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Run: 2026-09-23-01M37PTYM2DF4ARH5277RE2TA8
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
19.3s
Cost:
$0.037968
Provider:
Claude Platform on AWS
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 storm had been raging over Blackwood Manor for three days when the butler finally discovered the lifeless body upstairs. Lord Edmund Harrow lay slumped across his mahogany desk, a silver letter opener buried deep between his broad shoulder blades. Candles had burned down to nothing, leaving only the cold gray light of dawn creeping through the tall arched windows. Jenkins, who had served the family faithfully for forty years, dropped his tray and let out a strangled, horrified cry. Within minutes, the remaining guests had gathered in the narrow doorway, their faces pale and their eyes wide with fear. Nobody could leave, because the only bridge connecting the island to the mainland had collapsed during the night's violent storm. Detective Clara Voss stepped forward, studying the room with the patient attention of someone who expected to be lied to. She noticed the untouched glass of brandy, the overturned chair, and the muddy footprints leading toward the locked balcony door. "One of you killed him," she said, "and before this storm ends, I promise you I will know exactly who."
created_at
"2026-09-23T18:00:53.649Z"
9/23/2026, 6:00:53 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3704
moderation_latency
(null)
generation_time
19283
tokens_prompt
46
tokens_completion
539
native_tokens_prompt
62
native_tokens_completion
1886
native_tokens_completion_images
(null)
native_tokens_reasoning
1530
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
0.037968
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186453-n0iAl5x91fGwix11Pcmg"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186453-oIPn5xo7qHq9nKVYkeJM"
upstream_id
"msg_011CfLoqTP93cXVqy9VZmegy"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLoqTP93cXVqy9VZmegy"
is_byok
false
latency
1112
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.037968
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Claude Platform on AWS"
response_cache_source_id
(null)
data_region
"global"
workspace_id
"97e315e5-d303-487d-83c1-83180e8a13d4"
Evaluation details
Result
Evaluator
Details
Meta Data
100.00%
Matches word count
n/a
neededClean
false
sentences
9
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20
8
20