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Run: 2026-05-29-01KSSK9VJNF3NDPK71F620XVAB
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
23.9s
Cost:
$0.065000
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 windows of the old mansion, drowning out every sound except the wind's mournful howling. Detective Marlowe stepped slowly inside, removing his soaked hat while quietly studying the grand foyer with its flickering chandelier above. The lifeless body lay sprawled across the marble staircase, one arm reaching upward as though pleading for someone's desperate help. Around the cold corpse, five guests stood frozen, their pale faces betraying secrets that the storm could never wash away. Marlowe knelt down beside the lifeless victim, noting the thin blade buried deep within the chest, glinting under dim light. He glanced slowly upward, scanning each suspect carefully, knowing that one among them had committed this terrible, calculated, bloody crime.
created_at
"2026-05-29T10:08:29.28Z"
5/29/2026, 10:08:29 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3557
moderation_latency
(null)
generation_time
23517
tokens_prompt
46
tokens_completion
349
native_tokens_prompt
60
native_tokens_completion
2588
native_tokens_completion_images
(null)
native_tokens_reasoning
153
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
0.065
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01S8iv6PXW3W7v1HsBsasMYb"
is_byok
false
latency
1021
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-1780049309-4IIPYLPgwQ8ymTuNRqb0"
session_id
(null)
api_type
"completions"
id
"gen-1780049309-3n0vHFN62pAD09c22ow4"
upstream_id
"msg_01S8iv6PXW3W7v1HsBsasMYb"
total_cost
0.065
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