Claude Haiku 4.5 - NC Bench

anthropic/claude-haiku-4.5

Claude Haiku 4.5

via OpenRouter

Release Date

Oct 15th, 2025

Context Size

200k

Reasoning

Benchmark Cost

$5.92

Speed

96.3 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 Writing Hallucination	80	77	72	71	69	74%
Horror: alone in an eerie place at night Creative Writing Hallucination	87	86	84	83	82	84%
Literary fiction: old friends reunite Creative Writing Hallucination	86	84	84	84	80	84%
Mystery: examining a crime scene Creative Writing Hallucination	89	89	87	86	84	87%
Romance: separated couple reunites Creative Writing Hallucination	89	78	78	77	76	79%
Thriller: chase through city streets Creative Writing Hallucination	87	87	83	82	76	83%
Detailed Writing Rules						81.91%
genre
Fantasy: entering an ancient ruin Creative Writing Hallucination	77	75	75	73	68	74%
Horror: alone in an eerie place at night Creative Writing Hallucination	88	80	78	74	65	77%
Literary fiction: old friends reunite Creative Writing Hallucination	82	79	79	78	74	78%
Mystery: examining a crime scene Creative Writing Hallucination	80	79	73	69	67	74%
Romance: separated couple reunites Creative Writing Hallucination	78	78	76	72	68	74%
Thriller: chase through city streets Creative Writing Hallucination	86	82	80	80	72	80%
genre						76.13%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative Writing Hallucination	82	78	74	73	71	76%
Horror: alone in an eerie place at night Creative Writing Hallucination	84	84	84	78	77	81%
Literary fiction: old friends reunite Creative Writing Hallucination	79	77	75	73	73	76%
Mystery: examining a crime scene Creative Writing Hallucination	87	85	83	78	69	80%
Romance: separated couple reunites Creative Writing Hallucination	86	80	78	77	72	79%
Thriller: chase through city streets Creative Writing Hallucination	88	88	86	83	81	85%
Novelcrafter Default Prompt						79.41%
79.15%

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) Tooling Reasoning	97	96	96	96	96	96%
Medium: The Hollow (Inferred) Tooling Reasoning	96	96	95	95	95	95%
Medium: Through the Thornveil (Scattered) Tooling Reasoning	98	97	97	97	97	97%
Short: The Rusty Lantern (Explicit) Tooling Reasoning	95	94	94	94	86	93%
95.47%

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	50	38	38	17	13	13	13	10	10	10	21%
Long text (~1594 words), small codex (11 entries) Hallucination	50	50	50	50	50	50	50	50	50	42	49%
Short text (~524 words), big codex (51 entries) Hallucination	100	50	50	50	50	50	50	50	50	42	54%
Short text (~524 words), small codex (11 entries) Hallucination	100	100	50	50	50	50	50	50	50	50	60%
basic entries											46.06%
detailed entries
Long text (~1594 words), big codex (51 detailed entries) Hallucination	50	50	50	50	50	50	50	50	50	42	49%
Long text (~1594 words), small codex (11 detailed entries) Hallucination	50	50	50	50	50	50	50	42	38	35	46%
Short text (~524 words), big codex (51 detailed entries) Hallucination	50	50	50	42	42	42	38	25	25	17	38%
Short text (~524 words), small codex (11 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	50	95%
detailed entries											57.13%
51.59%

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) Tooling Reasoning	84	79	79	77	76	76	75	75	75	72	77%
Large codex (40 entries), short passage (165 words) Tooling Reasoning	94	89	89	89	85	85	83	81	3	3	70%
Small codex (7 entries), long passage (734 words) Tooling Reasoning	93	93	93	93	93	93	93	93	93	93	93%
Small codex (7 entries), short passage (165 words) Tooling Reasoning	88	88	88	88	88	88	88	79	79	79	85%
matrix											81.42%
tiers
5 codex entries Tooling Reasoning	83	83	83	83	76	76	75	67	67	67	76%
10 codex entries Tooling Reasoning	86	86	86	86	86	86	86	86	86	86	86%
20 codex entries Tooling Reasoning	97	97	97	94	94	89	86	86	85	3	83%
40 codex entries Tooling Reasoning	97	97	92	88	88	88	88	83	79	3	80%
tiers											81.27%
81.35%

