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Run: 2026-09-23-01M37PTTBDPS3G9NCA0DQ44XEC
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
22.4s
Cost:
$0.046968
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 winter storm had been battering Blackwood Manor for three hours when the lights flickered once and then died completely. In the sudden darkness, eleven guests froze around the dining table, their silverware suspended above plates of cooling roast duck. Somewhere upstairs, a door slammed with such force that the crystal chandelier above them trembled and chimed like nervous laughter. Margaret Ashford, the elderly hostess, was the first to speak, and her voice carried a sharpness nobody had heard before. "Nobody move," she said, striking a match that briefly illuminated her pale face and the empty velvet chair beside her. That chair belonged to her nephew Julian, who had excused himself ten minutes earlier to fetch another bottle of wine. Doctor Harwell pushed back his seat, muttering about fuses, but Margaret seized his wrist with surprising strength for her age. Then came the scream, long and ragged, spilling down the grand staircase and echoing through every corridor of the house. By the time they reached the library, candles trembling in their hands, the maid was kneeling beside Julian's motionless body. A silver letter opener protruded from his chest, and clutched in his hand was a torn page from Margaret's diary. Every frightened face turned slowly toward their hostess, who stared at the page as though she had seen a ghost.
created_at
"2026-09-23T18:00:49.278Z"
9/23/2026, 6:00:49 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4457
moderation_latency
(null)
generation_time
22379
tokens_prompt
46
tokens_completion
567
native_tokens_prompt
62
native_tokens_completion
2336
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
0.046968
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790186449-QNkpHXIjyIa5BcqWpwA9"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790186449-EPQUZVMGPbRrBC3wsb9R"
upstream_id
"msg_011CfLoq9TPK2cN4LronG517"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLoq9TPK2cN4LronG517"
is_byok
false
latency
1389
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.046968
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