Seed 1.8
2892°
ByteDance | 256,000 token context | $0.25/M input, $2.00/M output. Optimized specifically for multimodal agent scenarios. It features enhanced agent capabilities, upgraded multimodal comprehension, and more flexible context management.
Guides for this model
Open weights vs open source vs API-only: what you are actually allowed to do
How to choose an AI model in October 2026: the closed source news, then the open weights worth downloading
What is a GGUF file? Quantized models explained (Q4, Q8, fp8, NF4)
Captain's notes
Notes from 2026-10-13
Seed 1.8 is ByteDance's API-only model built specifically for multimodal agent workflows, combining vision understanding with enhanced tool-use and context management across a 256,000-token window. The input price is low; output is mid-range. If you are building agents that need to see and act rather than just chat, this is the use case it was designed for.
Known for
- Built from the ground up for multimodal agent scenarios, not retrofitted
- 256,000-token context window for long, multi-step agent sessions
- Handles both vision and text inputs within the same pipeline
- Flexible context management aimed at complex, multi-turn agent tasks
Watch out for
- API-only, closed weights — you cannot run this locally or inspect the model
- Output tokens at $2.00/M add up fast in agentic loops that generate verbose tool calls
- ByteDance has not published a model card, so capability limits are not independently documented
Prompts to try
Multimodal agent planning
You are an agent with access to a web browser and a file system. A user attaches a screenshot of a cluttered project dashboard. Identify the three most overdue tasks visible, propose a prioritised action plan, and describe exactly which tools you would call and in what order to update the task statuses.
Long-document reasoning chain
Here is a 200-page merger agreement. Identify every clause that could trigger a material adverse change termination right, summarise the conditions each one requires, and flag any that conflict with each other. Work through the document section by section and show your reasoning before giving the final list.
Vision-guided data extraction
Attach a photo of a printed invoice or receipt. Extract every line item, its quantity, unit price and total. Then calculate whether the subtotal, tax and grand total are arithmetically consistent, and flag any discrepancy with the exact figures involved.
Compare with
- Seed 2.0 proOpen-weights model256,000 token context · $0.50/M input, $3.00/M output
- GPT-6 LunaAPI-only model1,050,000 token context · $0.10/M input, $0.50/M output
- GPT-5.6 LunaAPI-only model1,050,000 token context · $0.20/M input, $1.20/M output
- Claude Opus 5.5API-only model1,000,000 token context · $4.00/M input, $20.00/M output
More text models from bytedance
Questions people ask
- Can I run Seed 1.8 locally?
- No. Seed 1.8 is API-only and ByteDance has not released the weights, so local deployment is not possible.
- What does Seed 1.8 cost and how long is its context?
- ByteDance prices it at $0.25 per million input tokens and $2.00 per million output tokens, with a 256,000-token context window.
- What makes Seed 1.8 different from a general-purpose model?
- ByteDance built it specifically for multimodal agent scenarios rather than general chat, with explicit focus on tool use, vision comprehension and managing long, multi-step contexts.
Captain's verdictA focused agent-and-vision model at a reasonable input price — worth evaluating if you are building pipelines, less compelling if you just need a chat assistant.
Captain writes these notes from the model's own description and model card. Prices and context sizes are the provider's at the time of writing and can change.
Ranking badge
Updated Oct 22, 2026
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How this score adds up
This model has no popularity data from any source yet, so it carries a stand-in number below 7,000° that keeps the lists complete. It never ranks above a model with data. The breakdown appears here as soon as a source reports it.
Glossary: the terms used here
- Heat score
- One number for how much a model is used and wanted right now, from 0° to 9,999°. Every list on this site that says hottest is sorted by it and nothing else.
- Floor
- The 7,000° every model with real data starts from. The scale runs from 0° to 9,999°; the part below the floor is reserved for stand-ins (models without data), so that a model with data always ranks above one without. The floor is the same for everyone and decides nothing; the degrees above it are the measurement.
- Download-equivalents
- Everything the score treats as a download, added up: downloads themselves, each torrent seeder as 1,000, each AI Horde image and each run on a generation site as one.
- Log scale
- Counting by tens, not by ones: going from 1,000 to 10,000 downloads adds the same degrees as going from 10,000 to 100,000. It keeps giants from crowding out everything else.
- Likes
- Thumbs up and likes from every source, worth half a download each on the log scale.
- Adoption rate
- How many downloads a day a model gets right now, from the difference between two readings of a source. A quarter of the weight of the download term.
- Measured and estimated
- Measured means two readings of a source exist and the difference is real. Estimated means only today's total is known and the past is spread over the model's life; the site says which one it is showing.
- Seeder
- Someone who keeps a copy of the weights online for others to download over a torrent, or a hosted mirror doing the same. Each one counts as 1,000 downloads.
- AI Horde
- A volunteer network that generates images for free on donated computers. The number of images it has made with a model is public, and each counts as one download.
- Generation sites
- Sites that host their own copies of a model and let people generate with it, such as PixAI, SeaArt and Yodayo. Their downloads count like Civitai's and each generation run as one download.
- OpenRouter tokens
- A text model served through an API, such as Claude or GPT, has no weights to download, so its usage is measured in tokens: the pieces of text it read and wrote through OpenRouter, a gateway many apps use, over the last 30 days. Every 10,000,000 tokens count as one download. Source: OpenRouter (openrouter.ai/rankings), CC BY 4.0.
- Full model (checkpoint)
- The weights themselves, the file that generates on its own. It gets a bonus because add-ons depend on it.
- LoRA and embedding
- Small add-on files that steer someone else's weights toward a style, a character or a concept. They cannot run alone.
- Family and weights
- The base a model is built on, such as SD 1.5, SDXL, Flux or Wan. Every model inherits the release date of its family's weights.
- Age
- Degrees taken off for how long ago the family's weights came out: 150° a year, up to 750°. It keeps old downloads that had years to pile up from freezing the top of the list.
- Family boost
- A small, bounded nudge for LoRAs of a family this site is pushing forward right now, always listed in the breakdown.
- Stand-in score
- A stable number below the floor given to a model no source reports on yet, so lists stay complete. It never ranks above a model with data.
- New! (grace period)
- A model less than 7 days old shows New! instead of a score and holds no place in the rankings. Its score is computed from day one, but a model one day old grows faster than anything, so without the wait the week's #1 would always be whatever came out yesterday rather than what held up for a week.
- Trend
- How a model's growth over a period compares with the typical model's growth over the same period. Faster than typical reads as a rise, slower as a fall.
- Typical model
- The middle of the catalog: half the models with a figure grew faster over the period, half slower.
Seed 1.8 is a text model for the Text / LLM family listed on ModelTrends.ai, a read-only catalog of open source AI image, video and text models. Compare it with other Text / LLM models and check its heat score to see how it is trending.
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