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Run: 2026-06-01-01KT1G1QX1P6MMWD1W83TNZ1E7
Run Details
Model:
Claude Opus 4.8 (Reasoning, Low)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
22.3s
Cost:
$0.055225
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 hammered against the old manor windows as Detective Sarah Cole stepped carefully across the cold polished marble floor. A body lay sprawled beneath the grand staircase, one pale hand reaching toward a shattered glass of expensive red wine. The victim, wealthy industrialist Charles Hartwell, had invited six guests tonight, and now one of them was clearly a murderer. Sarah knelt beside the cooling corpse, studying the angle of the wound while ignoring the nervous chatter from the parlor. Outside, thunder rolled across the darkened evening sky, and the only road leading away had flooded completely an hour earlier. No one could leave the isolated estate tonight, and Sarah intended to find the killer before sunrise finally broke through.
created_at
"2026-06-01T11:45:33.095Z"
6/1/2026, 11:45:33 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
4857
moderation_latency
(null)
generation_time
21551
tokens_prompt
46
tokens_completion
367
native_tokens_prompt
60
native_tokens_completion
2197
native_tokens_completion_images
(null)
native_tokens_reasoning
179
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
0.055225
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01KVYGwAEWSXqjvJWtpMLvzp"
is_byok
false
latency
2125
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-1780314333-fJMtwOfQHqjR9cXEux7l"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780314333-GlYEssAfOP7GyZrbMOHB"
upstream_id
"msg_01KVYGwAEWSXqjvJWtpMLvzp"
total_cost
0.055225
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