NC Bench
Overview
About
Tests
Categories
Models
Vendors
Compare
Run: 2026-05-31-01KSYXC3SMTYKJ25WFMPPB7JCF
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
23.9s
Cost:
$0.060575
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 rain fell hard against the manor windows as Detective Sarah Mills stepped carefully across the slick stone threshold tonight. Inside the grand foyer, a single chandelier flickered dimly above the body sprawled awkwardly upon the cold marble floor below. Mr. Harold Pennington, the wealthy owner of this grand estate, lay quite motionless with dark crimson blood pooling beneath him. Sarah crouched low beside the corpse, her gloved fingers searching gently for any clue the killer had carelessly left behind. A grandfather clock chimed midnight while five frightened guests gathered nervously inside the adjoining parlor, awaiting her difficult questions now. Each of them possessed both a motive and an opportunity, yet only one among them had truly committed the murder.
created_at
"2026-05-31T11:40:41.153Z"
5/31/2026, 11:40:41 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3912
moderation_latency
(null)
generation_time
23881
tokens_prompt
46
tokens_completion
317
native_tokens_prompt
60
native_tokens_completion
2411
native_tokens_completion_images
(null)
native_tokens_reasoning
123
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
0.060575
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01TNL9Pn8oFxnw9NstJsK5Yb"
is_byok
false
latency
1406
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-1780227641-AwuKQG07HDu0VNE4H9Vc"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227641-wkLRW1uaVHgJddfmywev"
upstream_id
"msg_01TNL9Pn8oFxnw9NstJsK5Yb"
total_cost
0.060575
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
6
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20