NC Bench
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Run: 2026-02-20-01KHY8E38Z11BRSB7KAFG308HD
Run Details
Model:
Grok 4.1 Fast
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
5.3s
Cost:
$0.000278
Provider:
xAI
Evaluation summary
Score
Evaluator
Details Link
0.13%
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
Fog shrouded the ancient mansion on the hill as thunder rumbled ominously in the distance that night. Guests arrived in luxury cars, their laughter echoing through the grand foyer filled with crystal chandeliers. Sir Reginald Blackwood greeted them warmly, his eyes hiding secrets beneath a charming, aristocratic smile. The dinner party began with fine wine flowing freely amid conversations of wealth and hidden rivalries. Suddenly, a piercing scream shattered the evening from the library down the dimly lit hallway. Servants rushed forward while guests froze in terror at the unexpected, horrifying interruption of festivities. Lady Eleanor burst from the library door, her face pale with blood staining her elegant gown. "Reginald is dead!" she cried out, pointing back inside where horror awaited the stunned assembly. Detective Harlan Graves arrived swiftly, his trench coat damp from rain as he assessed the scene. The body lay slumped over the desk, a poisoned chalice clutched tightly in the victim's hand.
created_at
"2026-02-20T19:29:11.469Z"
2/20/2026, 7:29:11 PM
model
"x-ai/grok-4.1-fast"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1419
moderation_latency
(null)
generation_time
5231
tokens_prompt
46
tokens_completion
320
native_tokens_prompt
191
native_tokens_completion
524
native_tokens_completion_images
0
native_tokens_reasoning
336
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
0.00027755
router
(null)
provider_responses
0
endpoint_id
"9821aa0e-dce3-4c27-9716-161359123d0b"
id
"49fc6a90-2c56-5a3a-43e8-d766ee630a40"
is_byok
false
latency
1211
model_permaslug
"x-ai/grok-4.1-fast"
provider_name
"xAI"
status
200
api_type
"completions"
id
"gen-1771615751-pd5H22dww92mNEonoaBI"
upstream_id
"49fc6a90-2c56-5a3a-43e8-d766ee630a40"
total_cost
0.00027755
cache_discount
0.00002265
upstream_inference_cost
0
provider_name
"xAI"
Evaluation details
Result
Evaluator
Details
Meta Data
0.13%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
17
1
16
2
15
3
16
4
15
5
15
6
16
7
15
8
16
9
16