NC Bench
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Run: 2026-02-17-01KHMQY25EXSF9V1JK7MGVXM62
Run Details
Model:
Claude Opus 4.5
Test:
Bad Writing Habits
Scenario:
Horror: alone in an eerie place at night
Duration:
53.1s
Cost:
$0.055740
Provider:
Anthropic
Model input
System
You are an expert novelist with a gift for vivid, immersive prose. You write in tight third-person limited point of view with a strong narrative voice. Your prose is clean, precise, and engaging — you favor strong verbs, concrete details, and natural-sounding dialogue. You will be given a story bible (codex) containing canonical details about characters, locations, items, and lore. Use these details to ground your writing in the established world. Stay consistent with the codex. Write only the prose of the scene. Do not include titles, chapter headings, markdown formatting, or any commentary before or after the scene.
User/Human
<codex> <character id="4412" name="Aurora Carter" aliases="Rory, Laila, Aurora, Carter, Malphora" pronouns="she/her" species="Human" storyRole="Protagonist"> <eyeColor>bright blue</eyeColor> <hair>straight shoulder-length black</hair> <height>5'6"</height> <age>25</age> <scar>small crescent-shaped scar on her left wrist from a childhood accident</scar> <description>Aurora, referred to by her friends as Rory, is cool-headed, intelligent, and known for quick out-of-the-box thinking.</description> <backstory>Born in Cardiff to an Irish barrister father (Brendan Carter) and Welsh teacher mother (Jennifer Carter née Ellis), Rory reluctantly pursued Pre-Law at Cardiff University. She fled to London at the behest of her childhood friend Eva after leaving an abusive ex named Evan. By day, Rory works part-time as a delivery person for Yu-Fei Cheung's Golden Empress restaurant. She lives in a flat above Silas' bar.</backstory> </character> <location id="861" name="The Fae Grove" aliases="Isolde's grove, Richmond grove, the Grove" realm="Earth (Fae-touched)"> <parkLocation>Richmond Park</parkLocation> <standingStones>ancient oak standing stones mark the boundary</standingStones> <timeBehavior>time moves differently — an hour inside can be minutes or days outside</timeBehavior> <flora>wildflowers bloom year-round</flora> <description>A hidden clearing that exists in a pocket between Earth and the Fae realm.</description> </location> <item id="2001" name="Heartstone Pendant" aliases="the pendant, Heartstone" type="Artifact" origin="Dymas"> <gemstoneColor>deep crimson</gemstoneColor> <chainMaterial>silver chain</chainMaterial> <size>roughly the size of a thumbnail</size> <behavior>pulses faintly with warmth when near a Hel portal</behavior> <glow>faint inner glow</glow> <description>Given to Aurora by an unknown benefactor.</description> </item> </codex> Write a fully fleshed out scene of at least 1000 words in the horror genre. A character is alone in a strange, isolated place at night. They came here for a reason, but something feels off from the moment they arrive. The wrongness builds slowly — sounds that shouldn't be there, things that move at the edge of vision, a growing certainty that they are not alone. Build tension through restraint, not through gore. Use the codex entries above as your world reference for the character and setting. Only include the prose of the scene without any markdown or commentary.
