How to Upload Files (PDF, Excel, CSV) to an Agent or Workflow

Last updated: March 26, 2026

You can upload files directly in agent chat, through a workflow's file-handling nodes, or via the API. For agents, just attach the file in the chat window — the agent reads it automatically.

Upload a File in Agent Chat

This is the fastest way to get a file into Gumloop.

  • Open your agent chat.

  • Click the attachment icon (paperclip) at the bottom of the chat window.

    image.png

  • Select your file and send your message.

The agent automatically reads text-based files (PDF, Word, Excel, CSV, TXT, JSON, HTML) and parses it.

Large files (over ~32 MB)

Files above roughly 32 MB may exceed the LLM context limit. Instead of uploading directly:

  • Upload the file to Google Drive.

  • Add the Google Drive app under your agent's tools (if not already added).

    image.png

  • Paste the Drive link in the agent chat.

  • The agent will read the file from Drive without hitting the context limit. For a full walkthrough, see My Agent Can't Handle Large Files — What's the Workaround?

When your agent processes a file in chat, the contents are loaded directly into the LLM's context window (limit: ~32 MB). Files the agent fetches via tools into its Code Sandbox are processed as code, not context, and can be up to 300 MB.

For bulk file processing, upload your files to a Google Drive folder and send the folder link in agent chat.

Upload a File in a Workflow

To use a file in a workflow, upload it to a file-handling node:

  • Open your workflow in the editor.

  • Click the folder icon on any file-handling node (File Reader, PDF Reader, CSV Reader, etc.).

    image.png

  • In the file picker, click Pick a File to Upload.

    image.png

  • Select your file.

The file is stored in your Gumloop file storage and available for all future runs.

File-handling nodes

Node

Supports

Notes

File Reader

PDF, Word, Excel, CSV, TXT, HTML, JSON

Outputs plain text content

PDF Reader

PDF only

Three modes: Standard (free), Advanced (+5 credits), OCR (2–20 credits) for scanned docs

CSV Reader

CSV only

Outputs each column as a list; column headers must match exactly

Google Drive File Reader

Any Drive file

Outputs a file object — pass directly to File Reader or PDF Reader

Google Drive Folder Reader

Any Drive folder

Outputs a list of files; ideal for bulk processing

Upload Files via API

Use the API to upload files programmatically before triggering a workflow run.

Single file:

POST https://api.gumloop.com/api/v1/upload_file

Multiple files:

POST https://api.gumloop.com/api/v1/upload_files

Full reference: File Operations — Upload Files

Supported File Types and Size Limits

Supported types: .csv, .pdf, .doc, .docx, .xlsx, .xls, .json, .txt, .html

Upload method

Limit

Workflow file upload

200 MB per file

Agent Code Sandbox

300 MB

Still Need Help?

Reach out at support@gumloop.com or in the shared Slack channel.