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Run: 2026-04-24-01KQ0Q1N372M94YBZ99X4EQPD4
Run Details
Model:
GPT-5.5 (Reasoning, Low)
Test:
N-Length Sentences
Scenario:
Write sentences with 20 words each
Duration:
14.5s
Cost:
$0.029425
Provider:
OpenAI
Evaluation summary
Score
Evaluator
Details Link
95.08%
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 stitched silver threads across Blackthorn Manor's windows while Inspector Vale arrived late, carrying a telegram and troubled patience in silence. Inside, the grandfather clock had stopped at midnight, though every guest swore they had heard thirteen chimes from upstairs clearly. Lord Blackthorn lay beneath the portrait gallery's skylight, one hand clenched around a torn white glove stained with ink tonight. No blood marked his evening coat, only a dark crescent bruise blooming above his pearl collar like hidden moonrise there. Lady Miriam stood nearest, smelling faintly of violets, with rainwater shining on her unbuttoned satin shoes beside the body alone. The butler insisted the library doors were locked, yet the key rested inside Vale's empty teacup still warm from service. When lightning revealed muddy footprints crossing the Persian carpet, everyone looked down except the dead man's brother near the window. Vale opened his notebook, and somewhere behind the walls, a woman began laughing softly, then abruptly stopped as candles guttered.
created_at
"2026-04-24T21:41:30.349Z"
4/24/2026, 9:41:30 PM
model
"openai/gpt-5.5-20260423"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
13711
moderation_latency
(null)
generation_time
14366
tokens_prompt
46
tokens_completion
572
native_tokens_prompt
41
native_tokens_completion
974
native_tokens_completion_images
0
native_tokens_reasoning
766
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
0.029425
router
(null)
provider_responses
0
endpoint_id
"58e5b336-423e-430b-a2ab-8bc353f0c51b"
id
"resp_0a14c4eb510102290169ebe38a6b988195a74d4abdbf64db7e"
is_byok
false
latency
317
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-1777066890-1n0MnKR0F0BUtq5SVjUL"
session_id
(null)
api_type
"completions"
id
"gen-1777066890-DMH1SoU2pRqNSYarRri7"
upstream_id
"resp_0a14c4eb510102290169ebe38a6b988195a74d4abdbf64db7e"
total_cost
0.029425
cache_discount
(null)
upstream_inference_cost
0
provider_name
"OpenAI"
response_cache_source_id
(null)
Evaluation details
Result
Evaluator
Details
Meta Data
95.08%
Matches word count
n/a
neededClean
false
sentences
8
wordCounts
0
21
1
20
2
20
3
20
4
20
5
20
6
20
7
20