NC Bench
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Run: 2026-02-18-01KHQ93J1Q5QVM5MTMQJ84SNA7
Run Details
Model:
Claude Sonnet 4.6
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
7.0s
Cost:
$0.003897
Provider:
Anthropic
Evaluation summary
Score
Evaluator
Details Link
22.70%
Matches word count
(details)
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 lighthouse stood alone on the cliff, its beam cutting through the thick, suffocating fog below. Detective Clara Marsh arrived at the scene just as the sun began its slow, reluctant rise above the horizon. She stepped carefully over the yellow tape, her boots crunching on the wet gravel path leading inside. The body of renowned art collector Edmund Price lay sprawled across the cold, unforgiving stone floor within. His eyes were wide open, staring at nothing, frozen in an expression that suggested profound and terrible surprise. A single red rose had been placed delicately on his chest, its petals still impossibly, disturbingly fresh. Clara crouched down beside him, pulling on her gloves, studying every small detail with her sharp, practiced eyes. The lighthouse keeper, an old man named Silas, stood trembling in the corner, clutching his weathered cap tightly. He claimed he had found the body at midnight, though something about his story felt deeply and profoundly wrong. Clara stood up slowly, surveying the circular room, knowing with grim certainty that nothing here was accidental at all.
created_at
"2026-02-18T02:26:21.180049+00:00"
2/18/2026, 2:26:21 AM
model
"anthropic/claude-4.6-sonnet-20260217"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
462
moderation_latency
(null)
generation_time
6963
tokens_prompt
46
tokens_completion
294
native_tokens_prompt
44
native_tokens_completion
251
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
0.003897
router
(null)
provider_responses
0
id
"msg_01X3867WznuYg9U5CkTApAhq"
status
200
is_byok
false
latency
446
endpoint_id
"6d408764-7dd7-4626-bb87-a6cc1589bc86"
provider_name
"Anthropic"
model_permaslug
"anthropic/claude-4.6-sonnet-20260217"
api_type
"completions"
id
"gen-1771381573-zhVFnAJV2a5izxv5b8A1"
upstream_id
"msg_01X3867WznuYg9U5CkTApAhq"
total_cost
0.003897
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
Evaluation details
Result
Evaluator
Details
Meta Data
22.70%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
17
1
19
2
17
3
17
4
18
5
17
6
18
7
18
8
19
9
19