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Run: 2026-06-01-01KT1HY6ZA3R0ZG0FQD8X3XABF
Run Details
Model:
Claude Opus 4.8 (Reasoning, Low)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
17.1s
Cost:
$0.046900
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 mansion windows as Detective Sarah Cole stepped carefully across the cold muddy front lawn. Inside, the body of the wealthy patriarch Edward Hartwell lay sprawled beneath the grand staircase, dark blood pooling around him. Five anxious relatives huddled together inside the parlor, their faces pale, each one secretly hoping nobody suspected their own guilt. Sarah knelt beside the cold corpse, noting the strange silver letter opener buried deep within the old man's broken chest. Outside, the thunder rolled menacingly across the darkened sky while the killer watched silently from the shadows near the doorway.
created_at
"2026-06-01T12:18:34.607Z"
6/1/2026, 12:18:34 PM
model
"anthropic/claude-4.8-opus-20260528"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
3561
moderation_latency
(null)
generation_time
17056
tokens_prompt
46
tokens_completion
306
native_tokens_prompt
60
native_tokens_completion
1864
native_tokens_completion_images
(null)
native_tokens_reasoning
137
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
0.0469
router
(null)
provider_responses
0
endpoint_id
"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id
"msg_012s8XjbnCxhd6WGsWKpFPpR"
is_byok
false
latency
913
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-1780316314-ltqG6b2RsgkO5o8c1MHi"
session_id
(null)
preset_id
(null)
api_type
"completions"
id
"gen-1780316314-Ss6o1C900BOQa4yC590m"
upstream_id
"msg_012s8XjbnCxhd6WGsWKpFPpR"
total_cost
0.0469
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