Model

Claude Opus 4.6

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYX7SK0PX8HEX3N8Q55KBJS

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 mansion stood silently at the end of Blackwood Lane, its windows dark like the eyes of a skull. Detective Sarah Chen arrived at precisely eleven fifteen that evening, her boots crunching against the gravel of the long winding driveway ahead. A single light flickered behind the curtain on the second floor, casting strange and eerie shadows that danced across the lawn. The front door hung open just a few inches, revealing nothing but an impenetrable darkness that seemed almost alive and breathing. She pushed it wider with her gloved hand, and the smell of copper and roses hit her like a freight train. On the marble floor of the grand foyer lay the body of billionaire Marcus Webb, his silk robe soaked completely in blood. His eyes were open wide, frozen in an expression of pure terror, as though he had seen something truly beyond comprehension. A shattered crystal glass rested near his outstretched fingers, and deep red wine had pooled and mixed with the thickening blood. Sarah knelt beside the body and noticed something unusual clutched tightly in his other hand, a small torn piece of paper. Written on it in his own trembling handwriting were just three words that would change the entire course of this investigation.
created_at"2026-02-08T15:17:10.565855+00:00" Sunday, February 8th, 2026 at 3:17:10 PM GMT+00:00
model"anthropic/claude-4.6-opus-20260205" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1132
moderation_latency144
generation_time6941
tokens_prompt35
tokens_completion243
native_tokens_prompt44
native_tokens_completion268
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" 
usage0.00692
router(null)
provider_responses
0
id"c96d2b51-11f8-4d4f-8ed5-e236665b75e9" 
status200
is_byokfalse
latency1132
endpoint_id"a8708fb9-08ea-43bb-a3b1-165c87ef09df" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.6-opus-20260205" 
api_type"completions" 
id"gen-1770563823-BOot2PumgifJmBQOwMyQ" 
upstream_id"c96d2b51-11f8-4d4f-8ed5-e236665b75e9" 
total_cost0.00692
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
55.1639% Matches word count n/a
neededCleanfalse
sentences10
wordCounts
020
122
221
321
421
522
621
721
821
921