Model

Claude Opus 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYYKV6W44CHG92RVYPGW5TG

Model input

User/Human
Please write the opening scene of a murder mystery where each sentence has exactly 20 words. Please make sure that each sentence has the same length. Only return the opening itself.

Model response

AI
The old Victorian mansion stood silent against the stormy night sky, its windows dark except for one flickering light. Detective Sarah Chen stepped out of her car, rain pelting her face as she approached the imposing iron gates ahead. A uniformed officer waited nervously on the porch, his flashlight beam cutting through the heavy sheets of falling water outside. She had received the call at midnight, interrupting her first peaceful sleep in nearly three weeks of exhausting investigative work. The victim was wealthy industrialist Marcus Webb, found dead in his private study by his terrified young housekeeper this evening. No signs of forced entry existed anywhere in the house, which meant the killer likely knew the victim quite well indeed. Sarah pulled on latex gloves as she crossed the threshold, noting the expensive art pieces lining every wall of hallway. The body lay crumpled beside an ornate mahogany desk, a crystal whiskey glass shattered into tiny pieces on the floor. Blood pooled beneath his head from a wound that suggested someone had struck him with tremendous force from behind tonight. His eyes remained open, frozen in an expression of complete surprise, as though death had come from a trusted friend nearby.
created_at"2026-02-08T15:41:14.592401+00:00" Sunday, February 8th, 2026 at 3:41:14 PM GMT+00:00
model"anthropic/claude-4.5-opus-20251124" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency2545
moderation_latency167
generation_time7304
tokens_prompt35
tokens_completion232
native_tokens_prompt44
native_tokens_completion250
native_tokens_completion_images(null)
native_tokens_reasoning0
native_tokens_cached0
num_media_prompt(null)
num_input_audio_prompt(null)
num_media_completion0
num_search_results(null)
origin"https://ncbench.com/" 
is_byokfalse
finish_reason"stop" 
native_finish_reason"stop" 
usage0.00647
router(null)
provider_responses
0
id"8cb4d656-ee23-4baf-8a2c-1af0cdc3bb92" 
status200
is_byokfalse
latency2545
endpoint_id"de32581c-2e11-4f54-8d29-e8a6e19d3038" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-opus-20251124" 
api_type"completions" 
id"gen-1770565266-1HCuzEY6kH7wMKlh7kGs" 
upstream_id"8cb4d656-ee23-4baf-8a2c-1af0cdc3bb92" 
total_cost0.00647
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
88.1959% Matches word count n/a
neededCleanfalse
sentences10
wordCounts
019
120
220
320
420
521
620
720
820
921