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Run: 2026-05-29-01KSSJH7T7G7CAV2TQF935H2D6
Run Details
Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
29.2s
Cost:
$0.078800
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 marble entrance floor. A single body lay sprawled beneath the grand wooden staircase, surrounded by shattered glass and a widening pool of blood. The victim, wealthy industrialist Harold Vance, had hosted a lavish dinner party for twelve guests just three hours earlier tonight. Now each of them remained trapped inside, unaware that one among the small group had committed this brutal murder tonight. Sarah knelt beside the cold corpse, studying the strange wound while heavy rain drummed steadily on the roof above them. Outside, the storm raged even louder, sealing the manor completely, while inside, suspicion poisoned every whispered conversation between frightened guests.
created_at
"2026-05-29T09:55:02.609Z"
5/29/2026, 9:55:02 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3961
moderation_latency
(null)
generation_time
29082
tokens_prompt
46
tokens_completion
416
native_tokens_prompt
60
native_tokens_completion
3140
native_tokens_completion_images
(null)
native_tokens_reasoning
211
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
0.0788
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01XqQsyuwCEqFdCHjiq4S7Jw"
is_byok
false
latency
1043
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-1780048502-GO9D8NxQWehHoWTIuN6o"
session_id
(null)
api_type
"completions"
id
"gen-1780048502-YF0yeqv8fJsCH5hgi92f"
upstream_id
"msg_01XqQsyuwCEqFdCHjiq4S7Jw"
total_cost
0.0788
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