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Run: 2026-09-23-01M37NZB1JJ6XYQ9GVB63SXXAJ
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
17.8s
Cost:
$0.034808
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 Voss arrived at the iron gates of Hollow Manor. A single lamp burned in the upstairs window, flickering like a nervous heartbeat against the black and swollen midnight sky. The butler, a gaunt man named Pembrook, opened the door before she could knock and said absolutely nothing at all. He led her down a long corridor lined with portraits whose painted eyes seemed to follow every step she took. In the library, Lord Ashcombe lay slumped across his writing desk, a silver letter opener buried deep in his back. Clara noticed immediately that the fire was still warm, yet every window and door had been locked from the inside. Six guests waited in the drawing room, and each of them, she suspected, had a reason to want him dead. "Nobody leaves this house tonight," Clara announced, removing her soaked leather gloves slowly, "because one of you is a killer."
created_at
"2026-09-23T17:45:48.866Z"
9/23/2026, 5:45:48 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
5117
moderation_latency
(null)
generation_time
17789
tokens_prompt
46
tokens_completion
494
native_tokens_prompt
62
native_tokens_completion
1728
native_tokens_completion_images
(null)
native_tokens_reasoning
1423
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
0.034808
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790185548-trLZR6T41npKZxbY7MDk"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790185548-M9ERXMXf0x3hLHNVFY0k"
upstream_id
"msg_011CfLngm97UwqV6CuoXqGTj"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLngm97UwqV6CuoXqGTj"
is_byok
false
latency
1281
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.034808
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
8
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20