Aion 2.0 - NC Bench

aion-labs/aion-2.0

Aion 2.0

via OpenRouter

Release Date

Feb 23rd, 2026

Context Size

131k

Reasoning

Yes

Benchmark Cost

$3.78

Speed

38.6 tok/s

Subcategories

Bad Writing Habits

Detects common prose quality anti-patterns in AI-generated creative writing, including passive voice, past progressive overuse, weak dialogue tags, filter words, purple prose, cliches, AI-ism words/adverbs/names, and more.

Scenario	#1	#2	#3	#4	#5	Total
Detailed Writing Rules
Fantasy: entering an ancient ruin Creative WritingHallucination	80	80	77	76	75	78%
Horror: alone in an eerie place at night Creative WritingHallucination	86	86	83	83	75	83%
Literary fiction: old friends reunite Creative WritingHallucination	86	86	81	78	76	82%
Mystery: examining a crime scene Creative WritingHallucination	84	84	82	81	81	82%
Romance: separated couple reunites Creative WritingHallucination	85	83	82	78	76	81%
Thriller: chase through city streets Creative WritingHallucination	88	85	84	82	78	84%
Detailed Writing Rules						81.43%
genre
Fantasy: entering an ancient ruin Creative WritingHallucination	73	72	72	71	70	72%
Horror: alone in an eerie place at night Creative WritingHallucination	81	77	74	74	71	75%
Literary fiction: old friends reunite Creative WritingHallucination	81	78	78	75	74	77%
Mystery: examining a crime scene Creative WritingHallucination	81	79	74	72	69	75%
Romance: separated couple reunites Creative WritingHallucination	84	81	80	79	76	80%
Thriller: chase through city streets Creative WritingHallucination	83	81	80	79	75	80%
genre						76.49%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative WritingHallucination	75	73	73	73	67	72%
Horror: alone in an eerie place at night Creative WritingHallucination	86	85	85	84	76	83%
Literary fiction: old friends reunite Creative WritingHallucination	80	80	79	75	75	78%
Mystery: examining a crime scene Creative WritingHallucination	84	81	80	80	74	80%
Romance: separated couple reunites Creative WritingHallucination	80	80	80	79	76	79%
Thriller: chase through city streets Creative WritingHallucination	88	87	84	82	79	84%
Novelcrafter Default Prompt						79.29%
79.07%

Codex Extraction

Evaluates a model's ability to extract structured codex entries (characters, locations, objects, lore) from prose passages and return them as well-formed XML.

Scenario	#1	#2	#3	#4	#5	Total
Long: The Spire of Echoes (Dense) ToolingReasoning	98	98	98	98	96	97%
Medium: The Hollow (Inferred) ToolingReasoning	99	98	98	97	94	97%
Medium: Through the Thornveil (Scattered) ToolingReasoning	98	98	98	98	94	97%
Short: The Rusty Lantern (Explicit) ToolingReasoning	100	100	98	98	96	98%
97.46%

Codex Red Herring (False Positive Detection)

Tests whether models correctly report "no violations" when a codex is fully consistent with the prose passage. Models that hallucinate false violations (false positives) fail. Uses a 2×2 matrix of text length × codex size, with bare and detailed-entry variants.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
basic entries
Long text (~1594 words), big codex (51 entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Long text (~1594 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	100	100	25	93%
Short text (~524 words), big codex (51 entries) Hallucination	100	100	100	100	100	100	100	100	100	25	93%
Short text (~524 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	25	25	25	78%
basic entries											90.63%
detailed entries
Long text (~1594 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Long text (~1594 words), small codex (11 detailed entries) Hallucination	100	100	100	100	25	25	25	25	25	25	55%
Short text (~524 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	25	93%
Short text (~524 words), small codex (11 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	25	93%
detailed entries											85.00%
87.81%

