NC Bench
Overview
About
Tests
Categories
Models
Vendors
Compare
Run: 2026-05-29-01KSSK256KT04AFR7WM4X7SR2P
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
34.4s
Cost:
$0.094125
Provider:
Anthropic
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 autumn rain fell softly against the old manor windows as Detective Sarah Cole stepped onto the wet gravel path. Inside the dimly lit study, the body of old Lord Harrington lay sprawled across his very expensive antique Persian carpet. A single candle flickered upon the large mahogany desk casting long shadows that danced ominously across the blood-stained wooden floor. Sarah crouched beside the silent victim, carefully noting the silver letter opener buried deep inside his chest, still warm somehow. Outside, thunder rumbled across the darkening evening sky while six nervous guests waited anxiously inside the grand dining room nearby. Each one harbored dark secrets, motives, and reasons enough to want the wealthy, cruel old man permanently and conveniently removed. Detective Cole rose slowly, turning toward the open doorway where the trembling butler stood clutching a tarnished brass candlestick tightly. She knew, deep within her experienced bones, that tonight would test every single investigative skill she had ever truly mastered.
created_at
"2026-05-29T10:04:16.987Z"
5/29/2026, 10:04:16 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3936
moderation_latency
(null)
generation_time
34005
tokens_prompt
46
tokens_completion
559
native_tokens_prompt
60
native_tokens_completion
3753
native_tokens_completion_images
(null)
native_tokens_reasoning
284
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
0.094125
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01APMDLTmkFkU4PE8Z57XZiu"
is_byok
false
latency
1161
model_permaslug
"anthropic/claude-4.8-opus-20260528"
provider_name
"Anthropic"
status
200
user_agent
"langchainjs-openai/1.0.0 ((node/v24.16.0; linux; x64))"
http_referer
(null)
request_id
"req-1780049056-maVGMfg4V2ZdjPLGsvMq"
session_id
(null)
api_type
"completions"
id
"gen-1780049056-F3APsTwlcZVNzxYZVtvO"
upstream_id
"msg_01APMDLTmkFkU4PE8Z57XZiu"
total_cost
0.094125
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
response_cache_source_id
(null)
Evaluation details
Result
Evaluator
Details
Meta Data
100.00%
Matches word count
n/a
neededClean
false
sentences
8
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20