PromptFax

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app.promptfax/promptfaxv0.1.0 Domain verified

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

Communication

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https://promptfax.app/mcp

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attach_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.

sessionIdstring, required

PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.

fileUrlsarray

One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow.

documentIdstring

PromptFax document identifier created by a prior upload or hosted session.

This tool isn't marked read-only, so it may change something on the server or in an account you connected.

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Tools (8)

attach_document

Argument	Type	Description
fileUrls	array	One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow.
sessionId*	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
documentId	string	PromptFax document identifier created by a prior upload or hosted session.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "sessionId"
  ],
  "properties": {
    "fileUrls": {
      "type": "array",
      "items": {
        "type": "string",
        "format": "uri"
      },
      "maxItems": 5,
      "minItems": 1,
      "description": "One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow."
    },
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "documentId": {
      "type": "string",
      "description": "PromptFax document identifier created by a prior upload or hosted session."
    }
  }
}

cancel

Use this when you need to cancel the active PromptFax send.

destructive

Argument	Type	Description
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
sendIntentId	string	PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "sendIntentId": {
      "type": "string",
      "description": "PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations."
    }
  }
}

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.

Argument	Type	Description
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
sendIntentId	string	PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
autoSendAfterAuthorization	boolean	When true, PromptFax sends automatically after Stripe confirms payment authorization. When false, call send_fax after authorization.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "sendIntentId": {
      "type": "string",
      "description": "PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations."
    },
    "autoSendAfterAuthorization": {
      "type": "boolean",
      "description": "When true, PromptFax sends automatically after Stripe confirms payment authorization. When false, call send_fax after authorization."
    }
  }
}

get_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.

Argument	Type	Description
fileUrls	array	One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow.
faxNumber	string	Destination US fax number. Accepts common human formats such as 415-555-0182 or E.164 format such as +14155550182.
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
documentId	string	PromptFax document identifier created by a prior upload or hosted session.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "fileUrls": {
      "type": "array",
      "items": {
        "type": "string",
        "format": "uri"
      },
      "maxItems": 5,
      "minItems": 1,
      "description": "One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow."
    },
    "faxNumber": {
      "type": "string",
      "description": "Destination US fax number. Accepts common human formats such as 415-555-0182 or E.164 format such as +14155550182."
    },
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "documentId": {
      "type": "string",
      "description": "PromptFax document identifier created by a prior upload or hosted session."
    }
  }
}

get_status

Use this when you need the latest PromptFax workflow state, quote/payment state, or fax transmission status.

read-only

Argument	Type	Description
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
sendIntentId	string	PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "sendIntentId": {
      "type": "string",
      "description": "PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations."
    }
  }
}

retry_failed_fax

Use this after a retry-eligible failed fax to queue another attempt under the existing authorization. You may supply a corrected destination.

Argument	Type	Description
faxNumber	string	Optional corrected US fax number for this attempt.
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
sendIntentId	string	PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "faxNumber": {
      "type": "string",
      "description": "Optional corrected US fax number for this attempt."
    },
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "sendIntentId": {
      "type": "string",
      "description": "PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations."
    }
  }
}

send_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.

destructive

Argument	Type	Description
sessionId	string	PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
sendIntentId	string	PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.

Input schema (JSON)

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "sessionId": {
      "type": "string",
      "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow."
    },
    "sendIntentId": {
      "type": "string",
      "description": "PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations."
    }
  }
}

start_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. 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.

Argument	Type	Description
files	array	Optional host-supplied files for initial attachment. ChatGPT file parameters include files[].download_url and files[].file_id.
hostType	string	Identify the MCP host so PromptFax can choose the right interaction mode. Use chatgpt for ChatGPT, claude for Claude, browser for a browser-hosted app, or other for unknown clients.
metadata	object	Optional host-specific metadata for diagnostics or session continuity.
faxNumber

{ "type": "object", "$schema": "http://json-schema.org/draft-07/schema#", "properties": { "files": { "type": "array", "items": { "type": "object", "properties": { "url": { "type": "string", "format": "uri", "description": "Temporary HTTPS download URL for a host-supplied file. PromptFax can fetch this URL to attach the document." }, "fileId": { "type": "string", "description": "Host-specific file identifier. This is useful for display or diagnostics, but PromptFax can only fetch files when a download URL is also supplied." }, "file_id": { "type": "string", "description": "Host-specific file identifier. This is useful for display or diagnostics, but PromptFax can only fetch files when a download URL is also supplied." }, "fileName": { "type": "string", "description": "Original filename reported by the host, used to help the user confirm the selected document." }, "mimeType": { "type": "string", "description": "MIME type reported by the host, such as application/pdf or image/png." }, "file_name": { "type": "string", "description": "Original filename reported by the host, used to help the user confirm the selected document." }, "mime_type": { "type": "string", "description": "MIME type reported by the host, such as application/pdf or image/png." }, "downloadUrl": { "type": "string", "format": "uri", "description": "Temporary HTTPS download URL for a host-supplied file. PromptFax can fetch this URL to attach the document." }, "download_url": { "type": "string", "format": "uri", "description": "Temporary HTTPS download URL for a host-supplied file. PromptFax can fetch this URL to attach the document." } }, "additionalProperties": {} }, "maxItems": 5, "description": "Optional host-supplied files for initial attachment. ChatGPT file parameters include files[].download_url and files[].file_id." }, "hostType": { "type": "string", "description": "Identify the MCP host so PromptFax can choose the right interaction mode. Use chatgpt for ChatGPT, claude for Claude, browser for a browser-hosted app, or other for unknown clients." }, "metadata": { "type": "object", "description": "Optional host-specific metadata for diagnostics or session continuity.", "propertyNames": { "type": "string" }, "additionalProperties": {} }, "faxNumber": { "type": "string", "description": "Destination US fax number. Accepts common human formats such as 415-555-0182 or E.164 format such as +14155550182." }, "sessionId": { "type": "string", "description": "PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow." }, "hostCapabilities": { "type": "object", "description": "Optional host capability hints, such as whether the client supports widgets, file-picking, hosted links, or other interactive surfaces.", "propertyNames": { "type": "string" }, "additionalProperties": {} } } }