NC Bench
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Run: 2026-02-17-01KHMQKD3F3HNX3HQ5C7VGX04N
Run Details
Model:
Claude Opus 4.6
Test:
Bad Writing Habits
Scenario:
Horror: alone in an eerie place at night
Duration:
1m 18s
Cost:
$0.075220
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 train from Waterloo had deposited Rory at Richmond with seven minutes to spare before midnight, and she'd walked the rest of the way in the dark because she didn't trust herself to explain to a cab driver why she needed to be let out at the Isabella Plantation gate at this hour. The park
was closed
, of course. It had
been closed
since sunset. She climbed the fence where the iron railings dipped near the Petersham Road entrance, catching the hem of her jacket on a finial and tearing it as she dropped to the other side. The sound of the fabric ripping was louder than it should have been. E
very
thing was louder than it should have been. She stood in the wet grass and waited for her eyes to adjust. The text had come from Eva's phone at half past nine. Three words: *The Grove. Tonight.* No follow-up. No context. Rory had called back four times and gotten voicemail each time — Eva's cheerful,
slightly
breathless recording, the one she'd made two years ago after too many ciders, the one that still ended with her laughing at something Rory couldn't remember. Each time the message played, Rory's stomach had tightened a little more, until by the fourth call she was already pulling on her trainers and zipping her jacket and leaving the flat above Silas's bar without locking the door behind her. Now she was here, in the black expanse of Richmond Park, and the Heartstone pendant was warm against her sternum. She touched it through her shirt — a reflex, like pressing a tongue to a sore tooth. The crimson gem had been doing this for three days now, pulsing with a faint heat she could feel even through fabric, and she'd been ignoring it the way she ignored most things she didn't want to understand. But here, in the dark, with the park stretched out around her like a held breath, ignoring it felt less like pragmatism and more like cowardice. She followed the path she knew by memory. Past the pond, where the water lay flat and dark as spilled ink. Through the avenue of chestnuts, their bare branches interlocking overhead like the ribcage of something enormous. The moon was behind clouds and offered nothing. She used the torch on her phone sparingly, in quick sweeps, because the battery was at nineteen percent and because e
very
time she turned it on, the light
seemed to
stop shorter than it should have, as though the darkness ahead of her was denser, more solid, more reluctant to be pushed aside. She heard the deer before she saw them. A rustle in the bracken to her left, and then the heavy, deliberate sound of several large bodies moving away from her through the undergrowth. Red deer. Richmond was full of them. But they
were moving
in the wrong direction — away from the center of the park, toward the perimeter, toward the roads and the fences and the human noise they normally avoided. She watched their shapes pass between the trees, dark against dark, their antlers catching some faint ambient glow she couldn't source. They moved
quickly
. They moved like things that
were leaving
. The Heartstone pulsed. Warmth bloomed against her chest and faded, bloomed and faded, and Rory pressed her palm flat against it and kept walking. The standing stones came into view ten minutes later, though she couldn't have said exactly when she first noticed them. They didn't appear so much as accumulate — a thickening of shadow here, a too-regular shape there, until she
was standing
at the edge of the ring and the ancient oaks rose around her like dark pillars, their bark so weathered and
grooved that it
looked like petrified cloth. Wildflowers grew between them even now, even in November, small white and violet blooms that
seemed to
generate their own faint luminescence. She'd asked Isolde about that once. The fae woman had smiled in that unsettling way of hers and said the flowers didn't know what month it was. Rory stepped between two of the oaks and into the Grove. The air changed immediately. It was warmer on this side — not much, just enough to notice, like stepping into a room where someone had recently been sitting. The ground was soft. The wildflowers were thicker here, and their glow was stronger, enough that she could see the clearing in a pale wash of blue-white light. The grass was undisturbed. No one was here. "Eva?" she said, and her voice sounded wrong. Not wrong, exactly. Flat. The word left her mouth and went nowhere. In a normal clearing, even at night, sound would carry — bounce off trees, scatter into the sky, find its way to the ears of whatever small creatures
were hiding
in the undergrowth. Here, her voice traveled about six feet and stopped, as though it had hit something solid. The silence that followed wasn't empty. It was full. It was the silence of a room with someone in it who
was choosing
not to speak. Rory turned in a slow circle. The oaks stood at the perimeter of the clearing, evenly spaced, their canopy forming an unbroken ceiling overhead. Between them, beyond the boundary of the Grove, the park should have been visible — trees, paths, the distant amber smear of London's light pollution. But it wasn't. The spaces between the oaks were dark. Not nighttime dark. Not shadow dark. The kind of dark that looked like it had texture, like it would feel like something if she reached into it. She didn't reach into it. "Eva, if you're here, this isn't funny." The flatness swallowed her words again. She pulled out her phone. No signal. The battery read eleven percent now, though it had
been nineteen
only minutes ago. The clock on the screen said 12:07. She'd entered the park at midnight. She'd walked for at least twenty minutes. The math refused to work, and she let it go, because time in the Grove had never been reliable and thinking about it too hard was a door she didn't want to open tonight. She became aware of the sound gradually. It was underneath e
very
