Claude Haiku 5.5 (Reasoning, Max)

anthropic/claude-haiku-5.5

Claude Haiku 5.5 (Reasoning, Max)

via OpenRouter

Release Date

Oct 7th, 2026

Context Size

Reasoning

Yes

Benchmark Cost

$2.69

Speed

227.8 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	Total
Detailed Writing Rules
Fantasy: entering an ancient ruin Creative Writing Hallucination	–	–	–
Horror: alone in an eerie place at night Creative Writing Hallucination	–	–	–
Literary fiction: old friends reunite Creative Writing Hallucination	–	–	–
Mystery: examining a crime scene Creative Writing Hallucination	–	–	–
Romance: separated couple reunites Creative Writing Hallucination	–	–	–
Thriller: chase through city streets Creative Writing Hallucination	–	–	–
Detailed Writing Rules			–
genre
Fantasy: entering an ancient ruin Creative Writing Hallucination	–	–	–
Horror: alone in an eerie place at night Creative Writing Hallucination	89	88	89%
Literary fiction: old friends reunite Creative Writing Hallucination	–	–	–
Mystery: examining a crime scene Creative Writing Hallucination	–	–	–
Romance: separated couple reunites Creative Writing Hallucination	–	–	–
Thriller: chase through city streets Creative Writing Hallucination	91	–	91%
genre			89.82%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative Writing Hallucination	–	–	–
Horror: alone in an eerie place at night Creative Writing Hallucination	–	–	–
Literary fiction: old friends reunite Creative Writing Hallucination	–	–	–
Mystery: examining a crime scene Creative Writing Hallucination	–	–	–
Romance: separated couple reunites Creative Writing Hallucination	–	–	–
Thriller: chase through city streets Creative Writing Hallucination	–	–	–
Novelcrafter Default Prompt			–
89.82%

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	Total
Long: The Spire of Echoes (Dense) Tooling Reasoning	98	97	–	98%
Medium: The Hollow (Inferred) Tooling Reasoning	98	98	96	97%
Medium: Through the Thornveil (Scattered) Tooling Reasoning	98	98	–	98%
Short: The Rusty Lantern (Explicit) Tooling Reasoning	–	–	–	–
97.79%

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	Total
basic entries
Long text (~1594 words), big codex (51 entries) Hallucination	100	100	100	100	100	100	100%
Long text (~1594 words), small codex (11 entries) Hallucination	100	100	100	100	100	–	100%
Short text (~524 words), big codex (51 entries) Hallucination	100	100	100	–	–	–	100%
Short text (~524 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100%
basic entries							100.00%
detailed entries
Long text (~1594 words), big codex (51 detailed entries) Hallucination	100	–	–	–	–	–	100%
Long text (~1594 words), small codex (11 detailed entries) Hallucination	100	100	100	100	–	–	100%
Short text (~524 words), big codex (51 detailed entries) Hallucination	100	25	25	–	–	–	50%
Short text (~524 words), small codex (11 detailed entries) Hallucination	25	25	25	25	25	–	25%
detailed entries							68.75%
84.38%

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	Total
matrix
Large codex (40 entries), long passage (1,019 words) Tooling Reasoning	97	97	96	96	87	95%
Large codex (40 entries), short passage (165 words) Tooling Reasoning	96	96	94	92	–	94%
Small codex (7 entries), long passage (734 words) Tooling Reasoning	100	97	97	97	97	97%
Small codex (7 entries), short passage (165 words) Tooling Reasoning	100	100	–	–	–	100%
matrix						96.63%
tiers
5 codex entries Tooling Reasoning	100	100	100	100	–	100%
10 codex entries Tooling Reasoning	100	100	100	100	–	100%
20 codex entries Tooling Reasoning	94	92	89	–	–	92%
40 codex entries Tooling Reasoning	100	100	100	100	100	100%
tiers						97.95%
97.29%

Data extraction

Extract key details from a given block of text.

Scenario	#1	#2	#3	#4	#5	#6	Total
All valid emails Utility	100	100	100	–	–	–	100%
Contextual pronoun Utility	100	100	100	100	100	100	100%
Fruits excluding citrus Utility	100	100	100	–	–	–	100%
Future event time Reasoning	100	50	–	–	–	–	75%
Guess the pet Reasoning	100	100	100	100	–	–	100%
Highest-rated movie Reasoning	100	100	100	–	–	–	100%
Indirect birth year Reasoning	100	100	–	–	–	–	100%
What instrument does Lucy play? Reasoning	100	100	–	–	–	–	100%
What's the color of the car? Utility	100	100	100	100	100	100	100%
Who's the sister? Reasoning	100	–	–	–	–	–	100%
Who's the tallest? Reasoning	100	100	–	–	–	–	100%
97.73%

Dialogue tags

Various tasks related to dialogue tags in text.

