NC Bench
Overview
About
Tests
Models
Model
Claude Sonnet 4.5
Test
N-Length Sentences
Scenario
Write sentences with 20 words each
Run ID
2026-02-08-01KGYY8RT2B493E2W2H5ZSPA2T
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
Messages
Meta
AI
# The Venetian Mask The body lay sprawled beneath the crystal chandelier, a crimson pool spreading slowly across the polished white marble floor of the grand ballroom. Detective Sarah Chen stepped carefully around the blood, her keen eyes absorbing every detail of the macabre scene before her that cold morning. The victim wore an elaborate Venetian mask, gold and emerald feathers still perfectly arranged despite the violent struggle that had clearly preceded death. "Time of death approximately midnight," the medical examiner announced, kneeling beside the corpse with gloved hands examining the fatal wound carefully now. Lady Catherine Ashworth stood frozen by the doorway, her silk gown rustling slightly as she trembled, unable to look away from her deceased guest. "The mask ball ended at eleven," she whispered hoarsely, her voice breaking with emotion as she clutched the doorframe for support and stability. Detective Chen turned toward her, notebook ready, and asked the question that would begin unraveling the twisted truth hidden behind elegant masks tonight. "Who left the ballroom between eleven and midnight, and more importantly, Lady Ashworth, who had reason to want Lord Blackwood dead?" she demanded firmly.
created_at
"2026-02-08T15:35:11.116352+00:00"
Sunday, February 8th, 2026 at 3:35:11 PM GMT+00:00
model
"anthropic/claude-4.5-sonnet-20250929"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1311
moderation_latency
222
generation_time
6601
tokens_prompt
35
tokens_completion
232
native_tokens_prompt
44
native_tokens_completion
264
native_tokens_completion_images
(null)
native_tokens_reasoning
0
native_tokens_cached
0
num_media_prompt
(null)
num_input_audio_prompt
(null)
num_media_completion
0
num_search_results
(null)
origin
"https://ncbench.com/"
is_byok
false
finish_reason
"stop"
native_finish_reason
"stop"
usage
0.004092
router
(null)
provider_responses
0
id
"2397cff6-e93b-4191-9e2e-5217d3ade8da"
status
200
is_byok
false
latency
1311
endpoint_id
"d8bee848-f020-454a-b2be-4a7ce868f99f"
provider_name
"Amazon Bedrock"
model_permaslug
"anthropic/claude-4.5-sonnet-20250929"
api_type
"completions"
id
"gen-1770564903-GsxJnJt19fJJNfdbHqYW"
upstream_id
"2397cff6-e93b-4191-9e2e-5217d3ade8da"
total_cost
0.004092
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Amazon Bedrock"
Evaluation details
Result
Evaluator
Details
Meta Data
2.1283%
Matches word count
n/a
neededClean
false
sentences
9
wordCounts
0
4
1
23
2
23
3
23
4
22
5
24
6
23
7
23
8
24