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Context Files are files attached to a session that give Brunel’s AI the background knowledge it needs to plan accurately. They are the single biggest lever for improving plan quality and, by extension, the accuracy of your coding agent’s output.

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Why Context Files Matter

Without context, the AI plans in a vacuum — it makes assumptions about your architecture, naming conventions, and existing services that may be completely wrong for your codebase. With the right context files attached, it plans with the same background knowledge a senior developer would have. A plan built with context files will:
  • Reference existing services and patterns correctly instead of suggesting new ones
  • Respect your team’s coding conventions and style
  • Identify real dependencies rather than theoretical ones
  • Produce an export that a coding agent can execute accurately on the first attempt

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Attaching Files to a Session

  1. Open a session and click the File panel icon (usually in the right sidebar or bottom toolbar)
  2. Click Upload or drag and drop files into the panel
  3. Files are uploaded to the cloud and attached to this session immediately
  4. The AI will have access to all attached files in subsequent messages
You can also attach files directly in the chat input using the attachment button — both methods add files to the same session Context Files.

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The File Panel

The file panel (right side of the session) has two tabs: Both are shown in the same panel for easy access.

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Browsing and Previewing Files

Click any file to preview it inline. Brunel supports inline viewing for:
  • Plain text and Markdown — rendered directly in the panel
  • Code files — syntax-highlighted preview
  • Word documents (.docx) — inline document viewer
  • Spreadsheets (.xlsx) — inline spreadsheet viewer

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Planning Documents (Agent-Written Files)

As the planning agent works through your session, it writes structured documents to the Planning tab — business requirements, technical design, acceptance criteria, and more. These documents are the primary output you hand off to your coding agent. To export planning documents:
  • Download individually — click any file in the Planning tab to preview it, then use the download icon to save it locally
  • Download as ZIP — click the Archive icon in the Planning tab header to export all planning documents as a single ZIP file
When planning is complete, a Planning Complete banner appears in the chat. If planning documents are ready, you’ll see a Review Docs button — click it to open the planning documents directly.

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Removing Files

To remove a context file from a session, open the file panel, hover over the file, and click the remove icon. Removing a file detaches it from the session — it will no longer be included in the AI’s context for future messages.

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What Makes a Good Context File

The best context files are focused, accurate, and directly relevant to the task at hand.
You don’t need to attach your entire codebase. Focus on the files most relevant to the current task. A tight, relevant set of context files produces better plans than a large, noisy set.

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File Storage

Context files are stored securely in the cloud and associated with the session they were uploaded to. They persist as long as the session exists. If you archive a session, you’ll have the option to remove associated files to free up storage.