Scenario	#1	#2	#3	#4	#5	Total
dialogue-200
Write 200 words with 10% dialogue Rule Following Utility	100	100	100	–	–	100%
Write 200 words with 50% dialogue Rule Following Utility	100	100	100	93	–	98%
Write 200 words with 90% dialogue Rule Following Utility	100	100	100	100	98	100%
dialogue-200						99.31%
dialogue-500
Write 500 words with 30% dialogue Rule Following Utility	100	98	–	–	–	99%
Write 500 words with 50% dialogue Rule Following Utility	100	100	76	–	–	92%
Write 500 words with 70% dialogue Rule Following Utility	100	98	95	0	–	73%
dialogue-500						87.99%
Ungrouped
Write unattributed dialogue Rule Following	100	100	100	100	–	100%
94.56%

Language Comprehension

Does the model understand more than just English?

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

Language Writing

Can the model generate text in different languages?

Scenario	#1	#2	#3	Total
Character dialogue (French) in a story Language	–	–	–	–
Character dialogue (German) in a story Language	100	100	–	100%
Character dialogue (Hindi) in a story Language	–	–	–	–
Character dialogue (Italian) in a story Language	100	97	97	98%
Character dialogue (Spanish) in a story Language	100	–	–	100%
99.41%

N-Length Sentences

Write sentences with exactly N words

Scenario	#1	#2	#3	#4	#5	Total
Write sentences with 5 words each Utility	–	–	–	–	–	–
Write sentences with 10 words each Utility	100	100	95	94	90	96%
Write sentences with 20 words each Utility	100	100	91	–	–	97%
96.41%

Novel outline

Handle questions about the outline of a novel in various formats

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

Relationship tree

Extracts a deterministic XML family and relationship tree from cumulative literary prose.

Scenario	#1	Total
Core relationship tree Tooling Reasoning Hallucination	98	98%
Family relationship tree Tooling Reasoning Hallucination	–	–
98.41%

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	Total
Generic Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	–	–	100%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	–	100%
Combined: 3rd person past → 1st person present Text Editing	99	98	–	–	–	99%
Expand all contractions Text Editing	100	100	100	100	–	100%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	100	100	–	–	100%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	100	100	100	100	–	100%
Passive voice → active voice Text Editing Hallucination	96	96	–	–	–	96%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	99	–	–	100%
Tense rewriting: past to present Text Editing	100	100	99	–	–	100%
Generic Prompt						99.32%
Specific Prompt
Avoid said/asked/replied/answered Text Editing	100	100	–	–	–	100%
Character rename: Elena->Mirabel, Gregor->Aldric Text Editing	100	100	100	100	100	100%
Combined: 3rd person past → 1st person present Text Editing	99	99	99	–	–	99%
Expand all contractions Text Editing	100	100	100	–	–	100%
Location rename: market square, outer ring, bridge, northern mines Text Editing	100	100	100	–	–	100%
Multi-character gender swap: Priya(F)->Rohan(M), Mara unchanged Text Editing	100	100	100	–	–	100%
Passive voice → active voice Text Editing Hallucination	98	97	–	–	–	97%
POV shift: 3rd person to 1st person (Elena's perspective) Text Editing	100	100	–	–	–	100%
Tense rewriting: past to present Text Editing	100	100	100	–	–	100%
Specific Prompt						99.64%
99.48%

Tool usage within Novelcrafter

Output messages that are related to tool usage within Novelcrafter

Scenario	#1	#2	#3	#4	Total
Create alternate prose sections Tooling	100	100	100	100	100%
100.00%

Voice/dialogue sheets

Extract dialogue from given text as voice sheets.

Scenario	#1	#2	#3	#4	#5	Total
Multiple speakers Rule Following	100	0	0	–	–	33%
Simple Rule Following	0	0	–	–	–	0%
Simple (1-shot) 1-shot Rule Following	100	100	100	0	–	75%
Simple (5-shot) Few-shot Rule Following	100	100	100	100	100	100%
Unattributed dialogue Rule Following	100	100	100	100	100	100%
61.67%

Write N of X

Write exactly N words/sentences/paragraphs...

Scenario	#1	#2	#3	#4	#5	Total
paragraphs
1 paragraph summary Utility	100	100	100	–	–	100%
3 paragraph summary Utility	100	100	–	–	–	100%
5 paragraph summary Utility	100	100	100	100	–	100%
paragraphs						100.00%
sentences
1 sentence summary Utility	100	100	100	100	–	100%
3 sentence summary Utility	100	100	–	–	–	100%
10 sentence summary Utility	100	100	–	–	–	100%
20 sentence summary Utility	100	100	100	–	–	100%
50 sentence summary Utility	100	100	100	100	100	100%
sentences						100.00%
words
10 word summary Utility	100	100	100	–	–	100%
20 word summary Utility	100	100	100	100	–	100%
50 word summary Utility	100	100	–	–	–	100%
100 word summary Utility	100	100	100	–	–	100%
200 word summary Utility	100	100	100	100	–	100%
words						100.00%
100.00%