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PromptFax

by promptfax.app · remote · no sign-in to list tools · v0.1.0 · published by app.promptfax

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

Deletes · 2Changes · 4
CompareRegistry entry

8 tools: 2 can delete or cancel things, 4 change things and 2 only read.

Scanned Oct 21, 2026

No check matched anything in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http promptfax https://promptfax.app/mcp

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

8 tools

Deletes or cancels 2Claude Code: deny
  • cancelUse this when you need to cancel the active PromptFax send.No findings

    Why it is in this group

    • The name "cancel" says "cancel": a word for removing or ending something.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    Use this when you need to cancel the active PromptFax send.

    Annotations the server declares

    • destructiveHint: true
  • send_faxFallback/non-widget tool for sending after payment is authorized and the user explicitly wants to send now.No findings

    Why it is in this group

    • The name "send_fax" says "send": a word for sending, and what is sent cannot be taken back.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    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.

    Annotations the server declares

    • destructiveHint: true
Changes things 4Claude Code: ask
  • attach_documentFallback/non-widget tool for binding a PromptFax document or one or more HTTPS PDF URLs into the current MCP session before requesting a quote.No findings

    Why it is in this group

    • The name "attach_document" says "attach": a word for a change.
    Description, as the server wrote it
    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.

    Annotations the server declares

    • destructiveHint: false
    • openWorldHint: true
  • checkoutFallback/non-widget tool for starting external Stripe Checkout after the user accepts a pay-per-use quote.No findings

    Why it is in this group

    • The name "checkout" says "checkout": a word for a change.
    Description, as the server wrote it
    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.

    Annotations the server declares

    • destructiveHint: false
    • openWorldHint: true
  • retry_failed_faxUse this after a retry-eligible failed fax to queue another attempt under the existing authorization.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Use this after a retry-eligible failed fax to queue another attempt under the existing authorization. You may supply a corrected destination.

    Annotations the server declares

    • destructiveHint: false
    • openWorldHint: true
  • start_sessionUse this first when a user wants to send or price a fax.No findings

    Why it is in this group

    • The name "start_session" says "start": a word for a change.
    Description, as the server wrote it
    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. In ChatGPT, pass official files[] file parameters first when they are available so PromptFax can immediately import files[].download_url; never pass a raw file_id or local path as the document. The ChatGPT widget opens for destination entry, automatic quote creation, Stripe Checkout, status tracking, and Choose PDF from ChatGPT fallback when automatic attachment is unavailable or fails. 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. Standards-compatible MCP Apps hosts use the inline PromptFax picker, and text-only clients use the hosted PromptFax session page or attach_document with a fetchable HTTPS URL. 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.

    Annotations the server declares

    • destructiveHint: false
    • openWorldHint: true
Only reads 2Claude Code: allow
  • get_quoteFallback/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…No findings

    Why it is in this group

    • The name "get_quote" says "get": a word for reading.
    Description, as the server wrote it
    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.

    Annotations the server declares

    • destructiveHint: false
    • openWorldHint: true
  • get_statusUse this when you need the latest PromptFax workflow state, quote/payment state, or fax transmission status.No findings

    Why it is in this group

    • The name "get_status" says "get": a word for reading.
    Description, as the server wrote it
    Use this when you need the latest PromptFax workflow state, quote/payment state, or fax transmission status.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http promptfax https://promptfax.app/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__promptfax__get_quote",
      "mcp__promptfax__get_status"
    ],
    "ask": [
      "mcp__promptfax__start_session",
      "mcp__promptfax__attach_document",
      "mcp__promptfax__checkout",
      "mcp__promptfax__retry_failed_fax"
    ],
    "deny": [
      "mcp__promptfax__send_fax",
      "mcp__promptfax__cancel"
    ]
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as promptfax. Review it before you use it.