thing — underneath the nothing, underneath the suffocating quiet. A low, rhythmic vibration that she felt in the bones of her feet before she heard it with her ears. Not a hum, exactly. More like breathing. Slow, deep, steady breathing, as though the ground itself were drawing air and releasing it, and she
was standing
on the chest of something impossibly large. The Heartstone flared. Not the gentle pulse she'd grown accustomed to — this was a sharp, sudden burn, like a coal pressed against her skin, and she gasped and yanked the pendant out from under her shirt by its silver chain. The crimson gem was alight. Its inner glow, normally so faint she had to cup it in her hands and squint to see it, was now bright enough to cast her fingers in red, bright enough to throw her shadow behind her in a long, jagged streak. She looked at her shadow. Her shadow looked wrong. She
was standing
still. She was certain she
was standing
still. But the shadow on the grass behind her
was moving
— not in the way shadows moved when a light source shifted, not the gentle sway of a cast shape responding to the motion of the body that threw it. This was independent movement. Subtle, but unmistakable. The shadow's edges rippled and rearranged, as though something beneath the surface of it
were adjusting
its position. The head of the shadow turned,
slowly
, a degree or two to the left, while Rory's own head remained fixed. She stopped breathing. The shadow stopped moving. She stared at it for five seconds, ten seconds, fifteen. Nothing. Just a shadow. Just her shadow, thrown by the red glow of the Heartstone, motionless on the November grass. She exhaled. She told herself she'd imagined it. She
was scared
, and she was tired, and her brain
was filling
the silence with patterns that weren't there, the way brains did when— The breathing sound changed. It was still rhythmic, still deep, still coming from below and e
very
where at once. But it was faster now. Not much. Just enough to notice. As though whatever
was producing
it had also been holding its breath, and had just released it, and was now settling into a new rhythm that was
slightly
, incrementally more urgent. Rory became aware — with the specific,
crystalline
clarity that came right before
panic — that she
could no longer see the spaces between the standing oaks. The darkness that had filled those gaps had thickened, had advanced, had crept inward while she'd been watching her shadow, and now it pressed against the oaks like water against a dam. The wildflowers at the perimeter of the clearing had gone dark. Their bioluminescence simply wasn't there anymore, as though something had placed a hand over each one and smothered the light. The remaining glow came only from the flowers at the center of the Grove, the ones closest to where she stood, and their light was dimmer now,
wavering
, uncertain. And from the Heartstone, which blazed against her palm like a small red star. She heard the cracking sound from her right. She snapped her head toward it. One of the standing oaks — the largest, the one she'd always used to orient herself when she entered the Grove — was moving. Not falling. Not bending. Moving. The deep grooves in its bark
were rearranging
themselves with slow, grinding deliberation, the petrified cloth of its surface folding and unfolding, and in the shifting patterns of its grain she saw — or thought she saw, or
was terrified
that she saw — the suggestion of a face. Not a human face. Something longer. Something with too many planes and angles, something that
was trying
to resolve itself into an expression she could read and not quite managing. She took a step backward. Her heel found soft earth. The breathing beneath her feet quickened again. The other oaks
were doing
it now. E
very
one of them, all the way around the clearing, the slow grinding rearrangement of their surfaces, the sense of vast attention turning toward a single point. Toward her. The face-shapes in the bark were all different. Some were almost recognizable — the long, severe lines of something fae, the hollow suggestion of eyes, the dark groove that might have been a mouth. Others were less coherent, more abstract, just the raw impression of *watching* rendered in wood and shadow. The Heartstone burned. The pendant swung on its chain, and Rory realized her hand
was shaking
. From somewhere beyond the ring of oaks — from inside the dark, from the place that was no longer the park and might never have been the park — something called her name. Not Eva's voice. Not anyone's voice. It was her name shaped from the sound of branches breaking, from the groan of old wood, from the exhalation of the breathing ground. *Aurora.* Not Rory. Not the name her friends used. Her full name, spoken with the care of someone who had learned it recently and wanted to get it right. She ran. She didn't choose a direction. She chose the gap between two oaks where the darkness looked thinnest, where she thought — hoped — prayed — the park still existed on the other side, and she threw herself at it. The wildflowers crunched under her trainers. The air thickened around her like cold water. The Heartstone screamed red light against her chest. She hit the boundary of the Grove and for one terrible, elongated moment she felt resistance — not physical, not a wall, but a reluctance, a vast and patient unwillingness to let her go, like pulling free from a hand that wasn't gripping but simply hadn't decided to open. Then she was through, and she
was running
across wet grass in the dark, and behind her the Grove was silent. She didn't stop until she reached the fence. She climbed it badly, cutting her left wrist on the finial — a bright line of pain across the old crescent scar she'd carried since childhood. She dropped to the pavement on the other side and pressed her back against the railings and looked at her phone. The screen read 12:09. Two minutes. She'd been in there for two minutes. The Heartstone cooled
slowly
against her chest, its glow fading to a faint ember, then to nothing. Rory sat on the wet pavement and listened to the sound of distant traffic and the normal, uncomplicated silence of a city at night, and she did not call Eva again, and she did not go back to the Grove, and she did not look at her shadow for a
very
long time.
