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Run: 2026-05-31-01KSYX8107H6E02M7NTW6HM4W1
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
29.7s
Cost:
$0.081750
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 manor windows as Detective Sarah Morgan stepped carefully across the creaking wooden floor. A single lifeless body lay sprawled before the grand fireplace, blood pooling slowly beneath the cold form of Lord Ashworth. His wide eyes stared blankly toward the high ceiling, frozen forever in an expression of pure, unmistakable terror and disbelief. Sarah crouched down beside the victim, carefully noting the silver letter opener buried deep within his chest, glinting in firelight. Behind her, the six remaining guests huddled together in nervous silence, each harboring secrets that might explain this brutal crime. Outside, the violent storm raged even louder, trapping everyone inside the isolated old estate until morning brought answers and justice.
created_at
"2026-05-31T11:38:27.437Z"
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
3670
moderation_latency
(null)
generation_time
29079
tokens_prompt
46
tokens_completion
407
native_tokens_prompt
60
native_tokens_completion
3258
native_tokens_completion_images
(null)
native_tokens_reasoning
209
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
0.08175
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_013qn7Rz73bY4ZkYoyUq3Sro"
is_byok
false
latency
1089
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-1780227507-35gxWoO5jPpEpURsUOoK"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227507-edmtU2Azq6tS6oCeC1co"
upstream_id
"msg_013qn7Rz73bY4ZkYoyUq3Sro"
total_cost
0.08175
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