ByteDance Seed 1.6 Flash

bytedance-seed/seed-1.6-flash

ByteDance Seed 1.6 Flash

via OpenRouter

Release Date

Dec 23rd, 2025

Context Size

256k

Benchmark Cost

$0.41

Speed

150.1 tok/s

Creative writing

64.26%

Rule following

71.47%

Utility

81.21%

Mathematics

100.00%

Tooling

79.92%

Language

64.96%

Logic

86.18%

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 0-shot Creative writingRule following	79	78	75	74	74	76%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	83	80	78	76	76	79%
Literary fiction: old friends reunite 0-shot Creative writingRule following	87	85	84	83	79	84%
Mystery: examining a crime scene 0-shot Creative writingRule following	93	82	79	78	78	82%
Romance: separated couple reunites 0-shot Creative writingRule following	85	82	82	79	77	81%
Thriller: chase through city streets 0-shot Creative writingRule following	87	85	85	85	76	84%
Detailed Writing Rules						80.84%
genre
Fantasy: entering an ancient ruin 0-shot Creative writingRule following	80	80	79	72	69	76%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	83	80	78	76	74	78%
Literary fiction: old friends reunite 0-shot Creative writingRule following	88	83	82	81	78	83%
Mystery: examining a crime scene 0-shot Creative writingRule following	84	80	78	77	76	79%
Romance: separated couple reunites 0-shot Creative writingRule following	85	82	80	80	80	81%
Thriller: chase through city streets 0-shot Creative writingRule following	83	82	79	78	77	80%
genre						79.49%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin 0-shot Creative writingRule following	84	80	78	76	75	79%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	87	81	80	79	79	81%
Literary fiction: old friends reunite 0-shot Creative writingRule following	86	85	81	79	75	81%
Mystery: examining a crime scene 0-shot Creative writingRule following	92	84	81	79	79	83%
Romance: separated couple reunites 0-shot Creative writingRule following	88	85	83	82	81	84%
Thriller: chase through city streets 0-shot Creative writingRule following	90	80	78	77	77	80%
Novelcrafter Default Prompt						81.37%
80.57%

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) 0-shot ToolingUtilityLogicRule following	82	80	76	76	75	74	73	71	71	69	75%
Large codex (40 entries), short passage (165 words) 0-shot ToolingUtilityLogicRule following	91	89	88	86	84	84	82	81	80	72	84%
Small codex (7 entries), long passage (734 words) 0-shot ToolingUtilityLogicRule following	97	93	90	88	84	84	83	80	80	79	86%
Small codex (7 entries), short passage (165 words) 0-shot ToolingUtilityLogicRule following	97	97	97	97	93	93	93	93	88	84	93%
matrix											84.40%
tiers
5 codex entries 0-shot ToolingUtilityLogicRule following	100	93	93	93	93	93	93	93	93	83	93%
10 codex entries 0-shot ToolingUtilityLogicRule following	100	94	94	94	94	94	94	94	92	89	94%
20 codex entries 0-shot ToolingUtilityLogicRule following	94	91	91	91	91	91	88	82	82	73	87%
40 codex entries 0-shot ToolingUtilityLogicRule following	93	93	93	90	90	87	87	84	76	72	87%
tiers											90.30%
87.35%

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 0-shot Utility	100	100	100	100	100	100	100	100	100	100	100%
Contextual pronoun 0-shot Utility	100	100	100	100	100	100	100	100	100	50	95%
Fruits excluding citrus 0-shot Utility	100	100	100	100	100	100	100	100	100	100	100%
Future event time 0-shot UtilityLogic	100	100	100	100	100	100	100	100	50	50	90%
Guess the pet 0-shot UtilityLogic	100	100	100	100	100	100	100	100	100	100	100%
Highest-rated movie 0-shot Utility	100	100	100	100	100	100	100	100	100	50	95%
Indirect birth year 0-shot UtilityMathematicsLogic	100	100	100	100	100	100	100	100	100	100	100%
What instrument does Lucy play? 0-shot UtilityLogic	100	100	100	100	100	100	100	100	50	50	90%
What's the color of the car? 0-shot UtilityLogic	100	100	100	100	100	100	100	100	100	100	100%
What's the correct time? 0-shot UtilityLogic	0	0	0	0	0	0	0	0	0	0	0%
Who's the sister? 0-shot UtilityLogic	100	100	100	100	100	100	100	100	100	100	100%
Who's the tallest? 0-shot UtilityLogic	100	100	100	100	100	100	100	100	100	100	100%
89.17%

