Which Gmail search finds invoices with a PDF?

Try invoice has:attachment filename:pdf. Add newer_than:90d for the last three months or from: to limit it to one sender.

Can the assistant read the PDF itself?

Not through Nickbox. It reads the message as plain text and lists attachments without opening them, so amounts inside a PDF are not visible to it. Amounts written in the email body or the snippet are.

Will it download or save my invoices?

No. Nickbox only searches and reads. You open each message in Gmail to download the file.

Do these operators work in every inbox?

They are standard Gmail search operators, so they work in any Gmail or Google Workspace inbox. Category tabs depend on whether you use them in that inbox.

How do I find every invoice across all my Gmail accounts?

Ask your assistant to search every connected inbox with a Gmail query such as invoice has:attachment filename:pdf newer_than:90d, and to list sender, date and inbox for each hit. A read-only server like Nickbox runs the same query across up to 5 Gmail inboxes and returns headers and snippets. You then open the messages that matter.

Which Gmail search operators work for invoices?

The operators from Gmail's own search help cover most invoice hunts: has:attachment, filename:, from:, subject:, newer_than:, older_than:, category: and label:. They can be combined, and Nickbox passes your query to Gmail as written, with a limit of 500 characters.

Operator	What it does	Example
`has:attachment`	Messages with a file attached	`invoice has:attachment`
`filename:`	Attachment type or name	`filename:pdf`
`from:`	Sender	`from:billing@vendor.com`
`subject:`	Words in the subject	`subject:(invoice OR receipt)`
`newer_than:` / `older_than:`	Relative age, with d, m or y	`newer_than:90d`
`category:`	Inbox tab, such as purchases or updates	`category:purchases`
`label:`	One of your labels	`label:clients`

Gmail's help lists purchases among the category values. Whether it fills with invoices depends on how Gmail sorted your mail, so use it as a filter to try, not as a guarantee.

How do I ask an assistant to search all my inboxes for invoices?

Name the inboxes, give a time range and say what you want back. The assistant then calls search_all_accounts, which runs one query on the inboxes you list, and groups results by inbox. A first prompt that works well:

"Which accounts do you see?" This confirms your nicknames.
"Search all my accounts for invoice has:attachment filename:pdf newer_than:90d. List sender, subject, date and inbox, newest first."
"Show only the ones from billing and work."
"Read the top three and tell me the amount and due date if the email says them."

More prompts by situation are in prompts to search all your inboxes.

What prompts find specific kinds of invoices?

Pick the prompt closest to your problem and swap in your nicknames and vendors.

Everything from one vendor: "Search all my accounts for from:vendor.com has:attachment since January and group by month."
A client's invoices: "In acme, find messages with subject:invoice that have a PDF, and list which month each covers."
Missing months: "Search billing for invoices from from:hosting.com. Which months of 2026 have no invoice?"
Receipts for expenses: "Search all my accounts for receipt OR recibo newer_than:30d has:attachment and list vendor and date."
Old invoices: "Find invoices in work with older_than:1y filename:pdf and tell me which vendors appear."

For the missing-months prompt, check the answer against the actual list. The assistant sees only what the search returns.

What are the limits when searching for invoices?

The assistant sees message headers, snippets and plain text. Nickbox lists attachments but does not open them, so the number inside a PDF is out of reach. Invoices sent as a link to a portal have no attachment and will not match has:attachment.

Other limits to expect:

Results come in pages, and the assistant may stop early. Ask it to continue or to narrow the range.
The assistant can misread a long thread. Verify any amount or date in Gmail before you pay or file.
Nickbox cannot forward, label or move messages, because its permission is read-only. To save an invoice, open the message and download the file yourself.

How does this change if I invoice in Mexico?

In Mexico, a CFDI invoice usually arrives as two attachments: an XML file and a PDF. A useful search is has:attachment filename:xml, which catches the XML even when the PDF is missing. Run filename:pdf next to it to see which messages carry both.

Some Mexican supplier manuals describe sending the original PDF and XML in each email, one CFDI per email, though each issuer decides what it sends. Treat that as common practice. For tax questions, such as which document is valid for a deduction, ask your accountant. The assistant can help you find the files, and it should not decide what counts for the SAT. The Spanish version of this guide has Mexico prompts: encontrar facturas en todas tus cuentas de Gmail.

How do I set this up?

Connect each inbox to Nickbox, give it a nickname and paste one MCP URL into your assistant. The steps for Claude, ChatGPT and Cursor are in the docs. Nickbox is in a limited beta, it requests only the read-only Gmail permission and it does not store message content. See the security page for details and the pricing page for the plan: US$5 a month or US$48 a year, with a 7-day trial that needs a card.