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Run: 2026-05-31-01KSYXD93F0MF0RTK0HG29QK6N
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
26.1s
Cost:
$0.069875
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 20 words. Please make sure that each sentence has the same length. Only return the opening itself.
Model response
Messages
Meta
AI
The rain fell heavily against the old manor windows, blurring the dim glow of the streetlamps lining the gravel drive. Detective Sarah Mills stepped out from her car, pulling her thin coat tighter against the cold, unforgiving wind howling outside. Inside the grand hall, the body of the wealthy patriarch Charles Whitmore lay sprawled across the cold marble floor, lifeless. A single crystal goblet rested beside his outstretched hand, its dark contents spilled and staining the expensive Persian rug nearby. Five nervous guests huddled together near the fireplace, their faces pale with shock, none daring to speak the obvious truth. Sarah knelt down beside the corpse, examining the faint blue tinge around his lips, certain this death was no accident. Someone inside this very room had carefully planned and executed a cold murder, and she intended to expose them tonight.
created_at
"2026-05-31T11:41:19.357Z"
5/31/2026, 11:41:19 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3624
moderation_latency
(null)
generation_time
26058
tokens_prompt
46
tokens_completion
398
native_tokens_prompt
60
native_tokens_completion
2783
native_tokens_completion_images
(null)
native_tokens_reasoning
168
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
0.069875
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01L2T5p5C76xqh23eGD8Bhtq"
is_byok
false
latency
1157
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-1780227679-IxxnmipioZkyLtLCi2AH"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227679-JUReBb3SX1NxV9Kfwdzi"
upstream_id
"msg_01L2T5p5C76xqh23eGD8Bhtq"
total_cost
0.069875
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
7
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20