NC Bench
Overview
About
Tests
Categories
Models
Vendors
Compare
Run: 2026-06-01-01KT1H70ES983W0H1E90TSN0J9
Run Details
Model:
Claude Opus 4.8 (Reasoning, Low)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
22.3s
Cost:
$0.061400
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 softly against the tall windows of Ravenswood Manor as Detective Sarah Holloway slowly stepped through the door. Inside the grand entrance foyer, a single bright chandelier flickered above the lifeless body sprawled across the cold marble floor. The victim, a very wealthy old man named Edmund Crane, clutched a torn letter tightly within his stiffened right hand. Sarah knelt down beside him, careful not to disturb anything, and studied the faint crimson stain blooming across his shirt. A tall grandfather clock chimed midnight loudly while the storm outside grew fiercer, rattling the ancient panes of every window. Somewhere upstairs, a loose floorboard creaked beneath unseen footsteps, reminding Sarah that the killer might still be inside this house.
created_at
"2026-06-01T12:05:54.269Z"
6/1/2026, 12:05:54 PM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3126
moderation_latency
(null)
generation_time
22252
tokens_prompt
46
tokens_completion
398
native_tokens_prompt
60
native_tokens_completion
2444
native_tokens_completion_images
(null)
native_tokens_reasoning
196
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
0.0614
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01BCaa5cJpTVLSJsNGwMfuVx"
is_byok
false
latency
1011
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-1780315554-UF8Y4nrJRXg0mF8fxmkJ"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780315554-3wFEAkazx0wa4kNcdvO6"
upstream_id
"msg_01BCaa5cJpTVLSJsNGwMfuVx"
total_cost
0.0614
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