Model

Claude Opus 4.6

Test

N-Length Sentences

Scenario

Write sentences with 10 words each

Run ID

2026-02-08-01KGYZKJJA67ZTZ141YPYVXK68

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 old mansion stood silent against the dark winter sky. Detective Sarah Chen arrived just as the clock struck twelve. She stepped carefully over the threshold into the grand foyer. A body lay crumpled at the base of the stairs. The victim wore an expensive suit stained deep with blood. His eyes stared blankly at the crystal chandelier hanging above. No one had heard the scream that cold December night. The butler stood trembling near the doorway to the parlor. He claimed to have discovered the body only minutes before. Sarah knelt beside the dead man and studied his face. She recognized him immediately as the wealthy industrialist Richard Blackwood. His wife had reported him missing just three days ago. Now here he was lying broken in his own home. A single red rose had been placed upon his chest. Sarah knew this killer had left a very deliberate message. She pulled on her gloves and began to examine him. There were bruises on his neck shaped just like fingers. The front door had been locked from the inside completely. Every window on the ground floor remained shut and latched. Someone in this house tonight was hiding a terrible secret.
created_at"2026-02-08T15:58:35.198073+00:00" Sunday, February 8th, 2026 at 3:58:35 PM GMT+00:00
model"anthropic/claude-4.6-opus-20260205" 
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency1469
moderation_latency(null)
generation_time8089
tokens_prompt35
tokens_completion231
native_tokens_prompt44
native_tokens_completion262
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" 
usage0.00677
router(null)
provider_responses
0
id"msg_01My3DZDrqkFGK58cZ3HBFGC" 
status200
is_byokfalse
latency1469
endpoint_id"c926c048-563e-44b0-8434-95965bee924c" 
provider_name"Anthropic" 
model_permaslug"anthropic/claude-4.6-opus-20260205" 
api_type"completions" 
id"gen-1770566306-ipsw9z7OV0JaGJetbAXy" 
upstream_id"msg_01My3DZDrqkFGK58cZ3HBFGC" 
total_cost0.00677
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic" 

Evaluation details

Result Evaluator Details Meta Data
100.0000% Matches word count n/a
neededCleanfalse
sentences20
wordCounts
010
110
210
310
410
510
610
710
810
910
1010
1110
1210
1310
1410
1510
1610
1710
1810
1910