Model

Claude Sonnet 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYZKN1DEPF1NTJ7FFPV73EM

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 Last Symphony Rain hammered the conservatory windows while Detective Sarah Chen stood over the body of renowned conductor Victor Ashford, still clutching his baton tightly. Blood pooled beneath the piano, mixing with scattered sheet music that now bore crimson stains instead of musical notes alone. The orchestra members huddled together near the stage entrance, their elegant concert attire contrasting sharply with the horror etched upon faces. "Nobody leaves this building until I get answers," Sarah announced firmly, her voice cutting through the shocked silence like a knife. First violinist Margaret Winters stepped forward nervously, her hands trembling as she struggled to speak through tears streaming down her pale cheeks. "He was alive fifteen minutes ago, yelling at us during rehearsal as usual, demanding perfection for tomorrow night's prestigious performance," she whispered. Sarah's partner, Detective James Rodriguez, examined the conductor's podium carefully, noting the overturned music stand and suspicious wine glass nearby. The stage lights flickered ominously overhead, casting dancing shadows across the crime scene while thunder rolled menacingly through the darkening evening sky. Someone in this room had silenced Victor Ashford's demanding voice forever, and Sarah intended to discover exactly who and why tonight.
created_at"2026-02-08T15:58:37.132844+00:00" Sunday, February 8th, 2026 at 3:58:37 PM GMT+00:00
model"anthropic/claude-4.5-sonnet-20250929" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1773
moderation_latency147
generation_time7756
tokens_prompt35
tokens_completion239
native_tokens_prompt44
native_tokens_completion274
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" 
usage0.004242
router(null)
provider_responses
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id"2d00ab2c-51c8-473c-8f5e-513c05cb8c3c" 
status200
is_byokfalse
latency1772
endpoint_id"d8bee848-f020-454a-b2be-4a7ce868f99f" 
provider_name"Amazon Bedrock" 
model_permaslug"anthropic/claude-4.5-sonnet-20250929" 
api_type"completions" 
id"gen-1770566308-rdLmSevroZCptXQMlWZP" 
upstream_id"2d00ab2c-51c8-473c-8f5e-513c05cb8c3c" 
total_cost0.004242
cache_discount(null)
upstream_inference_cost0
provider_name"Amazon Bedrock" 

Evaluation details

Result Evaluator Details Meta Data
42.3671% Matches word count n/a
neededCleanfalse
sentences10
wordCounts
04
123
220
321
421
522
622
720
822
921