NC Bench
Overview
About
Tests
Models
Model
Claude Sonnet 4.5
Test
N-Length Sentences
Scenario
Write sentences with 20 words each
Run ID
2026-02-08-01KGZ05SJ74ZJ7JKMYPXYSSPYJ
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 Velvet Room The grand chandelier cast dancing shadows across the marble floor as thunder rolled through the dark September night outside. Detective Sarah Chen stepped over the velvet rope, her practiced eyes already cataloging every detail of the opulent crime scene. The victim lay sprawled beside the mahogany desk, still wearing his tuxedo, a dark stain spreading across the pristine carpet. "Harrison Blackwood, age fifty-two, found by his wife at approximately ten fifteen," Officer Martinez recited from his small leather notebook. Sarah knelt beside the body, noting the peculiar angle of the head and the faint scent of almonds lingering. The study's French doors stood open despite the storm, rain soaking the Persian rug and puddling near the victim's outstretched hand. A crystal glass lay shattered nearby, its contents mixing with rainwater, creating small rivers that wound toward the antique bookshelf. "Where is Mrs. Blackwood now?" Sarah asked, standing slowly, her knees protesting after the long day of previous investigations and meetings. "Upstairs in the master bedroom with the family physician. She was quite hysterical when we arrived," Martinez replied, glancing nervously. Sarah walked to the open doors, observing muddy footprints that led from outside, crossed the study, then disappeared into the hallway. The mansion held twenty rooms, fifteen potential suspects attending tonight's charity gala, and one dead billionaire who knew too many secrets.
created_at
"2026-02-08T16:08:31.827154+00:00"
Sunday, February 8th, 2026 at 4:08:31 PM GMT+00:00
model
"anthropic/claude-4.5-sonnet-20250929"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1359
moderation_latency
196
generation_time
7307
tokens_prompt
35
tokens_completion
285
native_tokens_prompt
44
native_tokens_completion
332
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
0.005112
router
(null)
provider_responses
0
id
"b1f5e178-7264-431a-aebd-0b3dd8060bed"
status
200
is_byok
false
latency
1357
endpoint_id
"d8bee848-f020-454a-b2be-4a7ce868f99f"
provider_name
"Amazon Bedrock"
model_permaslug
"anthropic/claude-4.5-sonnet-20250929"
api_type
"completions"
id
"gen-1770566903-rAxuVGJBxqhifch4Eww3"
upstream_id
"b1f5e178-7264-431a-aebd-0b3dd8060bed"
total_cost
0.005112
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Amazon Bedrock"
Evaluation details
Result
Evaluator
Details
Meta Data
68.7143%
Matches word count
n/a
neededClean
false
sentences
12
wordCounts
0
4
1
19
2
20
3
20
4
21
5
19
6
21
7
20
8
21
9
20
10
21
11
21