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Run: 2026-09-23-01M37Q034SEXMP7W1DR0DQYC4F
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
18.3s
Cost:
$0.035808
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 been falling over Blackmere Manor for three days when the butler discovered the body in the library. Lord Edmund Ashworth lay slumped across his mahogany desk, a silver letter opener buried deep between his broad shoulder blades. Old Hobbs stood frozen in the doorway, his candle trembling, as thunder rolled across the moors like distant cannon fire. Within the hour, every guest had been summoned to the drawing room, where the dying fire burned low and uneasy. Inspector Margaret Hale studied each face carefully, knowing that somewhere among these seven elegant strangers sat a patient, cold-blooded killer. "Nobody leaves this house tonight," she announced quietly, and the widow in black let her teacup shatter upon the floor. Hale noticed, of course, that the woman's hands had been shaking long before anyone had even mentioned the word murder.
created_at
"2026-09-23T18:03:42.121Z"
9/23/2026, 6:03:42 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
18255
tokens_prompt
46
tokens_completion
436
native_tokens_prompt
62
native_tokens_completion
1778
native_tokens_completion_images
(null)
native_tokens_reasoning
1484
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
0.035808
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186622-QnQpA8coN5DonTZg7lfG"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186622-aipeKjl4iqHmUh0uAXdi"
upstream_id
"msg_011CfLp3skBmHTNbMGKWAbqj"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLp3skBmHTNbMGKWAbqj"
is_byok
false
latency
1164
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.035808
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
7
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20