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Run: 2026-09-23-01M37P098A0JMACAMDD251WGR5
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
21.2s
Cost:
$0.045528
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 knocked out the power at Blackwood Manor just before midnight, leaving the guests stranded in complete darkness. Candles flickered along the grand hallway as Inspector Eleanor Vance descended the staircase, her footsteps echoing against the cold marble. She had come to the manor for a quiet weekend, but quiet weekends never seemed to last long for her. A scream suddenly pierced the silence, sharp and terrible, rising from somewhere behind the heavy oak doors of the library. Eleanor ran toward the sound, pushing past the trembling butler who stood frozen in the doorway with a silver candlestick. Inside, Lord Ashford lay slumped across his leather armchair, his eyes wide open and a dark stain spreading beneath him. His young wife, Margaret, knelt beside the body, sobbing uncontrollably while clutching a crumpled letter tightly in her shaking hand. Eleanor noticed that every window was bolted from the inside, and the fireplace grate had been sealed for many years. Behind her, the other guests gathered in hushed confusion, each face pale in the candlelight, each one a possible killer. Eleanor turned slowly to face them and said, "Nobody leaves this house until I find out who did this tonight."
created_at
"2026-09-23T17:46:19.804Z"
9/23/2026, 5:46:19 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4935
moderation_latency
(null)
generation_time
21171
tokens_prompt
46
tokens_completion
633
native_tokens_prompt
62
native_tokens_completion
2264
native_tokens_completion_images
(null)
native_tokens_reasoning
1846
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
0.045528
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790185579-YlVFC4E7u2TbPYCkZkbK"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790185579-d1tHiqQkO1YWDTITzwha"
upstream_id
"msg_011CfLnj3fb9VWPwND2tdFNB"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLnj3fb9VWPwND2tdFNB"
is_byok
false
latency
1375
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.045528
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