Agentic Evaluation Framework Skill for Claude

Agentic Evaluation Framework

> Category: Engineering

> Domain: AI Engineering

Overview

Design and run trustworthy evaluations for LLM and agent outputs: pick the right grading method (programmatic check, LLM-as-judge, or human review), write a scoring rubric that judges can apply consistently, rank competing variants by pairwise comparison, and watch for the biases that quietly corrupt judge scores — position bias, verbosity bias, and self-preference. The goal is an eval that you can *trust enough to ship on*: calibrated against human labels, cheap enough to run on every change, and tracked alongside cost and latency so you never trade quality away by accident. This skill is model- and vendor-agnostic: it reasons about the evaluation *method*, not any one provider's API, and its scripts aggregate scores you have already collected — they never call a model.

Clarify First

Before designing or running an evaluation, confirm these inputs. If any is unknown or vague, ASK — do not assume:

• [ ] What "good" means — the dimensions you care about (accuracy, helpfulness, safety, format, tool-use) and their relative weight (defines the rubric criteria and weights)
• [ ] Grading method — can a deterministic check decide it, do you need an LLM judge, or must a human review it? (selects programmatic vs rubric_scorer.py absolute scoring vs pairwise_ranking.py comparison vs human-in-the-loop)
• [ ] Ground truth & budget — do you have human-labeled examples to calibrate the judge against, and what cost/latency per eval run is acceptable? (sets calibration plan and the quality/cost/latency budget)

Stop rule: ask only the 2-3 that most change the output. If the user says "just draft it," proceed and list your assumptions.

Quick Start

cd engineering/agentic-evaluation-framework

# 1. Score outputs against a weighted rubric + check inter-rater agreement
python scripts/rubric_scorer.py --data rubric_scores.json

# 2. Rank competing variants from pairwise (A-vs-B) judgements
python scripts/pairwise_ranking.py --data pairwise_matches.json

# JSON output for piping into a dashboard or CI gate
python scripts/rubric_scorer.py --data rubric_scores.json --json

Tools Overview

| Tool | Purpose | Key Flags |

|------|---------|-----------|

| scripts/rubric_scorer.py | Aggregate per-criterion scores into weighted totals, per-criterion means, pass/fail vs thresholds, and an inter-rater agreement metric | --data, --json |

| scripts/pairwise_ranking.py | Turn head-to-head win/loss records into a ranking via Elo + Bradley-Terry, plus a win-rate matrix | --data, --k, --base, --json |

Both scripts: Python 3 standard library only, argparse CLI, --json and human-readable output. They compute over scores you provide and never call a model. Run --help for full usage.

Workflows

1. Build and calibrate an absolute-scoring rubric

• Translate "what good means" into 3-6 named criteria, each with a weight, a 1-5 (or 1-7) scale, and a written anchor for every scale point (see references/llm-judge-methodology.md).
• Have at least two graders — human, or human plus model — independently score a calibration set, and record the per-criterion scores as the rubric_scorer.py input JSON.
• Run rubric_scorer.py and read inter_rater_agreement: low agreement means the rubric is ambiguous, not that a grader is wrong — tighten the anchors and re-score before trusting any number.
• Once graders agree, treat the human scores as ground truth and check that the LLM judge's scores correlate; if not, revise the judge prompt or fall back to human review for that criterion.
• Wire the passing rubric into CI as a gate (--json → pass/fail), and re-run agreement periodically to catch judge drift.

2. Rank model/prompt variants by pairwise comparison

• When absolute scores are noisy, switch to pairwise: show the judge two outputs (A and B) for the same input and ask only "which is better?" — easier and more reliable than an absolute number.
• Mitigate position bias by running each pair in both orders (A,B and B,A) and counting a win only if it survives both; record outcomes as pairwise_ranking.py matches, using "winner": "tie" for disagreements.
• Run pairwise_ranking.py to get Elo and Bradley-Terry rankings plus the win-rate matrix; Bradley-Terry is order-independent and preferred for a fixed batch, Elo for a streaming sequence of matches.
• Inspect the win-rate matrix for intransitivity (A>B, B>C, but C>A) — a sign of an unreliable judge or genuinely tied variants; collect more matches or add human adjudication.
• Report the ranking next to cost and latency per variant so the "winner" is the best *quality-per-dollar-per-second*, not just the highest score.

Reference Documentation

• references/llm-judge-methodology.md — rubric design and scale anchoring; absolute vs pairwise scoring; the judge-bias catalog (position, verbosity, self-preference, sycophancy) with concrete mitigations; calibrating a judge against human labels; the eval feedback loop (collect → grade → analyze → fix → regression-gate); and the quality/cost/latency metrics to track together.
• references/eval-pitfalls.md — the anti-patterns that make evals lie: single-grader rubrics, judging on the training set, gameable metrics, ignoring variance, optimizing the judge instead of the model, and the decision table for when to use a programmatic check vs an LLM judge vs human review.

Common Patterns

• Cheapest valid grader wins — if a deterministic check (regex, JSON-schema, unit test, exact match) can decide it, use that; reach for an LLM judge only for fuzzy quality, and human review only for high-stakes or judge-calibration work.
• Pairwise over absolute when scores are noisy — "which is better, A or B?" is more reliable than "rate this 1-5"; use absolute rubrics for thresholds/gates and pairwise for model selection.
• Swap positions to kill position bias — always run each comparison in both orders and only count wins that survive both; a variant that only wins in position A is a judge artifact.
• Length is not quality — strip or normalize for verbosity bias; a longer answer is not a better one, and judges systematically over-reward length unless you control for it.
• Don't let a model grade its own homework — self-preference bias means a model favors its own outputs; use a different judge family from the model under test, or anchor on human labels.
• Calibrate before you trust — a judge is only as good as its agreement with humans on a held-out set; measure that agreement first, then automate.
• Track quality, cost, and latency as one number — a quality win that triples cost or latency may be a net loss; always report the three together so the tradeoff is explicit.
• Evals are regression tests for prompts — freeze a labeled eval set, gate every prompt/model change on it, and grow the set from production failures you find.