NC Bench
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Run: 2026-02-20-01KHY7TZ3ZDQKB2WA08B1TH76Z
Run Details
Model:
Grok 4 Fast
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
3.7s
Cost:
$0.000284
Provider:
xAI
Evaluation summary
Score
Evaluator
Details Link
8.31%
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 rain hammered relentlessly against the fog-shrouded windows of Blackwood Manor on that fateful autumn evening. Detective Elias Thorne arrived just as lightning illuminated the sprawling estate's gothic silhouette against the stormy sky. He stepped from his car, umbrella futile against the wind-whipped downpour soaking his trench coat instantly. The butler, pale and trembling, greeted him at the creaking oak door with a whispered urgent plea for help. Inside the grand foyer, crystal chandeliers cast flickering shadows on portraits of stern ancestors lining the walls. Thorne followed the servant up the winding staircase, his footsteps echoing like ominous drumbeats in the silence. At the bedroom door, a metallic tang of blood hung heavy in the air, turning his stomach slightly. Pushing it open, he beheld Lady Victoria Harrington sprawled lifeless on the Persian rug by the fireplace. Her emerald gown was torn and stained crimson, throat slashed in a brutal, precise arc of violence. No weapon lay nearby, only shattered vase fragments and a single pearl earring glinting in the lamplight.
created_at
"2026-02-20T19:18:44.619Z"
2/20/2026, 7:18:44 PM
model
"x-ai/grok-4-fast"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
2020
moderation_latency
(null)
generation_time
3156
tokens_prompt
46
tokens_completion
287
native_tokens_prompt
191
native_tokens_completion
537
native_tokens_completion_images
0
native_tokens_reasoning
316
native_tokens_cached
152
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
"completed"
usage
0.0002839
router
(null)
provider_responses
0
endpoint_id
"c9586d9d-97ff-40ca-ae94-22504d6f9b7e"
id
"8ddd4e9f-6eec-fd10-45dc-80b5e7e4f929"
is_byok
false
latency
248
model_permaslug
"x-ai/grok-4-fast"
provider_name
"xAI"
status
200
api_type
"completions"
id
"gen-1771615124-KGh3EIa4fg9lWRC5tIPP"
upstream_id
"8ddd4e9f-6eec-fd10-45dc-80b5e7e4f929"
total_cost
0.0002839
cache_discount
0.0000228
upstream_inference_cost
0
provider_name
"xAI"
Evaluation details
Result
Evaluator
Details
Meta Data
8.31%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
17
1
17
2
17
3
19
4
17
5
17
6
18
7
17
8
17
9
17