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Run: 2026-05-31-01KSYXJA152HC95XGZPZTV8HA3
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
28.8s
Cost:
$0.073475
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 carefully across the muddy gravel driveway. Inside the grand foyer, a single body lay sprawled beneath the crystal chandelier, blood pooling slowly across cold marble tiles. Five frightened guests gathered nervously inside the candlelit parlor, each one wearing a mask of shock concealing their terrible secrets. Sarah knelt beside the victim, recognizing the famous millionaire whose vast fortune had attracted enemies from every corner of society. A single jeweled letter opener protruded from his chest, glinting beneath the lights like an accusation no one could ignore. Outside, thunder rolled across the darkened evening sky while Sarah slowly realized the killer was still somewhere inside this house.
created_at
"2026-05-31T11:44:04.146Z"
5/31/2026, 11:44:04 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4890
moderation_latency
(null)
generation_time
28713
tokens_prompt
46
tokens_completion
564
native_tokens_prompt
60
native_tokens_completion
2927
native_tokens_completion_images
(null)
native_tokens_reasoning
365
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
0.073475
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01UB7MfUCHTaSf8SShyaLBUR"
is_byok
false
latency
2377
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-1780227844-WfPzXGLPVafrq63YXO8Q"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227844-JdjNQsNXN6fRJ5jb4Q6n"
upstream_id
"msg_01UB7MfUCHTaSf8SShyaLBUR"
total_cost
0.073475
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