NC Bench
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Run: 2026-02-20-01KHY999T2XPM1T94RPTPSXKZZ
Run Details
Model:
Grok 4.1 Fast
Test:
N-Length Sentences
Scenario:
Write sentences with 10 words each
Duration:
23.8s
Cost:
$0.000955
Provider:
xAI
Evaluation summary
Score
Evaluator
Details Link
90.58%
Matches word count
(details)
Model input
User/Human
Please write the opening scene of a murder mystery where each sentence has exactly 10 words. Please make sure that each sentence has the same length. Only return the opening itself.
Model response
Messages
Meta
AI
The brilliant flash of lightning lit up the dark sky. Thunder crashed loudly, shaking windows of the old stone house. Sir Reginald Blackwood sat alone in his dimly lit study. He poured a tall glass of scotch whiskey quite slowly. The heavy oak door creaked open very late tonight. A shadowy figure slipped inside the room without any sound. Sir Reginald looked up suddenly from his leather armchair seat. The intruder drew a sharp dagger gleaming in firelight. One swift thrust pierced his chest ending life instantly. Blood pooled darkly on the Persian rug beneath his chair. Dawn light revealed the horror to the screaming housemaid.
created_at
"2026-02-20T19:44:02.896Z"
2/20/2026, 7:44:02 PM
model
"x-ai/grok-4.1-fast"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
300
moderation_latency
(null)
generation_time
23686
tokens_prompt
46
tokens_completion
500
native_tokens_prompt
191
native_tokens_completion
1890
native_tokens_completion_images
0
native_tokens_reasoning
1767
native_tokens_cached
190
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
0.0009547
router
(null)
provider_responses
0
endpoint_id
"9821aa0e-dce3-4c27-9716-161359123d0b"
id
"761e94be-f228-bf54-9124-319361f09e77"
is_byok
false
latency
139
model_permaslug
"x-ai/grok-4.1-fast"
provider_name
"xAI"
status
200
api_type
"completions"
id
"gen-1771616642-ZvJNYdY39aSag2uaJU8n"
upstream_id
"761e94be-f228-bf54-9124-319361f09e77"
total_cost
0.0009547
cache_discount
0.0000285
upstream_inference_cost
0
provider_name
"xAI"
Evaluation details
Result
Evaluator
Details
Meta Data
90.58%
Matches word count
n/a
neededClean
false
sentences
11
wordCounts
0
10
1
10
2
10
3
10
4
9
5
10
6
10
7
9
8
9
9
10
10
9