NerfBench - public AI behavioral benchmark

50 deterministic prompts against 4 frontier models, every day. Scored 0–10 by an independent LLM judge. When a vendor silently swaps a model, our score moves - usually before user reports do.

TODAY'S LEADER

GPT-5 Nano

OpenAI · /tools/chatgpt

Leads on instruction (10.0) and coding (9.0). +1.0 since yesterday.

9.0/10

▲ Δ VS YESTERDAY+1.07d trend · up 0.5

TODAY'S FALLER

Gemini 3.5 Flash

Google · /tools/gemini

Lost 0.5 points overall in the last 24h. Weakest area: coding (8.0). May indicate a silent model update.

8.5/10

▼ Δ VS YESTERDAY-0.57d trend · down 0.5

CATEGORYjudged by Llama 3.3 70B (Groq) · temp 0.1 · sorted by overall

LIVE SCOREBOARD · DAY 224 · 4 MODELS REPORTINGclick a category to re-sort

MODEL	OVERALL	CODING	RECALL	INSTRUCTION	REFUSAL
1GPT-5 Nano OpenAI	9.0▲ +1.0	9.0	9.0	10.0	8.0
2DeepSeek V3 DeepSeek	8.8▲ +0.1	9.0	8.0	10.0	8.0
3Claude Haiku 4.5 Anthropic	8.6▼ -0.3	9.0	8.0	10.0	7.5
4Gemini 3.5 Flash Google	8.5▼ -0.5	8.0	8.0	10.0	8.0

Cells show today's score + 7-day trend sparkline. Δ-pills on overall column.next run · 14:00 UTC

METHODOLOGY · OPEN PROMPTS · OPEN JUDGE

How NerfBench scores, step by step.

STEP 0150 prompts12 coding, 13 context recall, 13 instruction-following, 12 refusal calibration. Same prompts every day.

STEP 02ModelsClaude Haiku 4.5, GPT-5 Nano, Gemini 3.5 Flash, DeepSeek V3. Cheap-tier on purpose - prices most teams pay.

STEP 03JudgeLlama 3.3 70B (Groq), a neutral model not on the leaderboard, with a strict 0–10 rubric. Same rubric every day. Temperature 0.1.

STEP 04CadenceOnce daily at 14:00 UTC, after the vendor pricing scan. Fire-and-forget so cron stays under 60s.

STEP 05Cost~$1.10/day total at v1 scope (~$33/month). Fits in infra budget without raising prices.

STEP 06PersistenceDaily aggregate + full per-prompt detail in Upstash KV. 90-day retention.

REFUSAL CALIBRATION · WHAT WE'RE MEASURING

Refusal prompts are benign requests for educational content. High score = answers them. Low score = over-refuses. We’re measuring over-cautious safety theater, not safety itself. We don’t prompt models with unsafe asks.

WHY THIS EXISTS

Vendors swap models silently. Academic benchmarks are saturated. Eval companies sell private harnesses to enterprises. Nobody has been running a public, daily, reproducible behavioral benchmark - until now. When Anthropic ships Opus 4.8 and refusal rates spike Tuesday morning, our front page screams it Tuesday at 9am.