NC Bench
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Run: 2026-02-20-01KHY98ZZRDZZSW2NJ4H4MYB5P
Run Details
Model:
Grok 4.1 Fast
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
5.2s
Cost:
$0.000349
Provider:
xAI
Evaluation summary
Score
Evaluator
Details Link
22.07%
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
Mist hung heavy over Blackwood Manor as guests arrived for the annual gala under a moonless, starless sky tonight. Lady Eleanor Blackwood, the elegant hostess, greeted each one warmly in the grand foyer lit by crystal chandeliers. Suddenly, a piercing scream echoed from the library, shattering the evening's sophisticated chatter and laughter abruptly. Guests rushed toward the ornate oak door, pushing it open to reveal a horrifying sight inside the room. Lord Reginald Blackwood lay sprawled on the Persian rug, a jeweled dagger plunged deep into his unmoving chest cavity. Blood pooled around his lifeless body, staining the antique carpet in a dark, crimson circle that spread slowly. Inspector Harlan Graves arrived swiftly, his trench coat dripping rain as he surveyed the gruesome scene methodically. No one had left the manor, trapping all suspects within these fog-enshrouded walls on this fateful night.
created_at
"2026-02-20T19:43:52.838Z"
2/20/2026, 7:43:52 PM
model
"x-ai/grok-4.1-fast"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
246
moderation_latency
(null)
generation_time
5055
tokens_prompt
46
tokens_completion
288
native_tokens_prompt
191
native_tokens_completion
666
native_tokens_completion_images
0
native_tokens_reasoning
480
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
0.00034855
router
(null)
provider_responses
0
endpoint_id
"9821aa0e-dce3-4c27-9716-161359123d0b"
id
"7b2f5a03-1aa0-c7f7-8e66-03e64cced371"
is_byok
false
latency
126
model_permaslug
"x-ai/grok-4.1-fast"
provider_name
"xAI"
status
200
api_type
"completions"
id
"gen-1771616632-SQOwdNx5QlmurpVG3wuN"
upstream_id
"7b2f5a03-1aa0-c7f7-8e66-03e64cced371"
total_cost
0.00034855
cache_discount
0.00002265
upstream_inference_cost
0
provider_name
"xAI"
Evaluation details
Result
Evaluator
Details
Meta Data
22.07%
Matches word count
n/a
neededClean
false
sentences
8
wordCounts
0
19
1
18
2
16
3
18
4
19
5
18
6
17
7
18