Run: 2026-05-31-01KSYXB8ZBWR5H0B5RF5BS8XES

Run Details

Model:
Claude Opus 4.8 (Reasoning, High)
Test:
N-Length Sentences
Scenario:
Write sentences with 5 words each
Duration:
7.4s
Cost:
$0.006475
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 5 words. Please make sure that each sentence has the same length. Only return the opening itself.

Model response

AI
Rain hammered the old window. Detective Cole arrived past midnight. The mansion loomed in darkness. Inside, the body lay still. Blood pooled beneath the chandelier. The victim wore expensive jewelry. Her eyes stared at nothing. Someone had silenced her forever. Cole studied the lifeless room. Three guests waited downstairs nervously. Each one carried dark secrets. The killer remained among them. Cole removed his wet coat. Tonight, the truth would surface. Nobody would leave this house.
created_at"2026-05-31T11:40:13.688Z" 5/31/2026, 11:40:13 AM
model"anthropic/claude-4.8-opus-20260528"
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency5399
moderation_latency(null)
generation_time7313
tokens_prompt46
tokens_completion168
native_tokens_prompt60
native_tokens_completion247
native_tokens_completion_images(null)
native_tokens_reasoning45
native_tokens_cached0
num_media_prompt(null)
num_input_audio_prompt(null)
num_media_completion0
num_search_results(null)
num_fetches(null)
web_search_engine(null)
origin"https://ncbench.com/"
is_byokfalse
finish_reason"stop"
native_finish_reason"end_turn"
service_tier"default"
usage0.006475
router(null)
provider_responses
0
endpoint_id"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id"msg_01X5ZRMpZQrAnvwy4Rcjsrn1"
is_byokfalse
latency3720
model_permaslug"anthropic/claude-4.8-opus-20260528"
provider_name"Anthropic"
status200
user_agent"langchainjs-openai/1.0.0 ((node/v24.16.0; linux; x64))"
http_referer(null)
request_id"req-1780227613-ZRELYkNS11Yadw7vCTJn"
session_id(null)
preset_id(null)
api_type"completions"
id"gen-1780227613-ucAZyCTSx5hnb5hW6sAu"
upstream_id"msg_01X5ZRMpZQrAnvwy4Rcjsrn1"
total_cost0.006475
cache_discount(null)
upstream_inference_cost0
provider_name"Anthropic"
response_cache_source_id(null)

Evaluation details

Result Evaluator Details Meta Data
100.00% Matches word count n/a
neededCleanfalse
sentences15
wordCounts
05
15
25
35
45
55
65
75
85
95
105
115
125
135
145