Model response
Messages
Meta
AI
The last light bled from the sky as Aurora stepped off the path and into the undergrowth. Richmond Park had emptied hours ago, the gates long since locked, but she knew the gap in the fence near the Pembroke Lodge car park—had used it twice before when Isolde summoned her after dark. Tonight, though, no summons had come. Tonight she'd come on her own. The Heartstone pendant lay warm against her collarbone, a steady pulse like a second heartbeat. It had been doing that for three days now. Faint at first, easy to dismiss as imagination or the radiator in her flat kicking on. But the warmth had grown persistent, insistent, and when she'd passed through Richmond on a deli
very
run that afternoon, the pendant had flared so hot she'd nearly crashed Yu-Fei's scooter into a parked van. Something was wrong at the grove. She needed to
know
what. The oak trees rose around her like
sentinels
, their branches stripped bare by November's teeth. Frost crunched beneath her trainers. She'd dressed for this—dark jeans, her warmest coat, a torch she kept clicking on and off because somehow the beam made the shadows worse, not better. Made them move. She left the torch off. The standing stones emerged from the darkness gradually, their shapes resolving from the general murk of the wood like figures stepping forward from a crowd. Ancient oaks, but not oaks anymore—petrified somehow, calcified into something that was neither wood nor stone but held the memory of both. Aurora had asked Isolde about them once. The fae woman had
smiled that knife
-edge smile of hers and said only that they remembered, and that was enough. Aurora stopped at the boundary. The grove looked wrong. She couldn't say why at first. The clearing beyond the standing stones was dark, yes, darker than it should have been with the moon rising fat and nearly full above the treeline. The wildflowers that b
loomed
year-round in Isolde's domain—she couldn't see them. Couldn't see much of anything past the first few feet beyond the boundary stones. But that wasn't what made her hesitate. What made her hesitate was the silence. The Fae Grove was never silent. Even in the depths of winter, even in the small hours when the boundary between worlds grew thin as tissue paper, there was always something. The whisper of grass that grew without wind. The distant, sourceless music that made her
think
of her grandmother's stories about the fair folk. The soft breathing of a place that was, in some fashion she didn't fully understand, alive. Now there was nothing. The silence was so complete it had
weight
, had texture. It pressed against her eardrums like deep water. The pendant pulsed. Warm. Warmer. Almost hot now, the crimson gemstone throwing a faint glow against the hollow of her throat. Aurora touched the silver chain, and her fingers came away damp. Not with sweat. With something thicker. In the dim light, it looked black. She wiped her hand on her jeans without looking at it. One step forward. Then another. The boundary stones
loomed
on either side of her, and she had the sudden, irrational certainty that they
were leaning
in. Bending toward her. Reaching. She crossed into the grove. The cold hit her first—a cold that had nothing to do with November, that sank through her coat and her jumper and her skin and settled somewhere in the marrow of her bones. Aurora's breath clouded in front of her face, thick and white, and in the strange half-light of the grove she could
see that it
wasn't dispersing
. It hung there, suspended, a ghost of exhalation that refused to fade. The wildflowers were dead. That was wrong. That was deeply, fundamentally wrong. She'd been here in the height of a July heatwave and seen snowdrops blooming alongside summer roses, bluebells pushing up through carpets of autumn leaves. Isolde's magic kept this place outside of time, outside of seasons. The flowers couldn't die here. But they had. They lay flat against the frozen ground, their petals blackened as if by fire, their stems collapsed and rotting. The smell hit her a moment later—sweet and cloying, the perfume of decay. Aurora pressed the back of her hand against her nose and breathed through her mouth. She should leave. She knew she should leave. But her feet carried her forward anyway, deeper into the clearing, toward the great oak that stood at its heart. The oak where Isolde held her court. The oak that was— Gone. Aurora stopped dead. The oak
