DeepSeek V4 Flash (Reasoning)

deepseek/deepseek-v4-flash

DeepSeek V4 Flash (Reasoning)

via OpenRouter

Release Date

Apr 24th, 2026

Context Size

Reasoning

Yes

Benchmark Cost

$0.41

Speed

64.8 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	#3	#4	#5	Total
Detailed Writing Rules
Fantasy: entering an ancient ruin Creative Writing Hallucination	81	78	76	74	72	76%
Horror: alone in an eerie place at night Creative Writing Hallucination	90	89	87	84	80	86%
Literary fiction: old friends reunite Creative Writing Hallucination	88	87	82	81	79	84%
Mystery: examining a crime scene Creative Writing Hallucination	91	91	88	87	86	89%
Romance: separated couple reunites Creative Writing Hallucination	93	90	88	86	86	88%
Thriller: chase through city streets Creative Writing Hallucination	93	92	89	88	85	89%
Detailed Writing Rules						85.34%
genre
Fantasy: entering an ancient ruin Creative Writing Hallucination	83	78	77	72	72	76%
Horror: alone in an eerie place at night Creative Writing Hallucination	83	82	80	80	78	81%
Literary fiction: old friends reunite Creative Writing Hallucination	84	83	82	79	78	81%
Mystery: examining a crime scene Creative Writing Hallucination	82	82	81	77	73	79%
Romance: separated couple reunites Creative Writing Hallucination	86	83	82	77	77	81%
Thriller: chase through city streets Creative Writing Hallucination	84	82	79	74	74	79%
genre						79.46%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin Creative Writing Hallucination	80	78	76	76	74	77%
Horror: alone in an eerie place at night Creative Writing Hallucination	90	84	83	77	76	82%
Literary fiction: old friends reunite Creative Writing Hallucination	82	81	81	80	77	80%
Mystery: examining a crime scene Creative Writing Hallucination	87	85	83	81	77	83%
Romance: separated couple reunites Creative Writing Hallucination	86	86	84	83	74	83%
Thriller: chase through city streets Creative Writing Hallucination	86	82	82	77	73	80%
Novelcrafter Default Prompt						80.78%
81.86%

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	97	97	96	96	97%
Medium: The Hollow (Inferred) Tooling Reasoning	98	97	97	97	95	97%
Medium: Through the Thornveil (Scattered) Tooling Reasoning	97	96	96	96	95	96%
Short: The Rusty Lantern (Explicit) Tooling Reasoning	100	99	99	99	99	99%
97.06%

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	25	25	25	78%
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	25	25	85%
Short text (~524 words), small codex (11 entries) Hallucination	100	100	100	100	100	100	100	25	25	17	77%
basic entries											84.79%
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	100	100	100	100	25	25	85%
Short text (~524 words), big codex (51 detailed entries) Hallucination	100	100	100	100	100	100	100	100	100	100	100%
Short text (~524 words), small codex (11 detailed entries) Hallucination	100	100	100	100	100	100	100	100	25	25	85%
detailed entries											92.50%
88.65%

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	98	97	97	96	96	96	95	95	93	92	96%
Large codex (40 entries), short passage (165 words) Tooling Reasoning	100	100	100	97	97	96	96	95	91	91	96%
Small codex (7 entries), long passage (734 words) Tooling Reasoning	100	100	97	97	97	95	92	92	88	87	94%
Small codex (7 entries), short passage (165 words) Tooling Reasoning	100	100	100	100	100	95	95	95	95	95	98%
matrix											96.05%
tiers
5 codex entries Tooling Reasoning	100	100	100	100	100	100	100	100	100	91	99%
10 codex entries Tooling Reasoning	100	100	100	100	100	100	100	100	92	92	98%
20 codex entries Tooling Reasoning	100	100	96	96	96	94	92	92	85	85	94%
40 codex entries Tooling Reasoning	100	100	100	100	100	100	100	100	97	92	99%
tiers											97.50%
96.77%

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	100	100	100	50	95%
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%
91.25%

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	50	50	48	44	41	41	38	30	18	4	36%
Write 200 words with 50% dialogue Rule Following Utility	50	50	41	22	14	7	5	1	0	0	19%
Write 200 words with 90% dialogue Rule Following Utility	99	95	80	75	71	66	50	50	50	41	68%
dialogue-200											40.96%
dialogue-500
Write 500 words with 30% dialogue Rule Following Utility	48	41	38	0	0	0	0	0	0	0	13%
Write 500 words with 50% dialogue Rule Following Utility	45	30	14	7	0	0	0	0	0	0	10%
Write 500 words with 70% dialogue Rule Following Utility	34	7	2	2	0	0	0	0	0	0	5%
dialogue-500											8.94%
Ungrouped
Write unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	100	100%
35.67%

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	0	80%
Character dialogue (German) in a story Language	100	100	100	100	100	100%
Character dialogue (Hindi) in a story Language	100	100	50	50	45	69%
Character dialogue (Italian) in a story Language	100	100	100	100	92	98%
Character dialogue (Spanish) in a story Language	100	100	100	100	100	100%
89.51%

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	93	87	87	81	81	80	72	70	61	53	76%
Write sentences with 10 words each Utility	100	95	78	77	77	73	71	40	37	18	67%
Write sentences with 20 words each Utility	100	100	100	20	0	0	0	0	0	0	32%
58.33%

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	50	50	90%
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											96.67%
98.33%

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	96	99%
Expand all contractions Text Editing	100	100	100	100	100	100	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 Editing Hallucination	97	96	95	95	94	94	87	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	100	100	99	99	99	99	81	97%
Generic Prompt								98.82%
Specific Prompt
Avoid said/asked/replied/answered Text Editing	100	100	100	72	69	69	56	81%
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	99	99	97	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	99	98	98	96	95	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	99	96	95	99%
Specific Prompt								97.36%
98.09%

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	67	67	93%
93.33%

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	0	0	0	0	0	0	0	30%
Simple Rule Following	100	100	100	100	100	100	100	0	0	0	70%
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	0	90%
Unattributed dialogue Rule Following	100	100	100	100	100	100	100	100	100	100	100%
78.00%

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	100	100	100	100	100	100	100	100	100%
50 sentence summary Utility	100	100	100	100	100	100	54	2	0	0	66%
sentences											93.07%
words
10 word summary Utility	100	100	100	100	100	100	100	100	98	98	100%
20 word summary Utility	100	100	100	100	100	98	98	98	98	92	99%
50 word summary Utility	98	92	92	77	54	27	27	27	9	2	51%
100 word summary Utility	100	100	2	0	0	0	0	0	0	0	20%
200 word summary Utility	98	9	2	0	0	0	0	0	0	0	11%
words											55.99%
80.41%