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Run: 2026-05-29-01KSSK9X0FW1VM330GR347TSSQ
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
20.5s
Cost:
$0.052650
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 from her car into the October chill. Inside the grand foyer, a body lay sprawled across the cold marble floor, with crimson pooling slowly beneath the chandelier. The victim, wealthy industrialist Charles Pemberton, stared lifelessly upward, his expensive silk tie loosened and his pale fingers strangely curled. Around him gathered seven nervous guests, each clutching a secret, each watching Sarah approach with thinly veiled and growing dread. Thunder cracked overhead as she crouched beside him, noting the shattered wine glass glinting amid the scattered playing cards nearby. She rose slowly, her sharp gaze sweeping across the faces, searching each expression for guilt, fear, or carefully practiced innocence. Someone in this opulent room had committed murder tonight, and Sarah intended to unmask them before the storm finally passed.
created_at
"2026-05-29T10:08:30.742Z"
5/29/2026, 10:08:30 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3808
moderation_latency
(null)
generation_time
20461
tokens_prompt
46
tokens_completion
457
native_tokens_prompt
60
native_tokens_completion
2094
native_tokens_completion_images
(null)
native_tokens_reasoning
226
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
0.05265
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01J2jd3xF2YDNjKoGoDqWvqa"
is_byok
false
latency
920
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-1780049310-GgF4G0mVFKCw34hZYzxp"
session_id
(null)
api_type
"completions"
id
"gen-1780049310-JtgEeFzJPOF7sQxVwaTC"
upstream_id
"msg_01J2jd3xF2YDNjKoGoDqWvqa"
total_cost
0.05265
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
7
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20