> ## Documentation Index > Fetch the complete documentation index at: https://docs.conversion.ai/llms.txt > Use this file to discover all available pages before exploring further. # Files and sandbox > What you can attach to a chat, and what Conversion AI can do with files in its sandbox. You can attach files to any message in a chat. Conversion AI also has its own **sandbox**: an isolated Linux environment it uses to read attachments, run scripts, and generate files for you to download. ## Uploading files Click the **+** button next to the chat input, or drag and drop files onto the chat. You can also paste an image straight from your clipboard. | Constraint | Limit | | ----------------- | ------------------------------------------------- | | Max file size | **5 MB per file** | | Files per message | No fixed limit (subject to the per-file size cap) | Files larger than 5 MB are rejected with an error notification. ### Supported file types Conversion AI reads file contents differently depending on the type: | Type | Examples | How it's handled | | ------------- | ---------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Images | JPEG, PNG, GIF, WebP | Conversion AI can see the image directly and answer questions about it. | | PDFs | `.pdf` | Conversion AI reads the document directly, including text and embedded images. | | Text files | `.txt`, `.csv`, `.tsv`, `.json`, `.xml`, `.yaml`, `.md`, `.html`, `.js`, `.ts`, `.sql`, and similar text formats | Conversion AI reads them as text. | | Anything else | `.xlsx`, `.zip`, etc. | The file is dropped from the message, but a copy stays in the sandbox at `/vercel/sandbox/uploads/`. Conversion AI can read or convert it from there using `bash` (for example, opening an `.xlsx` with a Python library). | Even when a file isn't supported as a direct attachment, you can still ask Conversion AI to work with it. It'll use the sandbox to read or convert it. ## The sandbox Behind the chat, Conversion AI has access to a **Linux sandbox** scoped to that chat. It uses the sandbox whenever a task needs actual computation, like parsing or generating a CSV, generating a chart, or building a downloadable report. ### What's in the sandbox | Capability | Notes | | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Persistent filesystem | Files created in one message are still there in the next message of the same chat. Different chats get different sandboxes. | | Bash shell | Conversion AI can run shell commands to inspect files, manipulate them, and run scripts. | | Python 3.12+ | With common packages like `pandas`, `numpy`, `matplotlib`, `openpyxl`, `requests`, `pyarrow`, and `jinja2`. Conversion AI can install additional well-known packages on demand. | | Node.js 20+ | Available for scripts that need it. | | Network access | Conversion AI can install packages and fetch resources from the web from within the sandbox. | ## Sharing files back to you When Conversion AI has a file ready for you (a converted CSV, a generated report, a chart image), it surfaces the file in the chat with view and download actions. You'll see it as a card in the conversation; no separate downloads page. ## What it's used for Typical tasks that use the sandbox: | Task | What happens | | ------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Convert a CSV to JSON (or any format) | Reads your upload, writes the converted file, shares it back. | | Summarize a long PDF | Conversion AI reads the PDF directly. No sandbox needed for read-only summaries. | | Build a downloadable report from your workspace data | Pulls data via [tool calls](/product-docs/conversion-ai/tool-calls), processes it in Python, writes a CSV or XLSX, and shares it back. | | Generate or transform an image before uploading it to your media library | Builds the image in the sandbox, then uses `upload_image_to_assets` to add it to your workspace's media library so it can be referenced in emails and forms. | ## What the sandbox can't do | Limitation | Notes | | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Reach your workspace data directly | The sandbox doesn't have a backdoor into Conversion. Conversion AI must use [tool calls](/product-docs/conversion-ai/tool-calls) to read or change anything in your workspace. | | Persist across chats | Each chat has its own sandbox. Files created in one chat are not available in another. | | Hold files indefinitely | The sandbox is not long-term storage. If you need a file kept, download it. |