Fill a form from a local file

Drive a browser form from a PDF or CSV file on your local machine.

Use this recipe when the data already lives on your machine, for example in a PDF resume or a CSV file, and the form lives in a browser on the same desktop. Cua Driver drives both, so the data never has to be uploaded anywhere because the agent reads it locally and types it into the form.

Before you start: install Cua Driver, grant host permissions, and connect your agent.

Put the source file on the machine#

Save the source file somewhere the desktop user can open it, for example:

~/Downloads/resume.pdf

Cua Driver has no filesystem read tool. The agent reads local files by opening them in an app it can see, for example Preview, another PDF viewer, or a text editor, then reading the on-screen content with the accessibility tree and screenshots from get_window_state.

For a CSV, open the file in a text editor, spreadsheet app, or browser tab. If the file contains many rows, start with one row and name the row or record the agent should use.

Give the agent the task#

In your MCP client, describe the local file, the fields to read, and the form URL:

Open ~/Downloads/resume.pdf in the PDF viewer. Read the name, email,
phone, and work history. Then open
https://form.jotform.com/<your-form-id> in the browser, fill each matching
field from the PDF, and submit the form.

The agent can use launch_app to open the PDF viewer, page to drive the browser, get_window_state or get_accessibility_tree to read visible fields, and click, type_text, or set_value to fill the form. get_window_state returns a screenshot alongside the tree by default, so the agent can ground on both.

Watch the field mapping#

Keep the browser visible while the agent maps source fields to form fields. If a form label is ambiguous, correct the mapping in plain language, for example "use the resume email for Work Email" or "leave Current Employer blank".

Forms vary, so the agent works best when you name the exact fields to fill, such as name, email, and phone, instead of asking it to fill the whole form.

Scale this out#

One desktop fills one form at a time. To submit many forms in parallel, for example one per CSV row or one per applicant, move the same workflow onto Cua Sandbox cloud desktops. Drop each source file into its own sandbox, start one agent job per sandbox, and fan the jobs out.

Use Run sandboxes in parallel to run many jobs concurrently. Use Choose and build a sandbox image to stage the source files in an image or mount them into each sandbox. Use Your first cloud sandbox for the basic SDK lifecycle.