Model

Claude Opus 4.5

Test

N-Length Sentences

Scenario

Write sentences with 20 words each

Run ID

2026-02-08-01KGYX45CVDPCX66BMQS2PCHP9

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 fell steadily on the cobblestone streets of Whitmore village as midnight approached the old abandoned textile mill nearby. Detective Sarah Chen stepped out of her vehicle and walked carefully toward the yellow police tape surrounding the scene. A body lay crumpled beneath the ancient oak tree where children had once played their innocent games so long ago. The victim was male, approximately forty years old, wearing an expensive suit that seemed entirely out of place around here. His eyes stared blankly at the stormy sky above while blood pooled beneath his head on the wet ground. Officer James Murphy approached her with a grim expression and handed over a small plastic evidence bag containing something peculiar. Inside was a single playing card, the queen of spades, with strange symbols drawn carefully in red ink on it. Sarah had seen this calling card before, exactly three years ago, when the Whitmore Strangler had terrorized this sleepy town. Everyone believed that killer was dead, buried in the cemetery on the hill after a dramatic confrontation with police. Now she wondered if they had caught the wrong person or if someone new was copying those terrible crimes precisely.
created_at"2026-02-08T15:15:13.018275+00:00" Sunday, February 8th, 2026 at 3:15:13 PM GMT+00:00
model"anthropic/claude-4.5-opus-20251124" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1480
moderation_latency(null)
generation_time8363
tokens_prompt35
tokens_completion225
native_tokens_prompt44
native_tokens_completion239
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" 
usage0.006195
router(null)
provider_responses
0
id"msg_014VFd8qhhHypDURTYGUnqs8" 
status200
is_byokfalse
latency1480
endpoint_id"be883404-eb42-4b2d-b6e4-c7daa3aa8d62" 
provider_name"Anthropic" 
model_permaslug"anthropic/claude-4.5-opus-20251124" 
api_type"completions" 
id"gen-1770563704-I9N9VywNccVal6vLcCr9" 
upstream_id"msg_014VFd8qhhHypDURTYGUnqs8" 
total_cost0.006195
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic" 

Evaluation details

Result Evaluator Details Meta Data
88.1959% Matches word count n/a
neededCleanfalse
sentences10
wordCounts
020
119
220
320
419
520
620
720
819
920