Codex Violation Detection

Detects factual inconsistencies between a story bible and prose passages. The model must output structured XML identifying each violation with paragraph number and substring.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
matrix
Large codex (40 entries), long passage (1,019 words) ToolingReasoning	100	99	98	97	96	96	96	95	94	3	87%
Large codex (40 entries), short passage (165 words) ToolingReasoning	98	98	96	96	96	96	95	94	93	90	95%
Small codex (7 entries), long passage (734 words) ToolingReasoning	100	100	100	97	97	97	97	97	92	88	96%
Small codex (7 entries), short passage (165 words) ToolingReasoning	100	100	100	100	100	100	100	100	97	0	90%
matrix											92.22%
tiers
5 codex entries ToolingReasoning	100	100	100	100	100	100	100	100	100	100	100%
10 codex entries ToolingReasoning	100	100	100	100	100	100	100	100	100	92	99%
20 codex entries ToolingReasoning	100	100	97	97	96	94	92	89	88	88	94%
40 codex entries ToolingReasoning	100	100	100	100	100	97	97	97	97	97	98%
tiers											97.94%
95.08%

Data extraction

Extract key details from a given block of text.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
All valid emails Utility	100	100	100	100	100	100	100	100	100	100	100%
Contextual pronoun Utility	100	100	100	100	100	100	100	100	100	100	100%
Fruits excluding citrus Utility	100	100	100	100	100	100	100	100	100	100	100%
Future event time Reasoning	100	100	100	100	100	100	50	50	50	50	80%
Guess the pet Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Highest-rated movie Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Indirect birth year Reasoning	100	100	100	100	100	100	100	100	100	100	100%
What instrument does Lucy play? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
What's the color of the car? Utility	100	100	100	100	100	100	100	100	100	100	100%
What's the correct time? Reasoning	0	0	0	0	0	0	0	0	0	0	0%
Who's the sister? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
Who's the tallest? Reasoning	100	100	100	100	100	100	100	100	100	100	100%
90.00%

Dialogue tags

Various tasks related to dialogue tags in text.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
dialogue-200
Write 200 words with 10% dialogue Rule FollowingUtility	100	91	72	49	48	44	2	0	0	0	41%
Write 200 words with 50% dialogue Rule FollowingUtility	73	47	43	10	0	0	0	0	0	0	17%
Write 200 words with 90% dialogue Rule FollowingUtility	59	55	51	50	47	43	42	39	32	15	43%
dialogue-200											33.69%
dialogue-500
Write 500 words with 30% dialogue Rule FollowingUtility	38	2	1	1	0	0	0	0	0	0	4%
Write 500 words with 50% dialogue Rule FollowingUtility	50	50	48	30	10	5	0	0	0	0	19%
Write 500 words with 70% dialogue Rule FollowingUtility	61	50	50	48	34	34	5	3	0	0	28%
dialogue-500											17.29%
Ungrouped
Write unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	100	100%
36.13%

Language Comprehension

Does the model understand more than just English?

Scenario	#1	#2	#3	#4	#5	Total
Asking for directions (Dutch) Language	100	100	100	100	100	100%
Asking for directions (German) Language	100	100	100	100	100	100%
Friend got new kittens (German) Language	100	100	100	100	100	100%
Friend got new kittens (Tagalog) Language	100	100	100	100	100	100%
100.00%

Language Writing

Can the model generate text in different languages?