created_at
"2026-02-17T02:43:08.289656+00:00"
2/17/2026, 2:43:08 AM
model
"anthropic/claude-4.6-opus-20260205"
app_id
182717
external_user
(null)
streamed
true
cancelled
false
latency
1416
moderation_latency
(null)
generation_time
77988
tokens_prompt
812
tokens_completion
3140
native_tokens_prompt
839
native_tokens_completion
2841
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
0.07522
router
(null)
provider_responses
0
id
"msg_01NgtRy7qg6GjDZvYTmsjaF9"
status
200
is_byok
false
latency
1416
endpoint_id
"c926c048-563e-44b0-8434-95965bee924c"
provider_name
"Anthropic"
model_permaslug
"anthropic/claude-4.6-opus-20260205"
api_type
"completions"
id
"gen-1771296109-IFZz5jp9jf4LdHRsUdyZ"
upstream_id
"msg_01NgtRy7qg6GjDZvYTmsjaF9"
total_cost
0.07522
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
1
adverbTagCount
0
adverbTags
(empty)
71.9626%
AI-ism adverb frequency
Target: <1% AI-ism adverbs (57 tracked)
wordCount
2140
totalAiIsmAdverbs
6
found
0
adverb
"quickly"
count
1
1
adverb
"slightly"
count
2
2
adverb
"slowly"
count
2
3
adverb
"very"
count
1
highlights
0
"quickly"
1
"slightly"
2
"slowly"
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)
90.6542%
AI-ism word frequency
Target: <1% AI-ism words (140 tracked)
wordCount
2140
totalAiIsms
2
found
0
word
"crystalline"
count
1
1
word
"wavering"
count
1
highlights
0
"crystalline"
1
"wavering"
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
2
narrationSentences
154
matches
0
"was scared"
1
"was terrified"
100.0000%
Filter word density
Target: ≤12% sentences with filter/hedge words
filterCount
0
hedgeCount
2
narrationSentences
154
filterMatches
(empty)
hedgeMatches
0
"seemed to"
100.0000%
Overuse of "that" (subordinate clause padding)
Target: ≤10% sentences with "that" clauses
thatCount
3
totalSentences
155
matches
0
"grooved that it"
1
"panic — that she"
2
"terrified that she"
100.0000%
Paragraph length variance
Target: CV ≥0.5 for paragraph word counts
totalParagraphs
43
mean
50.23
std
41.12
cv
0.818
sampleLengths
0
120
1
13
2
102
3
20
4
81
5
98
6
103
7
24
8
118
9
11
10
64
11
8
12
87
13
86
14
5
15
7
16
81
17
7
18
65
19
88
20
5
21
4
22
96
23
3
24
4
25
62
26
4
27
56
28
119
29
14
30
8
31
114
32
17
33
87
34
16
35
33
36
59
37
2
38
110
39
21
40
68
41
17
42
53
100.0000%
Passive voice overuse
Target: ≤5% passive sentences
passiveCount
4
totalSentences
154
matches
0
"was closed"
1
"been closed"
2
"been nineteen"
3
"was terrified"
100.0000%
Past progressive (was/were + -ing) overuse
Target: ≤10% past progressive verbs
pastProgressiveCount
18
totalVerbs
338
matches
0
"were moving"
1
"were leaving"
2
"was standing"
3
"were hiding"
4
"was choosing"
5
"were drawing was standing"
6
"was standing"
7
"was standing"
8
"was moving "
9
"were adjusting"
10
"was filling"
11
"was producing"
12
"were rearranging"
13
"was trying"
14
"were doing"
15
"was shaking"
16
"was running"
90.8316%
Purple prose (modifier overload)
Target: <4% adverbs, <2% -ly adverbs, no adj stacking
wordCount
2132
adjectiveStacks
1
stackExamples
0
"Slow, deep, steady breathing,"
adverbCount
93
adverbRatio
0.04362101313320826
lyAdverbCount
23
lyAdverbRatio
0.010787992495309569
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
13.94
std
12.89
cv
0.925
sampleLengths
0
54
1
6
2
6
3
33
4
13
5
8
6
13
7
11
8
4
9
3
10
2
11
41
12
41
13
20
14
17
15
38
16
26
17
8
18
13
19
16
20
8
21
53
22
8
23
25
24
2
25
5
26
32
27
21
28
3
29
7
30
3
31
21
32
20
33
49
34
22
35
6
36
21
37
11
38
4
39
24
40
4
41
24
42
4
43
4
44
8
45
3
46
1
47
8
48
33
49
16
33.1183%
Sentence opener variety
Target: ≥60% unique sentence openers
consecutiveRepeats
27
diversityRatio
0.3032258064516129
totalSentences
155
uniqueOpeners
47
100.0000%
Dialogue tag variety (said vs. fancy)
Target: ≤30% fancy dialogue tags
totalTags
1
fancyCount
0
fancyTags
(empty)
93.3275%