Model

Claude Sonnet 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYWZ11HN0J4XXS4DTW16G53

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 body lay sprawled across the marble floor, one pale hand still clutching the stem of a crystal champagne glass. Detective Sarah Chen knelt beside the victim, noting the purple bruising around the neck and the scattered pearls from her necklace. Outside the ballroom windows, thunder rumbled ominously while rain streaked down the glass panes like tears for the newly deceased woman. The guests huddled in small groups, their elegant evening wear now seeming absurd given the grim circumstances of this unexpected tragedy. Sarah stood slowly, her keen eyes scanning the room for anything out of place, any clue to explain this murder tonight. A waiter nervously approached, wringing his white-gloved hands, clearly desperate to share what he had witnessed during the fatal evening's events. "She argued with someone before midnight," he whispered urgently, glancing around to ensure none of the other party guests overheard him. Sarah pulled out her notebook, pen poised and ready, knowing that the next few hours would determine whether justice prevailed here. The mansion's grandfather clock began to chime, its deep tones marking one o'clock, the witching hour when secrets began unraveling slowly.
created_at"2026-02-08T15:12:24.272046+00:00" Sunday, February 8th, 2026 at 3:12:24 PM GMT+00:00
model"anthropic/claude-4.5-sonnet-20250929" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1889
moderation_latency149
generation_time7739
tokens_prompt35
tokens_completion234
native_tokens_prompt44
native_tokens_completion265
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" 
usage0.004107
router(null)
provider_responses
0
id"c75766ae-64d7-48c9-9606-d5aa9bda895b" 
status200
is_byokfalse
latency1889
endpoint_id"d8bee848-f020-454a-b2be-4a7ce868f99f" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-sonnet-20250929" 
api_type"completions" 
id"gen-1770563535-MIT9WTyCbN7MKRLqKaBV" 
upstream_id"c75766ae-64d7-48c9-9606-d5aa9bda895b" 
total_cost0.004107
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
59.7894% Matches word count n/a
neededCleanfalse
sentences9
wordCounts
020
121
221
321
421
522
621
721
821