ByteDance Seed 1.6

bytedance-seed/seed-1.6

ByteDance Seed 1.6

via OpenRouter

Release Date

Dec 23rd, 2025

Context Size

256k

Benchmark Cost

$3.24

Speed

40.3 tok/s

Creative writing

67.51%

Rule following

78.74%

Utility

89.58%

Mathematics

100.00%

Tooling

89.44%

Language

95.15%

Logic

91.88%

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	83	79	75	75	73	77%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	82	77	74	74	74	76%
Literary fiction: old friends reunite 0-shot Creative writingRule following	82	82	81	80	79	81%
Mystery: examining a crime scene 0-shot Creative writingRule following	84	83	80	78	69	79%
Romance: separated couple reunites 0-shot Creative writingRule following	89	88	81	79	76	83%
Thriller: chase through city streets 0-shot Creative writingRule following	83	78	77	77	74	78%
Detailed Writing Rules						78.86%
genre
Fantasy: entering an ancient ruin 0-shot Creative writingRule following	84	78	74	73	73	76%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	71	70	68	67	67	69%
Literary fiction: old friends reunite 0-shot Creative writingRule following	79	77	76	75	75	77%
Mystery: examining a crime scene 0-shot Creative writingRule following	78	76	75	74	74	75%
Romance: separated couple reunites 0-shot Creative writingRule following	78	76	74	70	69	73%
Thriller: chase through city streets 0-shot Creative writingRule following	80	79	77	75	69	76%
genre						74.39%
Novelcrafter Default Prompt
Fantasy: entering an ancient ruin 0-shot Creative writingRule following	78	78	75	74	73	76%
Horror: alone in an eerie place at night 0-shot Creative writingRule following	74	73	73	69	65	71%
Literary fiction: old friends reunite 0-shot Creative writingRule following	78	78	75	73	70	75%
Mystery: examining a crime scene 0-shot Creative writingRule following	85	84	81	79	71	80%
Romance: separated couple reunites 0-shot Creative writingRule following	83	82	76	73	73	77%
Thriller: chase through city streets 0-shot Creative writingRule following	80	76	75	73	73	76%
Novelcrafter Default Prompt						75.67%
76.31%

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	97	96	95	94	94	93	93	92	89	89	93%
Large codex (40 entries), short passage (165 words) 0-shot ToolingUtilityLogicRule following	100	98	98	98	96	96	96	96	96	95	97%
Small codex (7 entries), long passage (734 words) 0-shot ToolingUtilityLogicRule following	97	97	97	97	97	97	97	88	88	88	94%
Small codex (7 entries), short passage (165 words) 0-shot ToolingUtilityLogicRule following	100	100	100	100	100	100	100	100	100	100	100%
matrix											96.05%
tiers
5 codex entries 0-shot ToolingUtilityLogicRule following	100	100	100	100	100	100	100	100	100	100	100%
10 codex entries 0-shot ToolingUtilityLogicRule following	100	100	100	100	100	100	100	100	100	92	99%
20 codex entries 0-shot ToolingUtilityLogicRule following	92	92	89	89	89	89	89	89	89	89	90%
40 codex entries 0-shot ToolingUtilityLogicRule following	100	100	100	100	100	100	97	92	92	88	97%
tiers											96.45%
96.25%

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	100	100%
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	100	100	100%
Guess the pet 0-shot UtilityLogic	100	100	100	100	100	100	100	100	100	100	100%
Highest-rated movie 0-shot Utility	100	50	50	50	50	50	50	50	50	50	55%
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	100	100	100%
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%
87.92%

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	100	99	84	51	50	50	49	49	29	18	58%
Write 200 words with 50% dialogue 0-shot Creative writingRule following	99	91	70	69	52	50	50	49	47	0	58%
Write 200 words with 90% dialogue 0-shot Creative writingRule following	100	96	87	64	56	50	50	41	0	0	54%
dialogue-200											56.62%
dialogue-500
Write 500 words with 30% dialogue 0-shot Creative writingRule following	69	45	24	10	4	2	2	2	0	0	16%
Write 500 words with 50% dialogue 0-shot Creative writingRule following	48	33	32	6	3	1	1	0	0	0	12%
Write 500 words with 70% dialogue 0-shot Creative writingRule following	50	49	43	43	41	27	5	0	0	0	26%
dialogue-500											18.09%
Ungrouped
Write unattributed dialogue 0-shot Creative writingRule following	100	100	100	100	100	100	100	100	100	0	90%
44.87%

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	100	100	100	100%
Asking for directions (German) 0-shot Language	100	100	100	100	100	100%
Friend got new kittens (German) 0-shot Language	100	100	100	100	100	100%
Friend got new kittens (Tagalog) 0-shot 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 0-shot Language	100	100	100	100	100	100%
Character dialogue (German) in a story 0-shot Language	100	100	100	100	100	100%
Character dialogue (Hindi) in a story 0-shot Language	63	60	55	55	50	56%
Character dialogue (Italian) in a story 0-shot Language	100	100	100	100	100	100%
Character dialogue (Spanish) in a story 0-shot Language	100	100	100	100	100	100%
91.26%

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	100	100	100	100	100	100	100	96	100%
Write sentences with 10 words each 0-shot Rule following	100	100	95	94	86	83	79	76	42	41	80%
Write sentences with 20 words each 0-shot Rule following	100	100	100	100	100	100	80	80	74	14	85%
87.95%

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	100	100%
Count scenes 0-shot ToolingUtility	100	100	100	100	100	100	100	0	0	0	70%
outline-count											90.00%
pov-count
Count point of views for Jack and Olivia 0-shot ToolingUtility	100	100	100	100	100	50	50	50	50	50	75%
Count point of views for Jack Harper 0-shot ToolingUtility	100	100	100	100	100	100	100	100	100	0	90%
Count point of views for Olivia 0-shot ToolingUtility	100	100	100	100	0	0	0	0	0	0	40%
pov-count											68.33%
79.17%

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	100	100	100	100	100	100	100	100	100	67	97%
96.67%

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	100	100	100	100	100	100	0	0	80%
Simple 0-shot Utility	100	100	100	100	100	100	100	100	100	0	90%
Simple (1-shot) 1-shot Utility	100	100	100	100	100	100	100	100	100	100	100%
Simple (5-shot) Few-shot Utility	100	100	100	100	100	100	100	100	100	100	100%
Unattributed dialogue 0-shot Utility	100	100	100	100	100	100	100	100	100	100	100%
94.00%

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	100	100	100	100	100%
50 sentence summary 0-shot Rule following	100	100	100	100	100	100	100	100	100	100	100%
sentences											100.00%
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	98	92	99%
50 word summary 0-shot Rule following	100	100	100	100	98	92	77	77	77	27	85%
100 word summary 0-shot Rule following	100	98	92	54	54	54	27	9	9	2	50%
200 word summary 0-shot Rule following	27	2	0	0	0	0	0	0	0	0	3%
words											67.35%
87.44%