Run: 2026-05-31-01KSYXM4VPBQFFSAM4AM5XNB48

Run Details

Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 10 words each
Duration:
12.0s
Cost:
$0.027925
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 10 words. Please make sure that each sentence has the same length. Only return the opening itself.

Model response

AI
The cold rain fell hard against the mansion's tall windows. Detective Sarah Cole stepped slowly through the heavy front door. Inside, the air smelled of smoke, wine, and fresh blood. A man lay sprawled across the cold marble floor below. His eyes stared blankly toward the flickering chandelier above him. Three guests stood frozen near the grand staircase, watching silently. Nobody spoke a single word about what had happened here. Sarah knelt down beside the body and studied it carefully. A silver knife glinted just inches from his open hand. Someone in this room had committed murder tonight, she knew.
created_at"2026-05-31T11:45:04.387Z" 5/31/2026, 11:45:04 AM
model"anthropic/claude-4.8-opus-20260528"
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency3187
moderation_latency(null)
generation_time11930
tokens_prompt46
tokens_completion376
native_tokens_prompt60
native_tokens_completion1105
native_tokens_completion_images(null)
native_tokens_reasoning224
native_tokens_cached0
num_media_prompt(null)
num_input_audio_prompt(null)
num_media_completion0
num_search_results(null)
num_fetches(null)
web_search_engine(null)
origin"https://ncbench.com/"
is_byokfalse
finish_reason"stop"
native_finish_reason"end_turn"
service_tier"default"
usage0.027925
router(null)
provider_responses
0
endpoint_id"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id"msg_01XopYAsonqRgxQ8RW2XRu4r"
is_byokfalse
latency1041
model_permaslug"anthropic/claude-4.8-opus-20260528"
provider_name"Anthropic"
status200
user_agent"langchainjs-openai/1.0.0 ((node/v24.16.0; linux; x64))"
http_referer(null)
request_id"req-1780227904-Qd1cAoaJ1weeaU6qUWaE"
session_id(null)
preset_id(null)
api_type"completions"
id"gen-1780227904-D0kHskCt3NLPcAGvv73Y"
upstream_id"msg_01XopYAsonqRgxQ8RW2XRu4r"
total_cost0.027925
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic"
response_cache_source_id(null)

Evaluation details

Result Evaluator Details Meta Data
100.00% Matches word count n/a
neededCleanfalse
sentences10
wordCounts
010
110
210
310
410
510
610
710
810
910