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Run: 2026-09-23-01M37PERXWC8G3FT514BB9HJZM
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
24.0s
Cost:
$0.050208
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 rain had not stopped for three days when Inspector Clara Venn arrived at the iron gates of Blackmoor House. A young constable waited beneath a black umbrella, his face pale and his hands trembling as he opened the door. She stepped out into the mud and looked up at the dark windows, where only one light still burned faintly. "The body is in the library, ma'am," the constable said quietly, as though afraid the house itself might overhear him. Clara followed him through the grand hallway, past portraits of stern ancestors whose painted eyes seemed to track every step. Lord Edmund Ashcroft lay face down beside the cold fireplace, a silver letter opener buried deep between his broad shoulders. The fire had long since died, yet the room smelled of smoke, lavender, and something sharper she could not name. "Who found him?" she asked, kneeling beside the corpse without disturbing the scattered papers that surrounded him like fallen leaves. "The butler did, just after midnight, but he swears the door was locked from the inside when he first arrived." Clara rose, glanced at the only window, and noticed that its heavy latch had been fastened with a black ribbon. "Somebody wanted us to believe this was impossible," she murmured, "and somebody in this house is still very much awake."
created_at
"2026-09-23T17:54:14.605Z"
9/23/2026, 5:54:14 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4435
moderation_latency
(null)
generation_time
23942
tokens_prompt
46
tokens_completion
735
native_tokens_prompt
62
native_tokens_completion
2498
native_tokens_completion_images
(null)
native_tokens_reasoning
2076
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
0.050208
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186054-H9i8Z14ckuM3C71C1eul"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186054-dtlDe8DN7wT5X52HAsiK"
upstream_id
"msg_011CfLoL3RvmwM7uptC42mdQ"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLoL3RvmwM7uptC42mdQ"
is_byok
false
latency
1288
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.050208
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
11
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20
8
20
9
20
10
20