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	50	50	50	50	50	50	50	50	50	50	50%
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%
87.50%

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 Following Utility	100	100	99	96	95	94	68	50	32	30	76%
Write 200 words with 50% dialogue Rule Following Utility	92	88	70	60	60	45	34	22	12	0	48%
Write 200 words with 90% dialogue Rule Following Utility	99	97	88	87	71	53	52	50	44	39	68%
dialogue-200											64.27%
dialogue-500
Write 500 words with 30% dialogue Rule Following Utility	50	47	26	22	3	1	0	0	0	0	15%
Write 500 words with 50% dialogue Rule Following Utility	50	50	34	5	1	0	0	0	0	0	14%
Write 500 words with 70% dialogue Rule Following Utility	52	6	4	2	1	1	1	0	0	0	7%
dialogue-500											11.85%
Ungrouped
Write unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	61	61	92%
45.78%

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	0	80%
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%
95.00%

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	91	77	94%
Character dialogue (German) in a story Language	100	100	94	88	79	92%
Character dialogue (Hindi) in a story Language	100	100	100	60	53	83%
Character dialogue (Italian) in a story Language	100	100	94	93	78	93%
Character dialogue (Spanish) in a story Language	100	100	82	65	63	82%
88.67%

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	99	99	99	98	97	92	90	88	86	84	93%
Write sentences with 10 words each Utility	89	89	86	86	82	77	74	74	71	67	80%
Write sentences with 20 words each Utility	67	66	57	50	36	10	0	0	0	0	29%
67.10%

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	0	0	0	0	0	50%
outline-count											83.33%
pov-count
Count point of views for Jack and Olivia Utility	100	100	100	100	100	100	50	0	0	0	65%
Count point of views for Jack Harper Utility	100	100	100	100	100	100	100	100	100	0	90%
Count point of views for Olivia Utility	100	100	100	100	0	0	0	0	0	0	40%
pov-count											65.00%
74.17%

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	100	99	99	99	99	99	99	99%
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 Editing Hallucination	99	96	95	94	94	93	93	95%
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	97	97	97	97	97	97	96	97%
Generic Prompt								98.98%
Specific 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	100	100	99	99	99	99	99	99%
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 Editing Hallucination	99	97	96	96	95	93	93	96%
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								99.45%
99.22%

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	100	100	100	100%
Simple Rule Following	100	0	0	0	0	0	0	0	0	0	10%
Simple (1-shot) 1-shot Rule Following	100	100	100	100	100	100	100	100	100	100	100%
Simple (5-shot) Few-shot Rule Following	100	100	100	100	100	100	100	100	100	100	100%
Unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	100	100%
82.00%

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	0	90%
3 paragraph summary Utility	100	100	100	100	100	100	100	100	100	100	100%
5 paragraph summary Utility	100	100	0	0	0	0	0	0	0	0	20%
paragraphs											70.00%
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	98	92	77	77	77	27	27	27	9	0	51%
50 sentence summary Utility	0	0	0	0	0	0	0	0	0	0	0%
sentences											70.28%
words
10 word summary Utility	100	100	100	100	100	100	100	100	100	98	100%
20 word summary Utility	100	100	100	98	77	54	54	27	27	9	65%
50 word summary Utility	100	100	98	98	77	77	27	9	2	0	59%
100 word summary Utility	98	0	0	0	0	0	0	0	0	0	10%
200 word summary Utility	92	0	0	0	0	0	0	0	0	0	9%
words											48.50%
61.84%