Run: 2026-05-29-01KSSJF8KY8MT5N25M0GN8W5H3

Run Details

Model:
Claude Opus 4.8 (Reasoning)
Test:
N-Length Sentences
Scenario:
Write sentences with 5 words each
Duration:
5.2s
Cost:
$0.005550
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 mansion. Detective Cole stepped inside slowly. The body lay there still. Blood pooled across cold marble. Her eyes stared at nothing. A broken glass nearby glistened. Someone had silenced her forever. The grandfather clock kept ticking. Three guests waited upstairs nervously. Cole studied the silent room. Nothing here felt quite right. The killer remained among them.
created_at"2026-05-29T09:53:57.896Z" 5/29/2026, 9:53:57 AM
model"anthropic/claude-4.8-opus-20260528"
app_id182717
external_user(null)
streamedtrue
cancelledfalse
latency3368
moderation_latency(null)
generation_time5133
tokens_prompt46
tokens_completion142
native_tokens_prompt60
native_tokens_completion210
native_tokens_completion_images(null)
native_tokens_reasoning44
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"
usage0.00555
router(null)
provider_responses
0
endpoint_id"b0d3beaa-5ff7-4666-a749-b1bb2b14c916"
id"msg_01MKN1SrAs9Ph7uixE29FUhH"
is_byokfalse
latency1663
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-1780048437-hoPP9LHWZnfAyCkgi6pq"
session_id(null)
api_type"completions"
id"gen-1780048437-NV4V5GTLNiYr6TjAI7gm"
upstream_id"msg_01MKN1SrAs9Ph7uixE29FUhH"
total_cost0.00555
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
sentences12
wordCounts
05
15
25
35
45
55
65
75
85
95
105
115