Scenario	#1	#2	#3	#4	#5	Total
Character dialogue (French) in a story Language	100	100	100	100	100	100%
Character dialogue (German) in a story Language	100	100	100	100	91	98%
Character dialogue (Hindi) in a story Language	100	100	63	60	50	75%
Character dialogue (Italian) in a story Language	100	100	100	100	100	100%
Character dialogue (Spanish) in a story Language	100	100	95	94	56	89%
92.34%

N-Length Sentences

Write sentences with exactly N words

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Write sentences with 5 words each Utility	100	100	100	100	100	100	100	97	90	83	97%
Write sentences with 10 words each Utility	100	100	100	100	100	100	100	100	97	90	99%
Write sentences with 20 words each Utility	100	100	100	100	100	100	100	93	92	54	94%
96.57%

Novel outline

Handle questions about the outline of a novel in various formats

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
outline-count
Count acts Utility	100	100	100	100	100	100	100	100	100	100	100%
Count chapters Utility	100	100	100	100	100	100	100	100	100	100	100%
Count scenes Utility	100	100	100	100	100	100	100	100	100	100	100%
outline-count											100.00%
pov-count
Count point of views for Jack and Olivia Utility	100	100	100	100	100	100	100	100	100	100	100%
Count point of views for Jack Harper Utility	100	100	100	100	100	100	100	100	100	100	100%
Count point of views for Olivia Utility	100	100	100	100	100	100	100	100	100	100	100%
pov-count											100.00%
100.00%

Text Replacement

Tests deterministic text transformations: renaming characters/locations, expanding contractions, tense rewriting, POV shifts, gender swaps, combined transformations, and word avoidance. Scored by checking each expected change independently.

Scenario	#1	#2	#3	#4	#5	#6	#7	Total
Generic Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	100	100	100	100	100%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	100	100	100	100%
Combined: 3rd person past → 1st person present Text Editing	99	99	99	99	99	99	99	99%
Expand all contractions Text Editing	100	100	100	100	100	99	99	100%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	100	100	100	100	100	100	100%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	100	100	100	100	100	100	100	100%
Passive voice → active voice Text EditingHallucination	98	98	96	96	96	95	94	96%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	100	100	100	100	96	99%
Tense rewriting: past to present Text Editing	100	97	97	93	92	89	81	93%
Generic Prompt								98.57%
Specific Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	100	100	100	72	96%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	100	100	100	100%
Combined: 3rd person past → 1st person present Text Editing	100	100	100	100	100	100	99	100%
Expand all contractions Text Editing	100	100	100	100	100	100	100	100%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	100	100	100	100	100	100	100%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	100	100	100	100	100	100	100	100%
Passive voice → active voice Text EditingHallucination	99	98	98	98	97	96	0	84%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	100	100	100	100	100	100%
Tense rewriting: past to present Text Editing	100	100	100	100	100	100	100	100%
Specific Prompt								97.77%
98.17%

Tool usage within Novelcrafter

Output messages that are related to tool usage within Novelcrafter

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Create alternate prose sections Tooling	100	100	100	100	100	100	100	100	100	100	100%
100.00%

Voice/dialogue sheets

Extract dialogue from given text as voice sheets.

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
Multiple speakers Rule Following	100	100	100	100	100	100	100	0	0	0	70%
Simple Rule Following	100	100	100	100	100	100	0	0	0	0	60%
Simple (1-shot) 1-shot Rule Following	100	100	100	100	100	0	0	0	0	0	50%
Simple (5-shot) Few-shot Rule Following	100	100	100	100	100	100	0	0	0	0	60%
Unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	0	90%
66.00%

Write N of X

Write exactly N words/sentences/paragraphs...

Scenario	#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	Total
paragraphs
1 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
3 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
5 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
paragraphs											100.00%
sentences
1 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
3 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
10 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
20 sentence summary Utility	100	100	100	100	100	100	100	100	100	100	100%
50 sentence summary Utility	100	100	100	100	54	2	0	0	0	0	46%
sentences											89.10%
words
10 word summary Utility	100	100	100	100	100	100	100	98	98	98	99%
20 word summary Utility	100	100	100	100	100	100	100	100	92	77	97%
50 word summary Utility	100	100	100	100	100	100	100	100	77	0	88%
100 word summary Utility	100	100	100	100	100	98	77	0	0	0	68%
200 word summary Utility	100	92	0	0	0	0	0	0	0	0	19%
words											74.19%
85.88%