Run: 2026-05-29-01KSSJMX2C3W8SGFNCNH02Q710

Run Details

Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 10 words each
Duration:
13.9s
Cost:
$0.032325
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 hammered against the old mansion's cracked windows. Detective Sarah Mills arrived just before the storm worsened considerably. Inside the study, a body lay sprawled across cold marble. Blood pooled slowly beneath the wealthy banker's lifeless still form. Five guests waited nervously in the dimly lit grand parlor. Each one clearly harbored secrets worth killing for, she suspected. The butler discovered the corpse barely one short hour ago. Thunder cracked loudly as the lights flickered then died completely. No one could leave until Sarah uncovered the brutal truth. Somewhere among them hid a clever and ruthless cold killer.
created_at"2026-05-29T09:57:02.679Z" 5/29/2026, 9:57:02 AM
model"anthropic/claude-4.8-opus-20260528"
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency3193
moderation_latency(null)
generation_time13899
tokens_prompt46
tokens_completion286
native_tokens_prompt60
native_tokens_completion1281
native_tokens_completion_images(null)
native_tokens_reasoning125
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"
usage0.032325
router(null)
provider_responses
0
endpoint_id"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id"msg_01WzBjJp2fRfF6mt3KghGsnp"
is_byokfalse
latency1098
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-1780048622-S0wl2ZaXVXHfrysKpGHB"
session_id(null)
api_type"completions"
id"gen-1780048622-zmXoL0tMRNeCbWp2kcV3"
upstream_id"msg_01WzBjJp2fRfF6mt3KghGsnp"
total_cost0.032325
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