# PromptFax MCP server

Send a one-off fax from inside ChatGPT or Claude. Pay-per-use, $2-$4.50 per delivered fax.

## Links
- Registry page: https://www.getdrio.com/mcp/app-promptfax-promptfax

## Install
- Endpoint: https://promptfax.app/mcp
- Auth: Not captured

## Setup notes
- Remote endpoint: https://promptfax.app/mcp

## Tools
- start_session (Start PromptFax session) - Use this first when a user wants to send or price a fax. PromptFax is built for irregular, pay-per-use outbound faxing: every real send requires a user-reviewed quote and Stripe payment authorization before transmission. MCP clients should set hostType to identify their host: chatgpt, claude, browser, or other. When calling this from ChatGPT, set hostType to chatgpt so PromptFax uses the ChatGPT widget and file flow. In ChatGPT, this opens the PromptFax widget; after the widget is shown, let the widget handle file selection, destination entry, automatic quote creation, Stripe Checkout, and status tracking. If no document is attached, tell the user to attach a document in the widget. The widget does not provide a document preview step. Do not tell ChatGPT users to get a quote; after the widget has a document and valid destination, tell them to verify the price and use Pay & send when ready. For Claude and other MCP hosts that cannot pass files directly, use the agent-friendly hosted PromptFax session page to guide upload/review, request a quote, launch Stripe Checkout, and poll delivery status. Do not call get_quote, checkout, or send_fax for a ChatGPT widget session unless the user explicitly asks for fallback behavior or the widget is unavailable. Use get_status only for a textual status refresh. Endpoint: https://promptfax.app/mcp
- attach_document (Attach fax document) - Fallback/non-widget tool for binding a PromptFax document or one or more HTTPS PDF URLs into the current MCP session before requesting a quote. In ChatGPT widget sessions, prefer the widget's file controls after start_session instead of calling this tool unless the widget is unavailable or the user explicitly asks for fallback behavior. Endpoint: https://promptfax.app/mcp
- get_quote (Get fax quote) - Fallback/non-widget tool for creating a user-reviewable pay-per-use fax quote when you have a fax number and either an MCP session, a PromptFax documentId, or one or more HTTPS PDF URLs. A quote is required before Stripe Checkout and before any real fax transmission. In ChatGPT widget sessions, do not call this after start_session because the widget auto-quotes once the document and destination are ready. Endpoint: https://promptfax.app/mcp
- checkout (Open Stripe Checkout) - Fallback/non-widget tool for starting external Stripe Checkout after the user accepts a pay-per-use quote. Payment authorization is required before PromptFax can send; PromptFax treats webhook-confirmed authorization, not browser redirect, as payment truth. In ChatGPT widget sessions, do not call this after start_session because the widget's Pay & send step opens Checkout. Endpoint: https://promptfax.app/mcp
- send_fax (Send paid fax) - Fallback/non-widget tool for sending after payment is authorized and the user explicitly wants to send now. In ChatGPT widget sessions, do not call this after start_session unless the widget is unavailable or the user explicitly asks for fallback behavior. Endpoint: https://promptfax.app/mcp
- get_status (Get fax status) - Use this when you need the latest PromptFax workflow state, quote/payment state, or fax transmission status. Endpoint: https://promptfax.app/mcp
- retry_failed_fax (Retry failed fax) - Use this after a retry-eligible failed fax to prepare a new authorization attempt. Endpoint: https://promptfax.app/mcp
- cancel (Cancel fax send) - Use this when you need to cancel the active PromptFax send. Endpoint: https://promptfax.app/mcp

## Resources
Not captured

## Prompts
Not captured

## Metadata
- Owner: app.promptfax
- Version: 0.1.0
- Runtime: Streamable Http
- Transports: HTTP
- License: Not captured
- Language: Not captured
- Stars: Not captured
- Updated: May 30, 2026
- Source: https://registry.modelcontextprotocol.io