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Run: 2026-05-31-01KSYXAS8MBZNQ5DE9TYTS14CT
Run Details
Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
18.1s
Cost:
$0.045150
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 mansion windows as Detective Sarah Cole stepped slowly across the creaking wooden floor. A single lamp flickered weakly in the corner, casting long shadows that danced upon the blood-stained old Persian rug below. The body of the wealthy patriarch Edmund Blackwood lay sprawled near the cold fireplace, his glassy eyes staring upward forever. Outside, the thunder rumbled ominously while inside the gathered family members whispered nervously about who had committed this terrible deed. Sarah knelt beside the victim, noting the strange silver dagger embedded deeply within his chest, glinting in the dim light. She glanced upward toward the grand staircase where five suspects stood frozen, each harboring secrets that could prove utterly deadly.
created_at
"2026-05-31T11:39:57.601Z"
5/31/2026, 11:39:57 AM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3247
moderation_latency
147
generation_time
17929
tokens_prompt
46
tokens_completion
302
native_tokens_prompt
60
native_tokens_completion
1794
native_tokens_completion_images
(null)
native_tokens_reasoning
105
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
0.04515
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_01XgpV3h5aixf1GzuJfvQR2j"
is_byok
false
latency
1205
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-1780227597-Cl6wlFQHnB3qb6asl6yG"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780227597-OGB6QyInB01ruPGg40WF"
upstream_id
"msg_01XgpV3h5aixf1GzuJfvQR2j"
total_cost
0.04515
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