Model

Claude Haiku 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYYQVF8FYEMPHKPBWF3P3G3

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 in the Library The rain fell heavily on the cobblestone streets of Victorian London, casting dark shadows everywhere. Inspector Ashford arrived at the grand mansion just as the church bells struck midnight. Lady Pemberton's body lay motionless across the mahogany desk in the dusty old library. Her silk evening gown was stained with blood; a pearl-handled revolver rested near her hand. The butler stood nervously in the doorway, wringing his hands and avoiding the inspector's piercing gaze. "Who discovered the body, and when exactly did you find the poor woman?" Ashford demanded. The servant's voice trembled as he explained that he heard the gunshot around eleven o'clock. Three other people were in the mansion that night, all of them with secrets to hide. The inspector surveyed the room carefully, noting a broken window and muddy footprints on the floor. This case would prove far more complicated than anyone had initially anticipated or wanted to believe.
created_at"2026-02-08T15:43:21.9894+00:00" Sunday, February 8th, 2026 at 3:43:21 PM GMT+00:00
model"anthropic/claude-4.5-haiku-20251001" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency661
moderation_latency(null)
generation_time3253
tokens_prompt35
tokens_completion197
native_tokens_prompt44
native_tokens_completion215
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" 
usage0.001119
router(null)
provider_responses
0
id"msg_01EZjtX6yBx67Jv5eebud9Vz" 
status200
is_byokfalse
latency661
endpoint_id"41d2915a-92e6-4993-b537-210b4e10cba8" 
provider_name"Anthropic" 
model_permaslug"anthropic/claude-4.5-haiku-20251001" 
api_type"completions" 
id"gen-1770565398-dhwlQlZExD4oXmv5LozI" 
upstream_id"msg_01EZjtX6yBx67Jv5eebud9Vz" 
total_cost0.001119
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic" 

Evaluation details

Result Evaluator Details Meta Data
0.0154% Matches word count n/a
neededCleanfalse
sentences11
wordCounts
06
115
214
314
416
516
615
715
816
916
1016