was gone
. In its place stood a wound in the world—a ragged vertical tear in the fabric of the air itself, perhaps eight feet tall and three feet wide. Its edges
flickered
and writhed, and through the gap she could see... nothing. Not darkness. Nothing. An absence so complete her mind refused to process it, sliding off the sight like water off oil. The pendant blazed against her skin, hot enough now to leave a mark, and Aurora understood with sudden terrible clarity what that warmth had been warning her about. Not a Hel portal. Not exactly. But something adjacent to one, something that used the same terrible geometry, the same violation of the boundaries between worlds. Something had torn its way into the grove. Or out of it. A sound broke the silence. Quiet at first, so quiet she might have imagined it. A wet sound. A rhythmic sound. Like something breathing, but wrong—too many beats, too irregular, as if whatever made it had never learned the pattern of inhale and exhale and was merely approximating. Aurora turned
slowly
,
very
slowly
, toward the sound. Nothing. Just the dead flowers and the frozen ground and the standing stones at the boundary, silhouetted against the deeper dark of the woods beyond. But one of the stones had moved. She was certain of it. Absolutely certain. She'd entered between the two largest, the ones that flanked what passed for the grove's entrance, and they'd been perhaps ten feet apart. Now they were closer. Eight feet, maybe. Seven. Close enough that she'd have to turn sideways to slip between them on her way out. The wet breathing sound came again. Closer now. Behind her. Aurora did not turn around. Instead, she started walking. Steady, measured steps toward the boundary. Her heart slammed against her ribs so hard she could feel it in her throat, could hear the blood rushing in her ears. The pendant had gone cold—
suddenly
, shockingly cold, as if all its warmth had
been leached
away by proximity to something that should not exist. The stones were closer. Six feet apart now. Five. She could feel it behind her. Could feel the displacement of air as something massive moved through space that shouldn't have been able to contain it. Could smell it too, under the sweetness of the rotting flowers—a mineral smell, old and cold and deep, like the air at the bottom of a cave that had never
know
n sunlight. Don't run, she told herself. Don't run don't run don't run because if you run it will
know
you're prey and it will chase and you can't outrun it you
know
you can't— A hand touched the back of her neck. Cold. So cold. Fingers too long, too thin, with too many joints, tracing the bumps of her spine like a pianist exploring keys. The touch was almost gentle. Curious. The way a cat might examine a mouse before deciding whether to play or simply bite. Aurora stopped breathing. The fingers moved up, over the curve of her skull, into her hair. She could feel them against her scalp, probing, searching. Looking for something. The pendant lay dead and cold against her chest, offering no warmth, no warning, nothing. The fingers found her left ear. Traced its shell. Paused. The breathing behind her changed. Quickened. Excited. And then the fingers withdrew. Aurora didn't move. Didn't breathe. Didn't
think
. She stood
perfectly
still as the presence behind her receded—not walking, not moving the way anything with mass and
weight
should move. Simply becoming more distant, as if space itself
were stretching
to accommodate its departure. The wet breathing faded. The cold lifted, degree by degree. The standing stones were still there when she finally looked at them again, still impossibly close, but they'd stopped moving. She was alone. Aurora ran. She didn't remember crossing the boundary. Didn't remember the woods, the fence, the empty streets of Richmond in the small hours. Didn't remember the night bus or the walk from the stop to Silas's bar or the endless flights of stairs up to her flat. She remembered locking the door. Checking the windows. Sitting on the edge of her bed with e
very
light on and her phone in her hand, trying to remember how to breathe. She remembered looking at the pendant. The crimson gemstone
was cracked
down the center, a fracture that hadn't been there before. Through the crack, something dark pulsed—slow and steady and patient. Like a heartbeat. Like something waiting.
