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Run: 2026-09-29-01M3P2C8N9E9GH8Q4W5GJAM51P
Run Details
Model:
Claude Sonnet 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
17.6s
Cost:
$0.022454
Provider:
Claude Platform on AWS
Evaluation summary
Score
Evaluator
Details Link
85.71%
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 hammered against the windows of Blackwood Manor as Detective Inspector Marlowe stepped inside, shaking water from his coat. A young constable met him in the marble hallway, pale and trembling, holding a notebook he had not yet opened. "Lord Ashcombe is dead, sir," the constable whispered, "found slumped over his desk in the locked library just after midnight." Marlowe followed him down the corridor, past portraits of stern ancestors whose painted eyes seemed to watch every hesitant step. Inside the library the fire still crackled, and the old man sat rigid in his chair, clutching a brass key. Marlowe knelt beside the body and noticed a smell of bitter almonds lingering around the empty glass on the desk. The door was locked from the inside, the windows were bolted, and yet somebody had clearly wanted Ashcombe silenced tonight. Somewhere close behind him, a floorboard creaked, and Marlowe realized that the killer might still be standing inside the house.
created_at
"2026-09-29T07:51:57.362Z"
9/29/2026, 7:51:57 AM
model
"anthropic/claude-sonnet-5.5-20260928"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3682
moderation_latency
(null)
generation_time
17562
tokens_prompt
46
tokens_completion
501
native_tokens_prompt
62
native_tokens_completion
2233
native_tokens_completion_images
(null)
native_tokens_reasoning
1900
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
0.022454
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.21.0; linux; x64))"
http_referer
(null)
request_id
"req-1790668317-owTU5i2LpEXo9C20vR4J"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790668317-Levo1lUU2C9tNcfBROWO"
upstream_id
"msg_011CfXNFiE3f5n9xYsf3heZS"
provider_responses
0
endpoint_id
"99aaad94-923b-4fc1-b763-271ed5486f7a"
id
"msg_011CfXNFiE3f5n9xYsf3heZS"
is_byok
false
latency
735
model_permaslug
"anthropic/claude-sonnet-5.5-20260928"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.022454
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
85.71%
Matches word count
n/a
neededClean
false
sentences
7
wordCounts
0
20
1
20
2
40
3
20
4
20
5
20
6
20