NC Bench
Overview
About
Tests
Models
Model
Claude Opus 4.5
Test
N-Length Sentences
Scenario
Write sentences with 20 words each
Run ID
2026-02-08-01KGYY1G87FGN807YGRFMXEXET
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 grandfather clock struck midnight as Detective Sarah Chen stepped into the abandoned mansion on Blackwood Hill last night. Rain pelted the broken windows while thunder rumbled ominously across the dark sky, creating an atmosphere of pure dread. A body lay sprawled across the marble floor, one hand reaching toward the locked door in frozen desperate terror. The victim was wealthy businessman Harold Crane, found by his terrified housekeeper who had heard strange noises around eleven. Blood pooled beneath his expensive silk shirt, and his eyes stared blankly at the crystal chandelier hanging far above. Sarah knelt beside the corpse, noting the unusual wound pattern that suggested this was no ordinary robbery gone terribly wrong. Her partner Detective Marcus Webb arrived moments later, shaking water from his coat as he surveyed the grim crime scene. No signs of forced entry anywhere in the house meant the killer either had a key or was invited inside. The housekeeper mentioned that Crane had been expecting an important visitor, but she never saw anyone actually enter the mansion. Sarah noticed a torn piece of expensive fabric clutched tightly in the dead man's rigid fist, perhaps from his attacker.
created_at
"2026-02-08T15:31:13.521426+00:00"
Sunday, February 8th, 2026 at 3:31:13 PM GMT+00:00
model
"anthropic/claude-4.5-opus-20251124"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1567
moderation_latency
163
generation_time
7088
tokens_prompt
35
tokens_completion
226
native_tokens_prompt
44
native_tokens_completion
257
native_tokens_completion_images
(null)
native_tokens_reasoning
0
native_tokens_cached
0
num_media_prompt
(null)
num_input_audio_prompt
(null)
num_media_completion
0
num_search_results
(null)
origin
"https://ncbench.com/"
is_byok
false
finish_reason
"stop"
native_finish_reason
"stop"
usage
0.006645
router
(null)
provider_responses
0
id
"2e1edca4-004e-4baa-9a6f-bdb9944617a8"
status
200
is_byok
false
latency
1567
endpoint_id
"de32581c-2e11-4f54-8d29-e8a6e19d3038"
provider_name
"Amazon Bedrock"
model_permaslug
"anthropic/claude-4.5-opus-20251124"
api_type
"completions"
id
"gen-1770564665-Dq5dyFmtkavp61PS6qpS"
upstream_id
"2e1edca4-004e-4baa-9a6f-bdb9944617a8"
total_cost
0.006645
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Amazon Bedrock"
Evaluation details
Result
Evaluator
Details
Meta Data
80.3265%
Matches word count
n/a
neededClean
false
sentences
10
wordCounts
0
19
1
19
2
19
3
19
4
19
5
20
6
20
7
20
8
20
9
20