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Run: 2026-05-29-01KSSK5GPDFFNSR2Y8BW1EKTQX
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 10 words each
Duration:
21.6s
Cost:
$0.045100
Provider:
Anthropic
Evaluation summary
Score
Evaluator
Details Link
100.00%
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
Rain hammered against the old mansion's tall and dusty windows. Detective Mara Voss stepped slowly inside, shaking off the cold. A man's body lay sprawled across the cold marble floor. Blood pooled beneath him, dark and still slowly spreading outward. The grandfather clock struck midnight as she knelt down quietly. Five guests waited upstairs, none of them yet truly aware. Mara studied the victim's face and felt her stomach tighten. She recognized him instantly from the morning's troubling newspaper headline. Senator Harold Crane, found dead inside his own locked study. The heavy door had been bolted firmly from the inside. Yet someone had somehow managed to kill him regardless tonight. Mara stood up, brushing dust from her knees, frowning deeply. This would surely be the hardest case of her career.
created_at
"2026-05-29T10:06:07.064Z"
5/29/2026, 10:06:07 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
7246
moderation_latency
(null)
generation_time
21591
tokens_prompt
46
tokens_completion
313
native_tokens_prompt
60
native_tokens_completion
1792
native_tokens_completion_images
(null)
native_tokens_reasoning
110
native_tokens_cached
0
num_media_prompt
(null)
num_input_audio_prompt
(null)
num_media_completion
0
num_search_results
(null)
num_fetches
(null)
web_search_engine
(null)
origin
"https://ncbench.com/"
is_byok
false
finish_reason
"stop"
native_finish_reason
"end_turn"
service_tier
"default"
usage
0.0451
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01LfcroK7XbASAsBQaav5T61"
is_byok
false
latency
4567
model_permaslug
"anthropic/claude-4.8-opus-20260528"
provider_name
"Anthropic"
status
200
user_agent
"langchainjs-openai/1.0.0 ((node/v24.16.0; linux; x64))"
http_referer
(null)
request_id
"req-1780049167-xjkV13gUROUw63OuEXw0"
session_id
(null)
api_type
"completions"
id
"gen-1780049167-Fle6F7FiPQ0SCGkXmCxS"
upstream_id
"msg_01LfcroK7XbASAsBQaav5T61"
total_cost
0.0451
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
response_cache_source_id
(null)
Evaluation details
Result
Evaluator
Details
Meta Data
100.00%
Matches word count
n/a
neededClean
false
sentences
13
wordCounts
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
10
8
10
9
10
10
10
11
10
12
10