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Fusion

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Fusion excels at coherent text processing across massive contexts.

OpenrouterLanguage ModelsClosed
Model page Updated 2026-06-14

About Fusion

Fusion is a closed-weight large language model offered exclusively through the Openrouter platform. Its architecture supports text-only interactions and maintains context across up to 128000 tokens without requiring users to manage model weights directly.

The design emphasizes stability for lengthy inputs, making it suitable for tasks such as document analysis, multi-turn dialogue, and content synthesis. Typical usage includes research assistance, creative writing support, and summarization workflows where preserving earlier context is essential.

Capabilities

Long-context reasoning
Text generation
Instruction following
Document summarization
Question answering
Multi-turn dialogue

Best for

Long Document Analysis

Fusion handles 128k token inputs for summarizing extensive reports or research papers while preserving details across distant sections.

Interactive AI Assistants

Its instruction following and multi-turn dialogue strengths support building chat systems that maintain context over extended conversations.

Large-Scale Question Answering

The model applies long-context reasoning to answer queries drawn from books, codebases, or datasets spanning many pages.

Strengths & limitations

Strengths

  • +Large 128k token context window
  • +Broad text task versatility
  • +OpenRouter platform access

Limitations

  • Text modality only
  • No vision or multimodal input
  • Standard LLM hallucination risks

Where to access Fusion

Frequently asked questions

Fusion supports a context window of 128000 tokens.

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