Model

Claude Opus 4.5

Test

N-Length Sentences

Scenario

Write sentences with 5 words each

Run ID

2026-02-08-01KGYYXXM3AKRWG82ZNP0MXJYM

Model input

User/Human
Please write the opening scene of a murder mystery where each sentence has exactly 5 words. Please make sure that each sentence has the same length. Only return the opening itself.

Model response

AI
The mansion stood in darkness. Rain pelted the old windows. Detective Harris approached the door. Her badge felt unusually heavy. Something terrible had happened here. A butler answered her knock. His face showed visible distress. "She's in the library, ma'am." Blood stained his white gloves. Harris noticed but said nothing. The library smelled like copper. Countess Morrison lay quite still. A knife pierced her chest. Her eyes stared at nothing. Pearls scattered across the floor. "Who discovered the body first?" Harris pulled out her notebook. The butler cleared his throat. "I did, around midnight, ma'am." His hands trembled quite visibly. Three suspects waited in chairs. Each one avoided eye contact. The widow's nephew looked pale. Her business partner seemed nervous. The young maid wept softly. Harris studied the crime scene. The window was slightly open. Muddy footprints marked the carpet. Someone had struggled here violently. The truth would emerge eventually.
created_at"2026-02-08T15:46:45.449462+00:00" Sunday, February 8th, 2026 at 3:46:45 PM GMT+00:00
model"anthropic/claude-4.5-opus-20251124" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1732
moderation_latency(null)
generation_time7874
tokens_prompt35
tokens_completion200
native_tokens_prompt44
native_tokens_completion222
native_tokens_completion_images(null)
native_tokens_reasoning0
native_tokens_cached0
num_media_prompt(null)
num_input_audio_prompt(null)
num_media_completion0
num_search_results(null)
origin"https://ncbench.com/" 
is_byokfalse
finish_reason"stop" 
native_finish_reason"stop" 
usage0.00577
router(null)
provider_responses
0
id"msg_01Kj28uexYY9RJGna8aXzzuG" 
status200
is_byokfalse
latency1727
endpoint_id"be883404-eb42-4b2d-b6e4-c7daa3aa8d62" 
provider_name"Anthropic" 
model_permaslug"anthropic/claude-4.5-opus-20251124" 
api_type"completions" 
id"gen-1770565596-nWvbqmW5QSavZbpJZ5Gz" 
upstream_id"msg_01Kj28uexYY9RJGna8aXzzuG" 
total_cost0.00577
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic" 

Evaluation details

Result Evaluator Details Meta Data
88.8889% Matches word count n/a
neededCleanfalse
sentences27
wordCounts
05
15
25
35
45
55
65
710
85
95
105
115
125
135
1410
155
1610
175
185
195
205
215
225
235
245
255
265