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Run: 2026-09-23-01M37Q7D2DR4JXGX9STA45ZHRX
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
26.9s
Cost:
$0.051668
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 already knocked out the power when Margaret Hale found her husband lying dead beneath the library window. She stood in the doorway holding a trembling candle, watching wax drip slowly onto the old polished oak floorboards below. Edward was sprawled across the Persian rug, one arm outstretched toward the fireplace as if desperately reaching for something important. A stain spread from beneath his head, and beside him lay the brass poker that usually hung by the hearth. Thunder rolled over the moors, rattling the tall windows, and somewhere upstairs a door slammed shut with sudden, terrible violence. Margaret did not scream, because she knew eleven guests were sleeping under this roof tonight, and one was a killer. Instead, she knelt beside Edward and pried open his clenched fist, where she found a torn scrap of yellowed paper. Three words were written there in faded ink, and the handwriting belonged unmistakably to her beloved younger sister, Lydia Ashford. Lydia had drowned in the lake behind this very house exactly twelve years ago, on the night before Margaret's wedding. Holding the scrap closer to the flame, Margaret read the message twice, and her blood ran cold: I remember everything.
created_at
"2026-09-23T18:07:41.659Z"
9/23/2026, 6:07:41 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4216
moderation_latency
(null)
generation_time
26894
tokens_prompt
46
tokens_completion
707
native_tokens_prompt
62
native_tokens_completion
2571
native_tokens_completion_images
(null)
native_tokens_reasoning
2168
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
0.051668
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186861-AzNuxrZw15NAN90uDLFE"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186861-0afR2ApRX65kXGcaIOxA"
upstream_id
"msg_011CfLpMY22tmQGyBvgFYX1x"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLpMY22tmQGyBvgFYX1x"
is_byok
false
latency
1276
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.051668
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
10
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20
8
20
9
20