How to Upload Files to Claude Projects

Uploading files to a Claude project adds them to the project's knowledge base, making their content available to every conversation inside that project. You do not have to paste text or re-upload files each time you start a new conversation. Claude reads from the project files automatically when they are relevant to the question.

Once files are uploaded, it is worth tracking which source each one came from and what role it plays in the project. fenbs stores links and context notes alongside the project work, so the team always knows where each file originated and why it was added.

How to add files to a project

Open the Claude project and look for a "Knowledge" section, a paperclip icon, or an "Add content" option in the project settings or sidebar. The exact interface varies by version; check the Anthropic help center↗ (opens in a new tab) if the option is not immediately visible. Clicking it typically opens a file picker or a drag-and-drop area where you can select files from your computer.

On desktop, dragging files directly from a folder into the upload area usually works as well. Each file is processed after upload; a status indicator shows when processing is complete. A file that is still processing cannot be referenced in conversations yet.

Supported file types

Claude Projects accepts text-based files including PDFs, plain text files, and various document formats. Files that are primarily images—scanned PDFs with no selectable text, for example—may not index as well as text-based documents because there is less readable content for Claude to draw on.

For specific format support and current size limits, the Anthropic help center is the most reliable source. Supported formats and per-file or per-project limits can change with product updates. If a file type you need is not supported, extracting the text and saving it as a plain text or Markdown file is a reliable workaround.

How to handle folders and ZIP files

Claude Projects does not support uploading a folder or a ZIP archive as a single unit. If you want to add many files at once, the approach is to extract or prepare them first and upload individual files. On most operating systems, selecting multiple files in a file picker and uploading them together is faster than one at a time, even if ZIP upload is not supported.

For a folder with a large number of files, consider which files Claude actually needs. Adding a hundred files when ten are relevant dilutes the knowledge base. Start with the most directly relevant documents and add more if the project needs them. There is usually a per-project file limit; check the Anthropic help center for the current number.

If you are using Claude to work with code files or configuration files, the Claude.md file explains a different approach: a text file that provides structure and context rather than raw file uploads. For complex codebases, that approach is often more efficient than uploading individual files to a project.

Keep track of source links

Uploaded files do not carry a record of where they came from. Six months after uploading a PDF, it may not be obvious which version of a document it represents, who shared it, or whether a newer version exists. Keeping source links with the project work—either in a document, a task note, or a dedicated tool—prevents that confusion.

If a file needs replacing because a newer version is available, having the source link means finding the update is fast. fenbs keeps a Links and listings section alongside tasks and decisions, so the origin of each file is part of the project record rather than buried in email or chat history.

Update and remove files

To update a file, remove the old version from the knowledge base and upload the new one. Claude will stop drawing on the old file immediately after removal. For a project with several files, removing and re-uploading the changed file takes less time than recreating the entire project.

Files that are no longer relevant should be removed rather than left in place. An outdated specification sitting in a knowledge base can cause Claude to give answers based on superseded information. Keeping the file list current is part of keeping the project useful. For more on managing a Claude project over time, how to organize Claude Projects covers the upkeep side.

How to do this with fenbs

1. Create a free account and add your project to fenbs alongside the Claude project.
2. For each file you upload to Claude Projects, add a Links entry in fenbs with the source URL or location, the date, and a note on what the file covers.
3. When a file is updated, record the change in fenbs: old version replaced, new source, and the date. This gives a simple history of the knowledge base.
4. Add context notes in fenbs when a file covers something Claude should interpret in a particular way—for example, a spec that applies to one part of the project only.
5. If the Claude project needs to be rebuilt, the fenbs record shows exactly which files to re-upload and where to find them.

fenbs does not connect to Claude Projects directly or sync files automatically. The value is in keeping a human-readable record of the knowledge base that travels with the project even if the Claude project is deleted or moved.