Gemini 2.5 Flash (Reasoning)

google/gemini-2.5-flash

Gemini 2.5 Flash (Reasoning)

via OpenRouter

Release Date

Jun 17th, 2025

Context Size

Reasoning

Yes

Benchmark Cost

$5.73

Speed

198.2 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	76	72	72	72	72	73%
Horror: alone in an eerie place at night Creative WritingHallucination	83	79	78	76	73	78%
Literary fiction: old friends reunite Creative WritingHallucination	87	82	80	79	76	81%
Mystery: examining a crime scene Creative WritingHallucination	84	80	78	76	71	78%
Romance: separated couple reunites Creative WritingHallucination	82	80	78	77	75	78%
Thriller: chase through city streets Creative WritingHallucination	85	83	80	78	78	81%
Detailed Writing Rules						77.98%
genre
Fantasy: entering an ancient ruin Creative WritingHallucination	75	71	68	68	66	70%
Horror: alone in an eerie place at night Creative WritingHallucination	78	76	74	67	64	72%
Literary fiction: old friends reunite Creative WritingHallucination	82	75	72	70	69	74%
Mystery: examining a crime scene Creative WritingHallucination	83	81	80	79	69	78%
Romance: separated couple reunites Creative WritingHallucination	77	75	73	71	70	73%
Thriller: chase through city streets Creative WritingHallucination	85	83	81	79	77	81%
genre						74.62%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative WritingHallucination	75	75	73	72	71	73%
Horror: alone in an eerie place at night Creative WritingHallucination	81	80	80	75	73	78%
Literary fiction: old friends reunite Creative WritingHallucination	78	75	73	70	69	73%
Mystery: examining a crime scene Creative WritingHallucination	85	81	80	77	76	80%
Romance: separated couple reunites Creative WritingHallucination	75	74	73	73	72	74%
Thriller: chase through city streets Creative WritingHallucination	89	86	85	83	71	83%
Novelcrafter Default Prompt						76.65%
76.42%

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	96	96	96	94	94	95%
Medium: The Hollow (Inferred) ToolingReasoning	94	94	93	91	90	92%
Medium: Through the Thornveil (Scattered) ToolingReasoning	97	97	96	88	69	89%
Short: The Rusty Lantern (Explicit) ToolingReasoning	100	94	91	86	83	91%
91.93%

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	25	25	85%
Long text (~1594 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
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	100	100	100	100%
basic entries											94.38%
detailed entries
Long text (~1594 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	25	25	85%
Long text (~1594 words), small codex (11 detailed entries) Hallucination	100	100	25	25	25	25	25	25	25	25	40%
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	100	100%
detailed entries											79.38%
86.88%

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	97	96	95	95	95	95	95	95	93	91	95%
Large codex (40 entries), short passage (165 words) ToolingReasoning	100	98	96	96	96	94	93	93	93	91	95%
Small codex (7 entries), long passage (734 words) ToolingReasoning	100	100	100	97	97	95	91	91	87	87	95%
Small codex (7 entries), short passage (165 words) ToolingReasoning	100	100	100	100	100	100	100	100	100	100	100%
matrix											96.12%
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	100	100%
20 codex entries ToolingReasoning	100	97	97	97	96	92	89	89	88	88	93%
40 codex entries ToolingReasoning	100	100	100	100	100	100	97	95	95	92	98%
tiers											97.82%
96.97%

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	0	0	80%
Future event time Reasoning	100	100	100	100	100	100	100	100	100	100	100%
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	0	0	80%
What's the correct time? Reasoning	100	100	100	100	100	100	0	0	0	0	60%
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%
93.33%

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	64	50	50	43	30	26	12	0	0	0	27%
Write 200 words with 50% dialogue Rule FollowingUtility	100	98	77	50	50	50	50	50	49	0	57%
Write 200 words with 90% dialogue Rule FollowingUtility	53	50	50	50	49	49	49	38	37	18	44%
dialogue-200											42.94%
dialogue-500
Write 500 words with 30% dialogue Rule FollowingUtility	60	50	50	47	41	29	28	22	7	0	33%
Write 500 words with 50% dialogue Rule FollowingUtility	84	50	48	42	22	17	10	1	0	0	27%
Write 500 words with 70% dialogue Rule FollowingUtility	44	35	13	8	4	4	2	1	0	0	11%
dialogue-500											23.91%
Ungrouped
Write unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	61	14	87%
41.14%

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	0	80%
Friend got new kittens (German) Language	100	100	0	0	0	40%
Friend got new kittens (Tagalog) Language	100	100	100	100	100	100%
75.00%

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	100	100%
Character dialogue (Hindi) in a story Language	100	100	100	100	67	93%
Character dialogue (Italian) in a story Language	100	100	95	91	89	95%
Character dialogue (Spanish) in a story Language	100	100	100	95	92	97%
97.13%

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	99	99	99	99	97	97	96	95	95	98%
Write sentences with 10 words each Utility	97	89	87	86	85	84	78	75	71	65	82%
Write sentences with 20 words each Utility	51	34	12	10	9	6	3	1	0	0	13%
64.00%

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	50	50	0	80%
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											93.33%
96.67%

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	98	98	98	98	98	98%
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	99	99	99	99	99	99	95	99%
Passive voice → active voice Text EditingHallucination	96	95	95	95	94	94	93	94%
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	96	96	93	89	89	81	81	89%
Generic Prompt								97.85%
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	99	99	97	97	93	90	89	95%
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	98	98	97	97	97	96	94	97%
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								99.08%
98.46%

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	0	0	0	0	60%
Simple Rule Following	100	0	0	0	0	0	0	0	0	0	10%
Simple (1-shot) 1-shot Rule Following	0	0	0	0	0	0	0	0	0	0	0%
Simple (5-shot) Few-shot Rule Following	100	100	0	0	0	0	0	0	0	0	20%
Unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	100	100%
38.00%

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	98	100%
20 sentence summary Utility	100	100	98	92	92	92	77	27	27	9	72%
50 sentence summary Utility	100	98	92	77	54	54	54	9	9	0	55%
sentences											85.21%
words
10 word summary Utility	100	100	100	100	100	100	100	100	100	100	100%
20 word summary Utility	100	100	100	100	100	100	100	100	100	98	100%
50 word summary Utility	100	100	100	92	92	54	27	2	2	0	57%
100 word summary Utility	100	100	100	77	9	9	2	2	0	0	40%
200 word summary Utility	92	27	0	0	0	0	0	0	0	0	12%
words											61.71%
79.58%