NC Bench
Overview
About
Tests
Categories
Models
Vendors
Compare
Run: 2026-09-23-01M37NYMCEQYE7PWPK3B708C7R
Run Details
Model:
Claude Opus 5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 10 words each
Duration:
18.3s
Cost:
$0.035888
Provider:
Claude Platform on AWS
Evaluation summary
Score
Evaluator
Details Link
93.75%
Matches word count
(details)
Model input
User/Human
Please write the opening scene of a murder mystery where each sentence has exactly 10 words. Please make sure that each sentence has the same length. Only return the opening itself.
Model response
Messages
Meta
AI
The storm arrived at Blackwood Manor just after midnight struck. Lightning split the sky above the old stone chapel roof. Inside, the guests had gathered near the dying library fire. Nobody noticed when Lord Ashford quietly slipped away from them. The grandfather clock in the hallway chimed a single time. Then a scream echoed through the long corridors of stone. Margaret, the housekeeper, stood trembling at the open study door. Her candle shook, casting wild shadows across the paneled walls. Lord Ashford lay sprawled beside his desk, eyes staring upward. A silver letter opener protruded cleanly from his motionless chest. Detective Eleanor Graves pushed past the gasping guests without hesitation. She knelt beside the body and studied the strange wound. The window was locked, and the fireplace held only ash. Whoever killed him had walked in through the only door. Eleanor rose slowly and turned to face the frightened crowd. "One of you," she said quietly, "is a cold murderer." Outside, the storm raged on, sealing them all inside together.
created_at
"2026-09-23T17:45:25.662Z"
9/23/2026, 5:45:25 PM
model
"anthropic/claude-opus-5.5-20260921"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4958
moderation_latency
(null)
generation_time
18254
tokens_prompt
46
tokens_completion
486
native_tokens_prompt
62
native_tokens_completion
1782
native_tokens_completion_images
(null)
native_tokens_reasoning
1420
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
0.035888
router
(null)
user_agent
"langchainjs-openai/1.0.0 ((node/v24.20.0; linux; x64))"
http_referer
(null)
request_id
"req-1790185525-iRyZxmcHmOzcc8dNdVsn"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1790185525-W0gPHsUwk9cVXVIdBKel"
upstream_id
"msg_011CfLnf4teoJimBJZxpX9f6"
provider_responses
0
endpoint_id
"3a2388bc-3740-4e64-a1f5-4e301726b6b9"
id
"msg_011CfLnf4teoJimBJZxpX9f6"
is_byok
false
latency
1459
model_permaslug
"anthropic/claude-opus-5.5-20260921"
provider_name
"Claude Platform on AWS"
status
200
total_cost
0.035888
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
93.75%
Matches word count
n/a
neededClean
false
sentences
16
wordCounts
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
10
8
10
9
10
10
10
11
10
12
10
13
10
14
10
15
20