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Run: 2026-02-24-01KJ8TPP0BBZ7PZCVDZAP61F0R
Run Details
Model:
Claude Sonnet 4.6 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
2m 38s
Cost:
$0.240513
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 20 words. Please make sure that each sentence has the same length. Only return the opening itself.
Model response
Messages
Meta
AI
The old lighthouse stood alone at the very edge of Harrow Bay, its single lantern slicing through cold November darkness. Detective Clara Marsh stepped out from her car just after midnight, the rain already soaking deeply through her wool coat. The emergency call had come in at eleven forty, a frantic voice reporting something terrible near the old keeper's cottage. She had not fully prepared herself for what waited just inside the lighthouse door, partly hidden beneath a dark blanket. The blanket had slipped, revealing a man who lay face down on the cold stone floor, one arm stretched out. His tailored dark evening suit and polished gold cufflinks told Marsh that this man had not expected to sleep here. There was absolutely no visible sign of blood, yet something about the cruel angle of his neck told Marsh everything. She crouched carefully down beside the body, pulling on gloves, and slowly studied the pale face turned toward the wall. She suddenly recognized him, even in death, even in that suffocating cold darkness, and felt her whole body go still. He was Victor Crane, a man that half the town truly despised and the other half quietly but deeply feared. Marsh stood up slowly, gazed at the rain hammering down against the single lighthouse window, and reached for her phone.
created_at
"2026-02-24T22:00:51.477Z"
2/24/2026, 10:00:51 PM
model
"anthropic/claude-4.6-sonnet-20260217"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
512
moderation_latency
180
generation_time
158258
tokens_prompt
46
tokens_completion
3435
native_tokens_prompt
61
native_tokens_completion
16022
native_tokens_completion_images
(null)
native_tokens_reasoning
3110
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
0.240513
router
(null)
provider_responses
0
endpoint_id
"6d408764-7dd7-4626-bb87-a6cc1589bc86"
id
"msg_0141FwwxpwYhUjDdvmRhVRay"
is_byok
false
latency
490
model_permaslug
"anthropic/claude-4.6-sonnet-20260217"
provider_name
"Anthropic"
status
200
api_type
"completions"
id
"gen-1771970451-09lsU9fKw4cTFw28HhxQ"
upstream_id
"msg_0141FwwxpwYhUjDdvmRhVRay"
total_cost
0.240513
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
Evaluation details
Result
Evaluator
Details
Meta Data
100.00%
Matches word count
n/a
neededClean
false
sentences
11
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20
8
20
9
20
10
20