> ## Documentation Index
> Fetch the complete documentation index at: https://docs.overcontrolgroup.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Chat modes

> Choose Fast, Expert, or Vision to match the way you want to work.

[OverControl Chat](https://chat.overcontrolgroup.com) gives you three modes: **Fast**, **Expert**, and **Vision**. Choose a mode from the selector in Chat before sending your message. No API key or model configuration is needed.

| Mode | Best for | What to expect |
| - | - | - |
| **Fast** | Writing, summaries, explanations, and everyday questions | Direct responses without an extended reasoning step. This is the default mode. |
| **Expert** | Complex analysis, coding, planning, and multi-step problems | More reasoning before the final answer. Responses can take longer and use more of your allowance. |
| **Vision** | Screenshots, photographs, diagrams, and other images | Answers that use the visual content of supported image attachments. |

## Fast

Use **Fast** when you want to move quickly from a question to a useful result. It works well for rewriting messages, summarizing text, brainstorming, explaining concepts, and straightforward coding help.

```text theme={null}
Turn these notes into a concise project update.
Include progress, blockers, and next steps. Keep the tone professional.

[Paste your notes here]
```

Fast uses **Lume 3.5 Max** without extended reasoning. It can also work with supported text documents and PDFs after Chat extracts their text.

## Expert

Use **Expert** when a task has several steps, competing constraints, or details that need careful comparison. Give it the relevant context and ask for the reasoning or tradeoffs you need in the answer.

```text theme={null}
Review this implementation against the requirements below.
Identify correctness issues, explain their impact, and suggest the smallest useful fixes.

[Paste the requirements and code here]
```

Expert uses **Lume 3.5 Max** with deeper reasoning enabled. It can take longer than Fast. A more detailed reasoning process does not guarantee a correct answer, so check the result against your requirements.

## Vision

Use **Vision** when the information you need is visible in an image. Attach a supported JPEG, PNG, or WebP image, wait for the upload to finish, then send your question.

```text theme={null}
Explain the error shown in this screenshot.
Identify the relevant text and suggest what I should check first.
```

Vision uses **Lume Omni**. It can describe visual content, read legible text, and help interpret diagrams. Small text, blurry images, and precise measurements can be difficult to interpret. Crop to the relevant area and provide a clear image.

PDFs are processed as extracted text in Chat. Selecting Vision does not turn a scanned PDF into an image-based document analysis workflow. For visual pages, attach supported images of the relevant pages instead.

## Choose a mode for attachments

Use **Fast** for a short document summary, **Expert** for a detailed comparison or review, and **Vision** for image content. Attachments are limited to **3 files per message**, **5 MiB per file**, and **10 MiB combined**.

See [Files and images](https://docs.overcontrolgroup.com/chat/files-and-images.md) for supported formats and extraction limits. Chat's attachment support is separate from the API's multimodal capabilities; the mode selector does not enable audio uploads, web search, or code execution.

## Get a more useful answer

State the task, provide the relevant context, and ask for the format you want. Keep follow-ups in the same conversation when they depend on earlier messages. Start a new chat for an unrelated task.

Chat uses your OverControl account allowance. Review usage in the [dashboard](https://app.overcontrolgroup.com/dashboard). Conversations are saved with a **30-day retention period**; see [Privacy and security](https://docs.overcontrolgroup.com/chat/privacy-security.md) before relying on Chat to keep important work.


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