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Run: 2026-04-24-01KQ0NZ12FB8NQ3VTYTCWVC54E
Run Details
Model:
GPT-5.5 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
18.4s
Cost:
$0.033955
Provider:
OpenAI
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
Rain needled the windows of Blackthorne Hall as Inspector Vale arrived, summoned by a telegram bearing no signature tonight whatsoever. Inside, the guests stood frozen around Lord Blackthorne, whose blood darkened the library carpet like spilled burgundy beneath their shoes. A silver letter opener jutted from his throat, pinning a lace cravat against skin already whitening under the yellow lamplight. No one claimed to hear a cry, though the storm had not yet broken above the moors that cold evening. Vale noticed muddy footprints crossing the hearth, then stopping precisely before the portrait of Blackthorne's first wife in mourning silks. Beside the corpse, a stopped pocket watch ticked once, impossibly, when Vale touched the shattered crystal with gloved fingertips lightly. Lady Blackthorne smiled faintly at that sound, and every candle in the room seemed to lean toward her pale face. Then the butler whispered that one guest was missing, and the locked conservatory smelled strongly of roses and old gunpowder.
created_at
"2026-04-24T21:22:35.733Z"
4/24/2026, 9:22:35 PM
model
"openai/gpt-5.5-20260423"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
17702
moderation_latency
(null)
generation_time
18053
tokens_prompt
46
tokens_completion
533
native_tokens_prompt
41
native_tokens_completion
1125
native_tokens_completion_images
0
native_tokens_reasoning
915
native_tokens_cached
0
num_media_prompt
(null)
num_input_audio_prompt
(null)
num_media_completion
0
num_search_results
(null)
num_fetches
(null)
web_search_engine
(null)
origin
"https://ncbench.com/"
is_byok
false
finish_reason
"stop"
native_finish_reason
"completed"
usage
0.033955
router
(null)
provider_responses
0
endpoint_id
"58e5b336-423e-430b-a2ab-8bc353f0c51b"
id
"resp_0cdea24c57da382f0169ebdf1bd8508190afb09bc5b85398c4"
is_byok
false
latency
257
model_permaslug
"openai/gpt-5.5-20260423"
provider_name
"OpenAI"
status
200
user_agent
"langchainjs-openai/1.0.0 ((node/v24.14.1; linux; x64))"
http_referer
(null)
request_id
"req-1777065755-IBF81lE2I9Hz0uCb4Zau"
session_id
(null)
api_type
"completions"
id
"gen-1777065755-ru7pqk8OKCCXJZu2sQIs"
upstream_id
"resp_0cdea24c57da382f0169ebdf1bd8508190afb09bc5b85398c4"
total_cost
0.033955
cache_discount
(null)
upstream_inference_cost
0
provider_name
"OpenAI"
response_cache_source_id
(null)
Evaluation details
Result
Evaluator
Details
Meta Data
100.00%
Matches word count
n/a
neededClean
false
sentences
8
wordCounts
0
20
1
20
2
20
3
20
4
20
5
20
6
20
7
20