxy, interpretation evidence, comparability limits, and missing validation. Skip this audit for a routine execution of an already documented instrument with unchanged interpretation and population.
- If uncertainty, dependent repeats/clusters, multiple comparisons, or repeated stopping can change a conclusion, use statistical inference. Return the estimand, independent unit, interval method and assumptions, and the multiplicity/stopping rule. Skip inference for reporting exact outcomes of a fixed deterministic fixture suite without a population claim; report its denominator and scope instead. Neither foundation substitutes for this skill's dataset, grader controls, or release decision.
Write the release rule before scoring: required tasks and slices, minimum acceptable effect, uncertainty method, regression budget, and handling for grader errors or missing results. A candidate passes only when every blocking slice is present and the predeclared decision rule clears. Learned, model, heuristic, and human graders must pass planted-good and planted-bad controls that detect calibration drift; deterministic exact-match, schema, executable-test, and invariant graders instead need versioned implementations with relevant positive and negative fixtures. Missing denominators, stale fingerprints, failed grader controls, or an unavailable judge produce inconclusive, never an implicit pass. For memory-skill effectiveness, use the paired ablation procedure; public development fixtures validate the harness, while an independently frozen set is required for a held-out claim. Keep measured results separate from the release recommendation.
Known Traps
- Grading an agent with the same model that produced the output (self-preference)
- Comparing two candidates in fixed order and trusting the winner (position bias)
- Copying a
>95%threshold from a blog without validating it on your data - One judge call per request with no cheap deterministic pre-filter (cost blowup)
- Quarantining genuine stochastic system failures until the gate becomes green
- Generating a synthetic testset from the same docs used to tune the system
- Reporting a builder-written eval as held-out for a retrieval/KB/memory system, or
letting the eval fall back silently when the index is stale (see
references/retrieval-and-memory-eval.md) - Reporting "all passed" when some cases were skipped or errored (silent success)
- Claiming "A beats B" from a point estimate with no confidence interval or test
- Gating a small regression on a set far too small to detect it (no power check)
- Tuning safety to block harm without a benign set, so the model over-refuses
- Trusting a seed for reproducibility through a hosted API that isn't deterministic
- Fine-tuning because the prompt is messy, the retrieval is broken, or the tool contract is ambiguous
- Declaring the fine-tune better from training loss, validation loss, or one cherry-picked demo instead of a paired held-out eval with CIs
- Letting the training set, grader calibration set, and release gate share cases
- Training a judge or reward model on labels produced only by the same model family it will later grade
Navigation
Resources:
- references/dataset-construction.md - Sourcing questions, authoring ideal answers, run→compare→tune loop
- references/eval-dataset-design.md - Dataset composition: distribution, difficulty, sampling, annotation, versioning, contamination, bias, golden vs dynamic
- references/llm-judge-bias.md - Judge bias taxonomy and controls
- references/framework-integration.md - Framework selection and integration snippets
- references/threshold-derivation.md - Metric set by use case, deriving thresholds and gates from labeled data
- references/flake-and-reproducibility.md - Flake, seeds, contamination, leakage, system-benchmark hazards
- references/eval-statistics.md - Paired cluster bootstrap workflow and analyzer, McNemar, power/MDE, FDR, variance reduction
- references/llm-optimization-technique-map.md - Maximum-performance technique ladder and eval gates
- references/fine-tuning-eval-loop.md - Eval-first fine-tuning decisions, SFT/preference/RFT/PEFT selection, split hygiene, promotion gates
- references/online-production-eval.md - Offline-online correlation, A/B+guardrails, drift, replay, HITL
- references/conversational-feedback-signals.md - Implicit/action user-feedback taxonomy, edit→preference pairs, collection timing, feedback biases
- references/safety-redteam-eval.md - Refusal precision/recall, jailbreak/injection, harm rubrics, robustness
- references/advanced-judging.md - Juries, fine-tuned judges, scoring methods, calibration, human-vs-judge routing, agentic reward
- references/retrieval-and-memory-eval.md - Independent held-out sets, slice floors, per-stage pipeline tests, change-triggered regression gate, exact-state scoring
- references/hallucination-eval.md - Hallucination taxonomy, claim-level metrics, abstention, judge prompt, reference-free triage
- references/responsible-multimodal-evaluation.md - Responsible-AI measurement and multimodal grounding, diffusion, safety/red-team, latency, and cost gates
- scripts/prompt_eval_runner.py - Offline regression check of pre-collected outputs in a JSONL suite against
expected_substringsand/orexpected_schema. A record with no assertions fails; malformed assertion fields, non-JSON numeric constants, and duplicate case IDs exit 2. It calls no model API and measures nothing statistical; compare two variants withscripts/analyze_paired_results.py. - data/sources.json - Sources to verify against
Related skills:
Learnings Loop
Consult learnings.consolidated.md for relevant prior decisions or pitfalls;
open learnings.md only when their history is needed. Skip both when unrelated
to the task. After applying it, append one dated bullet to
learnings.md via agents-skills-feedback-loop/scripts/append_learning.py if you
hit a pattern, mistake, or surprising fact. Do not modify SKILL.md itself.