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 0-shot Creative writingRule following	41	34	0	0	0	0	0	0	0	0	7%
Write 200 words with 50% dialogue 0-shot Creative writingRule following	100	99	71	50	49	47	41	4	2	0	46%
Write 200 words with 90% dialogue 0-shot Creative writingRule following	63	54	17	14	0	0	0	0	0	0	15%
dialogue-200											22.83%
dialogue-500
Write 500 words with 30% dialogue 0-shot Creative writingRule following	5	0	0	0	0	0	0	0	0	0	0%
Write 500 words with 50% dialogue 0-shot Creative writingRule following	47	43	40	23	18	16	13	13	0	0	21%
Write 500 words with 70% dialogue 0-shot Creative writingRule following	48	45	36	6	0	0	0	0	0	0	14%
dialogue-500											11.81%
Ungrouped
Write unattributed dialogue 0-shot Creative writingRule following	100	100	100	61	61	61	14	14	14	0	52%
22.31%

Language Comprehension

Does the model understand more than just English?

Scenario	#1	#2	#3	#4	#5	Total
Asking for directions (Dutch) 0-shot Language	100	100	0	0	0	40%
Asking for directions (German) 0-shot Language	100	100	0	0	0	40%
Friend got new kittens (German) 0-shot Language	0	0	0	0	0	0%
Friend got new kittens (Tagalog) 0-shot Language	100	100	100	100	0	80%
40.00%

Language Writing

Can the model generate text in different languages?

Scenario	#1	#2	#3	#4	#5	Total
Character dialogue (French) in a story 0-shot Language	100	100	100	91	90	96%
Character dialogue (German) in a story 0-shot Language	100	100	100	80	78	92%
Character dialogue (Hindi) in a story 0-shot Language	100	71	60	54	0	57%
Character dialogue (Italian) in a story 0-shot Language	100	100	100	93	92	97%
Character dialogue (Spanish) in a story 0-shot Language	94	93	89	89	50	83%
84.93%

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 0-shot Rule following	100	100	96	91	91	89	87	85	72	60	87%
Write sentences with 10 words each 0-shot Rule following	100	100	95	95	94	90	83	77	76	3	81%
Write sentences with 20 words each 0-shot Rule following	100	100	100	100	100	90	75	74	74	59	87%
85.14%

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 0-shot ToolingUtility	100	100	100	100	100	100	100	100	100	100	100%
Count chapters 0-shot ToolingUtility	100	100	100	100	100	100	100	100	100	0	90%
Count scenes 0-shot ToolingUtility	100	100	100	100	100	100	100	100	100	0	90%
outline-count											93.33%
pov-count
Count point of views for Jack and Olivia 0-shot ToolingUtility	100	100	100	100	100	100	100	100	100	100	100%
Count point of views for Jack Harper 0-shot ToolingUtility	100	100	100	100	100	100	100	100	0	0	80%
Count point of views for Olivia 0-shot ToolingUtility	100	100	100	100	0	0	0	0	0	0	40%
pov-count											73.33%
83.33%

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 0-shot ToolingUtility	0	0	0	0	0	0	0	0	0	0	0%
0.00%

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 0-shot Utility	100	100	0	0	0	0	0	0	0	0	20%
Simple 0-shot Utility	100	100	100	100	100	100	100	0	0	0	70%
Simple (1-shot) 1-shot Utility	100	100	100	100	100	100	100	100	100	0	90%
Simple (5-shot) Few-shot Utility	100	100	100	100	100	100	100	100	0	0	80%
Unattributed dialogue 0-shot Utility	100	100	100	100	100	100	100	0	0	0	70%
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 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
3 paragraph summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
5 paragraph summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
paragraphs											100.00%
sentences
1 sentence summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
3 sentence summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
10 sentence summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
20 sentence summary 0-shot Rule following	100	100	100	100	100	100	98	98	92	0	89%
50 sentence summary 0-shot Rule following	100	98	9	9	9	0	0	0	0	0	23%
sentences											82.27%
words
10 word summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
20 word summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	92	99%
50 word summary 0-shot Rule following	100	100	98	0	0	0	0	0	0	0	30%
100 word summary 0-shot Rule following	9	0	0	0	0	0	0	0	0	0	1%
200 word summary 0-shot Rule following	0	0	0	0	0	0	0	0	0	0	0%
words											45.99%
72.41%