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Send a fax from Antigravity CLI

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Antigravity CLI, Google's successor to Gemini CLI, can send and read faxes for you through the Fax for Agents tool server. You describe the fax in plain words. Antigravity prepares the page, gets a quote and sends it. By default it sends inside the limits your organization set, with no approval per fax. This guide was recorded in Sandbox mode, so nothing reached a real fax line.

Screenshots taken on .

Before you start

  • A Fax for Agents account. The dashboard is at app.faxforagents.com.
  • Antigravity CLI (the agy command) with the Fax for Agents tool server connected. Run agy mcp add faxforagents "https://mcp.faxforagents.com/mcp/?auth=required", then start agy, type /mcp, choose faxforagents and Authenticate. Allow the connection in the browser and paste the code back into the terminal. Keep the box "Let this app send faxes within your limits without asking" ticked.
  • The Connected apps switch in Settings is on by default. The default limits are $5.00 per fax and 20 faxes a day.

1.Open Antigravity CLI

Open Antigravity CLI in the folder you work in. The tool server is already connected, so you can start typing.

Antigravity CLI open in a terminal, in the demo folder, waiting for a prompt.
Open Antigravity CLI in your project folder. Fax for Agents is connected as a tool server.

2.Check the tool server

Type /mcp when you want to see the connection.

The /mcp panel lists faxforagents as Authed with its tools: get_guide, get_fax_capabilities, prepare_fax, get_fax_document, quote_fax and more.
The panel lists faxforagents as Authed with its tools. Esc closes it.

3.Allow the fax tool

Type what the fax should say and where it goes. Antigravity asks once before it runs a tool.

Antigravity CLI asks Allow calling this tool? for faxforagents/prepare_fax, with the option Yes, and always allow tool in this conversation.
Choose "Yes, and always allow tool 'faxforagents/prepare_fax' in this conversation". Antigravity stops asking for that tool. It asks the same way once for each new tool.

4.Read the quote

Antigravity prepares a one page document from your words and asks for a quote. Nothing is sent yet.

Antigravity shows the quote: one page to +15550000001, $0.000 in Sandbox, Quote State allowed.
The quote shows the destination, the pages, the price and the line "Quote State: allowed".

5.Send it

Say "Send it." The send goes through at once because the quote is inside your limits.

Antigravity reports the fax as delivered, Pages Delivered 1 of 1 page, with the fax id and the quote id.
Antigravity reports "State: delivered" with the fax id.

6.Check the evidence

Ask for the delivery evidence when you want the full record.

The delivery evidence: fax id, attempt id, state delivered, provider reference, remote station SBX-OK, pages delivered, duration and the time completed.
The evidence lists the attempt, the provider reference, the remote station SBX-OK, the pages delivered and the time the fax completed.

7.Read the inbox

Received faxes work the same way. Ask for your inbox.

Antigravity lists the inbox and prints the text of the newest received fax from +15550000042, two pages.
Antigravity lists the received faxes and reads the newest one as text.

What the limits mean

Open Settings in the dashboard. The Connected apps card holds the switch "Let connected apps send without asking". Under it are two fields, "Amount per fax, at most" ($5.00) and "Faxes per day" (20). Apps like Antigravity CLI send inside these limits with no approval per fax. Turn the switch off and every send waits for a person. Finer limits, such as destinations or one app only, live under Policies. See the guide Your assistant sends within limits by default.

Approve every fax instead

  1. In Settings, turn off "Let connected apps send without asking" and choose Save.
  2. Ask Antigravity to quote the fax. The quote says approval is required.
  3. Say "Ask a person to approve it." A person approves in the dashboard or with the ffa command line, then you tell Antigravity to send.

The full routine is in Approve every fax from Antigravity CLI.

Troubleshooting

  • The quote says "deny" or "approval required" although you expect a plain send. An owner turned the Connected apps switch off, or the fax is above a limit. Check Settings, Connected apps for your environment.
  • Antigravity asks "Allow calling this tool?" before each new tool. That is Antigravity's own permission prompt. Choose "Yes, allow tool call", or the "always allow tool" option for this conversation.
  • Antigravity asks "Run this command?" and wants to list files instead of using the fax tools. Choose "No, cancel" and add an AGENTS.md to the folder that says fax tasks use the faxforagents tools.
  • /mcp shows faxforagents with "Unauthorized [Auth Needed]". Choose the server, then Authenticate, allow the connection in the browser and paste the code back.

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