Model

Claude Opus 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYZ5HHYWNP37Q070D9HKEWT

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 grandfather clock struck midnight precisely as Detective Sarah Chen stepped into the dimly lit Victorian mansion's foyer. Rain hammered against the tall windows while thunder rumbled ominously in the distance, shaking the ancient wooden floorboards beneath her. A butler with hollow eyes and pale skin gestured silently toward the grand staircase leading up to the crime scene. The victim lay sprawled across an expensive Persian rug, a jeweled letter opener protruding grotesquely from his chest, blood pooling everywhere. Lord Ashworth had been wealthy, powerful, and despised by nearly everyone who had ever crossed paths with him in life. His widow stood motionless by the fireplace, her black dress perfectly pressed, her expression revealing absolutely nothing about her inner thoughts. Three guests had been staying at the estate that fateful weekend, and each one possessed compelling reasons to want him dead. Detective Chen pulled out her worn leather notebook, knowing that somewhere among these privileged suspects lurked a calculating and ruthless killer.
created_at"2026-02-08T15:50:53.845123+00:00" Sunday, February 8th, 2026 at 3:50:53 PM GMT+00:00
model"anthropic/claude-4.5-opus-20251124" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1687
moderation_latency178
generation_time6528
tokens_prompt35
tokens_completion198
native_tokens_prompt44
native_tokens_completion223
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" 
usage0.005795
router(null)
provider_responses
0
id"cbfebfd5-5e74-45ab-ab92-72adc1265e3c" 
status200
is_byokfalse
latency1686
endpoint_id"de32581c-2e11-4f54-8d29-e8a6e19d3038" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-opus-20251124" 
api_type"completions" 
id"gen-1770565846-EEFmoIV6BIlgg0gmgNGw" 
upstream_id"cbfebfd5-5e74-45ab-ab92-72adc1265e3c" 
total_cost0.005795
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
75.4082% Matches word count n/a
neededCleanfalse
sentences8
wordCounts
019
120
220
321
420
521
621
721