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Run: 2026-05-29-01KSSK3484T1BZ1NZY46QHCAGY
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
29.0s
Cost:
$0.075975
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 fell heavily against the old manor windows as Detective Sarah Croft stepped across the marble entrance hall. A lifeless body lay sprawled beneath the grand staircase, surrounded by shattered glass and a slowly spreading pool of blood. The murdered victim, wealthy patriarch Edmund Blackwood, had hosted a dinner party for seven guests just hours before his death. Now those frightened guests waited nervously in the drawing room, each one harboring secrets that might explain this terrible crime. Sarah knelt beside the cold corpse, noting the strange silver dagger embedded deep within Edmund Blackwood's once proud beating chest. Outside, the violent storm intensified further, trapping everyone inside the isolated estate until the morning, with no escape from justice.
created_at
"2026-05-29T10:04:48.782Z"
5/29/2026, 10:04:48 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3554
moderation_latency
(null)
generation_time
28938
tokens_prompt
46
tokens_completion
480
native_tokens_prompt
60
native_tokens_completion
3027
native_tokens_completion_images
(null)
native_tokens_reasoning
274
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
0.075975
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01Xrm2sRRu5vPrvhaEJaxHij"
is_byok
false
latency
1046
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-1780049088-l6hUsur6W0ZFhaRWM3cx"
session_id
(null)
api_type
"completions"
id
"gen-1780049088-paHDUq4dccj8L5qdn7tk"
upstream_id
"msg_01Xrm2sRRu5vPrvhaEJaxHij"
total_cost
0.075975
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