NC Bench
Overview
About
Tests
Models
Model
Claude Haiku 4.5
Test
N-Length Sentences
Scenario
Write sentences with 20 words each
Run ID
2026-02-08-01KGYZPSES8589BTTZR829YVM6
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 Body on the Library Floor Detective Sarah Chen arrived at Ashworth Manor just as the rain began falling heavily on the ancient grounds. Lord Ashworth lay sprawled across the Persian rug, a letter opener protruding from between his shoulder blades. His face was frozen in an expression of shock and surprise, suggesting the attack had been swift and totally unexpected. The butler, Mr. Graves, stood trembling in the doorway, wringing his hands as tears streamed down his weathered face. "He was alive just thirty minutes ago," Graves whispered hoarsely, his voice barely audible above the sound of the storm. Sarah knelt beside the body, careful not to disturb the crime scene with her coat or her steady hands. The letter opener bore the Ashworth family crest, suggesting the murderer had intimate knowledge of this house and its secrets. Through the library's tall windows, lightning illuminated the faces of three suspects who had all been present tonight. Lady Ashworth stood near the fireplace, her expression unreadable, while her nephew paced nervously near the bookshelf. The victim's business partner, Mr. Blackwood, sat rigidly in a leather chair, his knuckles white from gripping its wooden arms.
created_at
"2026-02-08T16:00:15.761845+00:00"
Sunday, February 8th, 2026 at 4:00:15 PM GMT+00:00
model
"anthropic/claude-4.5-haiku-20251001"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
517
moderation_latency
(null)
generation_time
3229
tokens_prompt
35
tokens_completion
244
native_tokens_prompt
44
native_tokens_completion
272
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
0.001404
router
(null)
provider_responses
0
id
"msg_01QZCNa9fPkWX9LcTjgvnShC"
status
200
is_byok
false
latency
505
endpoint_id
"41d2915a-92e6-4993-b537-210b4e10cba8"
provider_name
"Anthropic"
model_permaslug
"anthropic/claude-4.5-haiku-20251001"
api_type
"completions"
id
"gen-1770566411-thQu5r48Xbl8xvaHdH8h"
upstream_id
"msg_01QZCNa9fPkWX9LcTjgvnShC"
total_cost
0.001404
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
Evaluation details
Result
Evaluator
Details
Meta Data
50.0541%
Matches word count
n/a
neededClean
false
sentences
11
wordCounts
0
7
1
18
2
17
3
20
4
19
5
20
6
19
7
20
8
18
9
17
10
20