What is the context window of Seed 1.6, and how long can its output be?

Seed 1.6 has a context window of 256K tokens (256,000), and its maximum output is 64K tokens (64,000).

Can Seed 1.6 read images, audio, video or PDFs?

No, Seed 1.6 accepts text only as its input modality, so it cannot read images, audio, video or PDFs.

Does Seed 1.6 support tool calling?

Yes, Seed 1.6 supports tool calling (function calling).

Does Seed 1.6 support structured output or JSON mode?

Yes, Seed 1.6 supports structured output (JSON schema or JSON mode).

Does Seed 1.6 have a reasoning or thinking mode?

Yes, Seed 1.6 supports a reasoning mode.

What are the closest alternatives to Seed 1.6?

Qwen3 VL Flash (Alibaba Cloud) by Alibaba, Composer 1 by Cursor and Qwen3 Max by Alibaba, matched on model kind and release date with no comparable price.

What is the best open-weight alternative to Seed 1.6?

Kimi K3, which holds rank 19 on Arena Text, is the highest-ranked open-weight model; Seed 1.6 itself is closed.

What is the difference between Seed 1.6 and Seed 1.6 Flash?

Both have a context window of 256K tokens (256,000). Seed 1.6 was released on October 15, 2025, while Seed 1.6 Flash was released on August 28, 2025.

Who made Seed 1.6 and when was it released?

Seed 1.6 was made by ByteDance and released on October 15, 2025.

Seed 1.6

ByteDance

Seed 1.6

Developer	ByteDance
Release date	October 15, 2025
Family	Seed
Generation	Seed 1.6
Context window	256K tokens
Max output	64K tokens
Input	Text
Output	Text
Weights	Closed
Successor	Seed 1.8
Website	bytedance.com

Part of a series on

ByteDance

Context: 256Ktokens
Released: 1y ago

ByteDance launched Seed-1.6-Embedding, an embedding model built on its Seed1.6-Flash base model. The launch announcement highlights multimodal hybrid retrieval and flexibility, with ByteDance claiming a 20.1-point lead over the second-place model on the MMEB_v2 video leaderboard. It is built for embedding and retrieval work, with training aimed at generalizing across niche scenarios and complex tasks.

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Additional source evidence

Source model: bytedance-seed/seed-1-6
Source family: seed
Last updated: 2025-10-15
Model context: 256K
Model output limit: 64K
Open weights: No
File attachments: Yes
Reasoning: Yes
Tool calling: Yes
Temperature control: Yes

Complete source record (JSON)

{
  "id": "bytedance-seed/seed-1-6",
  "name": "Seed 1.6",
  "description": "ByteDance Seed model for long-context reasoning, instruction following, and tool-assisted tasks",
  "family": "seed",
  "last_updated": "2025-10-15",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "temperature": true,
  "modalities": {
    "input": [
      "text",
      "image",
      "video"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 256000,
    "output": 64000
  },
  "release_date": "2025-10-15",
  "open_weights": false
}