Model

Claude Sonnet 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYY8RT2B493E2W2H5ZSPA2T

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 Venetian Mask The body lay sprawled beneath the crystal chandelier, a crimson pool spreading slowly across the polished white marble floor of the grand ballroom. Detective Sarah Chen stepped carefully around the blood, her keen eyes absorbing every detail of the macabre scene before her that cold morning. The victim wore an elaborate Venetian mask, gold and emerald feathers still perfectly arranged despite the violent struggle that had clearly preceded death. "Time of death approximately midnight," the medical examiner announced, kneeling beside the corpse with gloved hands examining the fatal wound carefully now. Lady Catherine Ashworth stood frozen by the doorway, her silk gown rustling slightly as she trembled, unable to look away from her deceased guest. "The mask ball ended at eleven," she whispered hoarsely, her voice breaking with emotion as she clutched the doorframe for support and stability. Detective Chen turned toward her, notebook ready, and asked the question that would begin unraveling the twisted truth hidden behind elegant masks tonight. "Who left the ballroom between eleven and midnight, and more importantly, Lady Ashworth, who had reason to want Lord Blackwood dead?" she demanded firmly.
created_at"2026-02-08T15:35:11.116352+00:00" Sunday, February 8th, 2026 at 3:35:11 PM GMT+00:00
model"anthropic/claude-4.5-sonnet-20250929" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1311
moderation_latency222
generation_time6601
tokens_prompt35
tokens_completion232
native_tokens_prompt44
native_tokens_completion264
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" 
usage0.004092
router(null)
provider_responses
0
id"2397cff6-e93b-4191-9e2e-5217d3ade8da" 
status200
is_byokfalse
latency1311
endpoint_id"d8bee848-f020-454a-b2be-4a7ce868f99f" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-sonnet-20250929" 
api_type"completions" 
id"gen-1770564903-GsxJnJt19fJJNfdbHqYW" 
upstream_id"2397cff6-e93b-4191-9e2e-5217d3ade8da" 
total_cost0.004092
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
2.1283% Matches word count n/a
neededCleanfalse
sentences9
wordCounts
04
123
223
323
422
524
623
723
824