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Run: 2026-05-29-01KSSJHKCSSEPHQRSSVE5S9DFJ
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
45.9s
Cost:
$0.128925
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 cold rain fell heavily against the old mansion windows as Detective Sarah Mills stepped onto the creaking wooden porch. Inside the dimly lit study, the body of the wealthy businessman Charles Harrington lay sprawled across the ornate Persian rug. A single bullet wound had marked the victim's chest, and shattered glass glittered ominously beneath the flickering antique chandelier above. Sarah knelt down beside the lifeless body very carefully, her trained eyes scanning every detail of the gruesome bloody scene. The mansion belonged to a powerful family with countless secrets, and tonight one of those dangerous secrets had finally surfaced. Outside, thunder rumbled loudly across the darkened sky as five nervous guests waited anxiously inside the grand drawing room together. Each one of them had a clear motive, a hidden grudge, and absolutely no convincing alibi for this terrible night. Sarah took a deep, steadying breath, knowing that catching this clever killer would test every skill she had ever learned.
created_at
"2026-05-29T09:55:14.468Z"
5/29/2026, 9:55:14 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3835
moderation_latency
(null)
generation_time
45876
tokens_prompt
46
tokens_completion
571
native_tokens_prompt
60
native_tokens_completion
5145
native_tokens_completion_images
(null)
native_tokens_reasoning
303
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
0.128925
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01Vehcequ1bsGLvGhkfgmaem"
is_byok
false
latency
1017
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-1780048514-ynYttMT9946n3cQM6D3j"
session_id
(null)
api_type
"completions"
id
"gen-1780048514-o1EzAPa80UPG1lSVBL7Q"
upstream_id
"msg_01Vehcequ1bsGLvGhkfgmaem"
total_cost
0.128925
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
8
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20