NC Bench
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Run: 2026-02-20-01KHYB818MWRWDSYNQY42P1BD9
Run Details
Model:
Grok 4.1 Fast
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
12.5s
Cost:
$0.001075
Provider:
xAI
Evaluation summary
Score
Evaluator
Details Link
0.68%
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
Thick fog enveloped the long winding driveway that led to the grand Blackwood estate where guests arrived. Elegant cars pulled up one by one as attendees in formal attire stepped out cautiously into mist. Inside the opulent ballroom of Blackwood Manor, crystal chandeliers sparkled brightly above the laughing crowd mingling freely. Champagne flutes clinked merrily in gloved hands while whispers of inheritance buzzed among the gathered aristocrats tonight. A blood-curdling scream suddenly pierced the festive air echoing loudly from the upstairs master bedroom suite. Guests froze in utter shock before rushing chaotically up the grand marble staircase to investigate hurriedly. They burst into the bedroom door and found the host lying lifeless on the Persian rug. A single silver dagger protruded from his chest amid shattered glass from the broken window nearby. Whispers of murder spread quickly among the stunned aristocrats gathered around the gruesome crime scene inside. The sharp-eyed Detective Harlan Graves arrived promptly as thunder rumbled ominously outside the ancient Blackwood Manor.
created_at
"2026-02-20T20:18:18.526Z"
2/20/2026, 8:18:18 PM
model
"x-ai/grok-4.1-fast"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
266
moderation_latency
(null)
generation_time
12342
tokens_prompt
46
tokens_completion
544
native_tokens_prompt
191
native_tokens_completion
2119
native_tokens_completion_images
0
native_tokens_reasoning
1917
native_tokens_cached
151
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
0.00107505
router
(null)
provider_responses
0
endpoint_id
"9821aa0e-dce3-4c27-9716-161359123d0b"
id
"fbd1bdcb-01b3-309c-1fd4-0496741fc236"
is_byok
false
latency
64
model_permaslug
"x-ai/grok-4.1-fast"
provider_name
"xAI"
status
200
api_type
"completions"
id
"gen-1771618698-6RGCgc8BPRsswMJkHhaO"
upstream_id
"fbd1bdcb-01b3-309c-1fd4-0496741fc236"
total_cost
0.00107505
cache_discount
0.00002265
upstream_inference_cost
0
provider_name
"xAI"
Evaluation details
Result
Evaluator
Details
Meta Data
0.68%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
17
1
17
2
17
3
17
4
17
5
16
6
16
7
16
8
16
9
17