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Run: 2026-05-31-01KSYX8107A6EFJTHVBQXAZDKR
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
32.0s
Cost:
$0.087800
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 cold rain hammered against the old mansion windows as Detective Sarah Cole stepped through the heavy oak front door. Inside, the lifeless body of wealthy businessman Charles Whitmore lay sprawled across the library floor near the cold marble fireplace. Dark blood pooled slowly beneath his head, staining the expensive Persian rug that had once cost him a small fortune. Sarah slowly knelt beside the corpse, careful not to disturb anything, and studied the strange wound on his pale neck. Whoever had killed poor Charles Whitmore did it quickly, silently, and with the precision of a truly experienced professional killer. Outside the violent storm raged even louder now, and somewhere in the vast house a frightened guest began to scream.
created_at
"2026-05-31T11:38:27.431Z"
5/31/2026, 11:38:27 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3577
moderation_latency
(null)
generation_time
31734
tokens_prompt
46
tokens_completion
475
native_tokens_prompt
60
native_tokens_completion
3500
native_tokens_completion_images
(null)
native_tokens_reasoning
289
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
0.0878
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01Wmu54xFBWA1cppX41pqt21"
is_byok
false
latency
1013
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-1780227507-QqoilQ90WpOU6foH49Lp"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227507-L2iMiTcaFYhim1vChxzl"
upstream_id
"msg_01Wmu54xFBWA1cppX41pqt21"
total_cost
0.0878
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