Model

Claude Sonnet 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYZXK5NCAVDSSK9X3A03RJV

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 rain hammered against the library windows as Detective Sarah Chen studied the body sprawled across the Persian rug below. Lord Ashworth lay face down, a silver letter opener protruding from between his shoulder blades, blood pooling beneath him. The grandfather clock in the corner struck midnight, its chimes echoing through the room where death had visited tonight. Six dinner guests stood frozen in the doorway, their faces pale with shock, each one a potential suspect now. Sarah pulled on her latex gloves and knelt beside the victim, noting the expensive cologne still lingering in the air. "Nobody leaves this manor," she announced firmly, her voice cutting through the tension like the blade that killed him. The butler wrung his hands nervously, his starched collar now askew, sweat beading on his forehead despite the cold. Outside, lightning illuminated the estate grounds, revealing no escape routes through the storm that trapped them all here together. Sarah knew that somewhere among these frightened faces hid a killer, and she had until dawn to find them.
created_at"2026-02-08T16:04:02.789641+00:00" Sunday, February 8th, 2026 at 4:04:02 PM GMT+00:00
model"anthropic/claude-4.5-sonnet-20250929" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency2621
moderation_latency201
generation_time7118
tokens_prompt35
tokens_completion209
native_tokens_prompt44
native_tokens_completion232
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" 
usage0.003612
router(null)
provider_responses
0
id"5937a442-d471-4b1f-b182-dfdad4a6c19c" 
status200
is_byokfalse
latency2620
endpoint_id"d8bee848-f020-454a-b2be-4a7ce868f99f" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-sonnet-20250929" 
api_type"completions" 
id"gen-1770566634-qXdhtcp0NjKAyL0Ob1kS" 
upstream_id"5937a442-d471-4b1f-b182-dfdad4a6c19c" 
total_cost0.003612
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
69.3968% Matches word count n/a
neededCleanfalse
sentences9
wordCounts
020
119
219
319
420
519
619
719
819