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Run: 2026-09-23-01M37Q01D81K86Q45NH1FCVVXM
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
20.8s
Cost:
$0.044928
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 Ashworth Manor. A constable waited beneath a black umbrella, his face pale and his hands trembling as he opened the car door. "The body is in the library, ma'am," he said quietly, glancing back at the dark windows of the old house. Clara nodded once and followed him up the gravel path, her boots sinking slightly into the mud with every step. Inside, the grand hall smelled of candle wax and wet wool, and somewhere a clock ticked with patient, measured indifference. Five people stood waiting near the staircase, each of them wearing the careful expression of someone with something to hide. Lord Edmund Ashworth lay slumped in a leather armchair beside the fireplace, a crystal glass shattered on the rug below. His eyes were open, fixed upon the portrait of his wife, as though she were the last thing he saw. Clara crouched beside the chair and noticed a faint smell of bitter almonds rising from the stain on his lips. "Nobody leaves this house tonight," she said, standing slowly and turning to face the silent guests gathered in the doorway. Behind her, the clock struck midnight, and for a moment every person in the room seemed to stop breathing entirely.
created_at
"2026-09-23T18:03:40.348Z"
9/23/2026, 6:03:40 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
20574
moderation_latency
(null)
generation_time
20574
tokens_prompt
46
tokens_completion
649
native_tokens_prompt
62
native_tokens_completion
2234
native_tokens_completion_images
(null)
native_tokens_reasoning
1814
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
0.044928
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186620-kyQJ8gisE1xGSlgBQJtc"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186620-cG73hJdwm2ZNrYfE9LiX"
upstream_id
"msg_011CfLp3kNRr5dafWBPNTSC5"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLp3kNRr5dafWBPNTSC5"
is_byok
false
latency
1209
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.044928
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