Model

Claude Sonnet 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGZ05SJ74ZJ7JKMYPXYSSPYJ

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 Velvet Room The grand chandelier cast dancing shadows across the marble floor as thunder rolled through the dark September night outside. Detective Sarah Chen stepped over the velvet rope, her practiced eyes already cataloging every detail of the opulent crime scene. The victim lay sprawled beside the mahogany desk, still wearing his tuxedo, a dark stain spreading across the pristine carpet. "Harrison Blackwood, age fifty-two, found by his wife at approximately ten fifteen," Officer Martinez recited from his small leather notebook. Sarah knelt beside the body, noting the peculiar angle of the head and the faint scent of almonds lingering. The study's French doors stood open despite the storm, rain soaking the Persian rug and puddling near the victim's outstretched hand. A crystal glass lay shattered nearby, its contents mixing with rainwater, creating small rivers that wound toward the antique bookshelf. "Where is Mrs. Blackwood now?" Sarah asked, standing slowly, her knees protesting after the long day of previous investigations and meetings. "Upstairs in the master bedroom with the family physician. She was quite hysterical when we arrived," Martinez replied, glancing nervously. Sarah walked to the open doors, observing muddy footprints that led from outside, crossed the study, then disappeared into the hallway. The mansion held twenty rooms, fifteen potential suspects attending tonight's charity gala, and one dead billionaire who knew too many secrets.
created_at"2026-02-08T16:08:31.827154+00:00" Sunday, February 8th, 2026 at 4:08:31 PM GMT+00:00
model"anthropic/claude-4.5-sonnet-20250929" 
app_id182717
external_user(null)
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cancelledfalse
latency1359
moderation_latency196
generation_time7307
tokens_prompt35
tokens_completion285
native_tokens_prompt44
native_tokens_completion332
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" 
usage0.005112
router(null)
provider_responses
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id"b1f5e178-7264-431a-aebd-0b3dd8060bed" 
status200
is_byokfalse
latency1357
endpoint_id"d8bee848-f020-454a-b2be-4a7ce868f99f" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-sonnet-20250929" 
api_type"completions" 
id"gen-1770566903-rAxuVGJBxqhifch4Eww3" 
upstream_id"b1f5e178-7264-431a-aebd-0b3dd8060bed" 
total_cost0.005112
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
68.7143% Matches word count n/a
neededCleanfalse
sentences12
wordCounts
04
119
220
320
421
519
621
720
821
920
1021
1121