NC Bench
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Run: 2026-02-18-01KHQ93HNJYHXE15N2B0EZCZP4
Run Details
Model:
Claude Sonnet 4.6
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
6.2s
Cost:
$0.003717
Provider:
Anthropic
Evaluation summary
Score
Evaluator
Details Link
15.76%
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 at the edge of town, its beam cutting through the thick November fog. Nobody had visited the lighthouse keeper, Mr. Aldous Finch, for three long weeks until young Sara arrived. Sara climbed the winding iron staircase slowly, her lantern casting strange dancing shadows across the cold stone walls. At the very top, she pushed open the heavy wooden door and immediately felt something was terribly wrong. The room was completely overturned, papers scattered everywhere, and a half-eaten meal sat rotting on the table. Then she saw him, slumped against the far wall, his pale hand clutching a torn red envelope. Sara pressed her back against the door frame, her breath coming out in short and desperate little gasps. She forced herself to step closer, her boots crunching on broken glass that covered the entire stone floor. The envelope in his hand bore a single word, written in dark ink that Sara prayed was not blood. Outside, the foghorn moaned across the black water, as if the sea itself already knew the terrible truth.
created_at
"2026-02-18T02:26:19.944482+00:00"
2/18/2026, 2:26:19 AM
model
"anthropic/claude-4.6-sonnet-20260217"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
442
moderation_latency
(null)
generation_time
6142
tokens_prompt
46
tokens_completion
280
native_tokens_prompt
44
native_tokens_completion
239
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
0.003717
router
(null)
provider_responses
0
id
"msg_01A2Dtig5pSD1FGNCV4q3PYH"
status
200
is_byok
false
latency
442
endpoint_id
"6d408764-7dd7-4626-bb87-a6cc1589bc86"
provider_name
"Anthropic"
model_permaslug
"anthropic/claude-4.6-sonnet-20260217"
api_type
"completions"
id
"gen-1771381573-OPxQr6yM0WEnwvIhVWh8"
upstream_id
"msg_01A2Dtig5pSD1FGNCV4q3PYH"
total_cost
0.003717
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
Evaluation details
Result
Evaluator
Details
Meta Data
15.76%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
18
1
17
2
18
3
18
4
18
5
17
6
18
7
18
8
19
9
18