created_at
"2026-02-17T02:48:32.588872+00:00"
2/17/2026, 2:48:32 AM
model
"anthropic/claude-4.5-opus-20251124"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1338
moderation_latency
(null)
generation_time
53044
tokens_prompt
812
tokens_completion
2309
native_tokens_prompt
838
native_tokens_completion
2062
native_tokens_completion_images
(null)
native_tokens_reasoning
0
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
0.05574
router
(null)
provider_responses
0
id
"msg_01CSDnbeU9K11qihkfnsNw2y"
status
200
is_byok
false
latency
1338
endpoint_id
"be883404-eb42-4b2d-b6e4-c7daa3aa8d62"
provider_name
"Anthropic"
model_permaslug
"anthropic/claude-4.5-opus-20251124"
api_type
"completions"
id
"gen-1771296458-kSrNcEgFasHQ8lX99MSL"
upstream_id
"msg_01CSDnbeU9K11qihkfnsNw2y"
total_cost
0.05574
cache_discount
(null)
upstream_inference_cost
0
provider_name
"Anthropic"
Evaluation details
Result
Evaluator
Details
Meta Data
100.0000%
Adverbs in dialogue tags
Target: ≤10% dialogue tags with adverbs
totalTags
0
adverbTagCount
0
adverbTags
(empty)
67.2775%
AI-ism adverb frequency
Target: <1% AI-ism adverbs (57 tracked)
wordCount
1528
totalAiIsmAdverbs
5
found
0
adverb
"perfectly"
count
1
1
adverb
"slowly"
count
2
2
adverb
"suddenly"
count
1
3
adverb
"very"
count
1
highlights
0
"perfectly"
1
"slowly"
2
"suddenly"
3
"very"
100.0000%
AI-ism character names
Target: 0 AI-default names (17 tracked, −20% each)
codexExemptions
(empty)
found
(empty)
100.0000%
AI-ism location names
Target: 0 AI-default location names (33 tracked, −20% each)
codexExemptions
(empty)
found
(empty)
67.2775%
AI-ism word frequency
Target: <1% AI-ism words (140 tracked)
wordCount
1528
totalAiIsms
5
found
0
word
"sentinels"
count
1
1
word
"flickered"
count
1
2
word
"loomed"
count
1
3
word
"weight"
count
2
highlights
0
"sentinels"
1
"flickered"
2
"loomed"
3
"weight"
100.0000%
Cliche density
Target: ≤1 cliche(s) per 800-word window
totalCliches
0
maxInWindow
0
found
(empty)
highlights
(empty)
100.0000%
Emotion telling (show vs. tell)
Target: ≤3% sentences with emotion telling
emotionTells
0
narrationSentences
155
matches
(empty)
100.0000%
Filter word density
Target: ≤12% sentences with filter/hedge words
filterCount
2
hedgeCount
0
narrationSentences
155
filterMatches
0
"think"
1
"know"
hedgeMatches
(empty)
100.0000%
Overuse of "that" (subordinate clause padding)
Target: ≤10% sentences with "that" clauses
thatCount
2
totalSentences
155
matches
0
"smiled that knife"
1
"see that it"
100.0000%
Paragraph length variance
Target: CV ≥0.5 for paragraph word counts
totalParagraphs
55
mean
27.49
std
23.37
cv
0.85
sampleLengths
0
64
1
74
2
11
3
49
4
5
5
74
6
5
7
4
8
57
9
14
10
71
11
22
12
21
13
24
14
11
15
30
16
5
17
71
18
4
19
49
20
50
21
39
22
1
23
3
24
65
25
54
26
12
27
48
28
8
29
25
30
7
31
54
32
10
33
5
34
57
35
9
36
58
37
33
38
8
39
45
40
3
41
40
42
10
43
7
44
5
45
43
46
30
47
3
48
2
49
45
100.0000%
Passive voice overuse
Target: ≤5% passive sentences
passiveCount
3
totalSentences
155
matches
0
"was gone"
1
"been leached"
2
"was cracked"
100.0000%
Past progressive (was/were + -ing) overuse
Target: ≤10% past progressive verbs
pastProgressiveCount
3
totalVerbs
231
matches
0
"were leaning"
1
"wasn't dispersing"
2
"were stretching"
94.0000%
Purple prose (modifier overload)
Target: <4% adverbs, <2% -ly adverbs, no adj stacking
wordCount
1528
adjectiveStacks
1
stackExamples
0
"lay warm against her"
adverbCount
61
adverbRatio
0.03992146596858639
lyAdverbCount
20
lyAdverbRatio
0.013089005235602094
100.0000%
Repeated phrase echo
Target: ≤20% sentences with echoes (window: 2)
totalSentences
155
echoCount
0
echoWords
(empty)
100.0000%
Sentence length variance
Target: CV ≥0.4 for sentence word counts
totalSentences
155
mean
9.75
std
8.61
cv
0.883
sampleLengths
0
17
1
35
2
6
3
6
4
15
5
9
6
16
7
34
8
6
9
5
10
15
11
5
12
26
13
3
14
5
15
25
16
22
17
7
18
20
19
5
20
4
21
6
22
26
23
11
24
14
25
7
26
7
27
6
28
25
29
8
30
16
31
16
32
4
33
10
34
8
35
3
36
1
37
1
38
16
39
11
40
3
41
3
42
7
43
11
44
3
45
2
46
21
47
3
48
1
49
5
59.3548%
Sentence opener variety
Target: ≥60% unique sentence openers
consecutiveRepeats
18
diversityRatio
0.4258064516129032
totalSentences
155
uniqueOpeners
66
100.0000%
Dialogue tag variety (said vs. fancy)
Target: ≤30% fancy dialogue tags
totalTags
0
fancyCount
0
fancyTags
(empty)
93.4065%