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Run: 2026-06-01-01KT1G66PAC1N7J6ZJ10BKYBVF
Run Details
Model:
Claude Opus 4.8 (Reasoning, Low)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
31.6s
Cost:
$0.085300
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 heavily against the old manor windows as Detective Sarah Cole stepped through the creaking wooden front door. Inside the dim and silent hallway, a single chandelier flickered above the lifeless body sprawled across the cold marble floor. The wealthy old patriarch Edmund Blackwood lay motionless, his eyes wide open, staring blankly toward the grand spiral staircase nearby. Detective Cole knelt down beside him, noting the shattered glass and the dark crimson stain spreading slowly beneath his head. Upstairs, the frightened family members whispered nervously among themselves, each hiding dark secrets they desperately hoped would never be revealed.
created_at
"2026-06-01T11:47:59.311Z"
6/1/2026, 11:47:59 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3695
moderation_latency
(null)
generation_time
31602
tokens_prompt
46
tokens_completion
445
native_tokens_prompt
60
native_tokens_completion
3400
native_tokens_completion_images
(null)
native_tokens_reasoning
271
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
0.0853
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01RqUEmVYuHdDnRHzZiindL8"
is_byok
false
latency
1130
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-1780314479-mctPpmGN3iAZ56eScKss"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780314479-QgPKMXXH2ODMegyFEH5u"
upstream_id
"msg_01RqUEmVYuHdDnRHzZiindL8"
total_cost
0.0853
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
5
wordCounts
0
20
1
20
2
20
3
20
4
20