NC Bench
Overview
About
Tests
Models
Model
Claude Opus 4.5
Test
N-Length Sentences
Scenario
Write sentences with 20 words each
Run ID
2026-02-08-01KGYZ5HHYWNP37Q070D9HKEWT
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 old grandfather clock struck midnight precisely as Detective Sarah Chen stepped into the dimly lit Victorian mansion's foyer. Rain hammered against the tall windows while thunder rumbled ominously in the distance, shaking the ancient wooden floorboards beneath her. A butler with hollow eyes and pale skin gestured silently toward the grand staircase leading up to the crime scene. The victim lay sprawled across an expensive Persian rug, a jeweled letter opener protruding grotesquely from his chest, blood pooling everywhere. Lord Ashworth had been wealthy, powerful, and despised by nearly everyone who had ever crossed paths with him in life. His widow stood motionless by the fireplace, her black dress perfectly pressed, her expression revealing absolutely nothing about her inner thoughts. Three guests had been staying at the estate that fateful weekend, and each one possessed compelling reasons to want him dead. Detective Chen pulled out her worn leather notebook, knowing that somewhere among these privileged suspects lurked a calculating and ruthless killer.
created_at
"2026-02-08T15:50:53.845123+00:00"
Sunday, February 8th, 2026 at 3:50:53 PM GMT+00:00
model
"anthropic/claude-4.5-opus-20251124"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1687
moderation_latency
178
generation_time
6528
tokens_prompt
35
tokens_completion
198
native_tokens_prompt
44
native_tokens_completion
223
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
0.005795
router
(null)
provider_responses
0
id
"cbfebfd5-5e74-45ab-ab92-72adc1265e3c"
status
200
is_byok
false
latency
1686
endpoint_id
"de32581c-2e11-4f54-8d29-e8a6e19d3038"
provider_name
"Amazon Bedrock"
model_permaslug
"anthropic/claude-4.5-opus-20251124"
api_type
"completions"
id
"gen-1770565846-EEFmoIV6BIlgg0gmgNGw"
upstream_id
"cbfebfd5-5e74-45ab-ab92-72adc1265e3c"
total_cost
0.005795
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Amazon Bedrock"
Evaluation details
Result
Evaluator
Details
Meta Data
75.4082%
Matches word count
n/a
neededClean
false
sentences
8
wordCounts
0
19
1
20
2
20
3
21
4
20
5
21
6
21
7
21