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PromptFax

app.promptfax/promptfax

This connects Claude or ChatGPT to PromptFax's fax delivery service, letting you send actual faxes without leaving your chat session. You'd reach for this when you need to file something with a government office, send documents to a medical provider, or hit any other institution that still requires faxed submissions. It's pay per use at $2 to $4.50 per delivered fax, so you're not paying for a subscription to handle occasional fax requirements. The server exposes fax sending operations through a streamable HTTP transport, handling the conversion and delivery while you stay in your workflow.

tools
8
transport
HTTP
last updated
May 30, 2026
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Install

From registry metadata
$ npx add-mcp https://promptfax.app/mcp --name promptfax

Run in your terminal. add-mcp asks which agents to add it to (Claude Code, Codex, Cursor and more). Add -g to install it for every project.

Review the command, arguments and environment values before installing. MCP servers run with your local permissions.

Other ways

Claude Code

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

Run in your terminal. Add --scope user to make it available in every project.

Tools

Verified live · 8 tools

Verified live against the running server on Nov 6, 2026.

start_sessionUse 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:...6 params

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:...

Parameters* required
faxNumberstring
Destination US fax number. Accepts common human formats such as 415-555-0182 or E.164 format such as +14155550182.
filesarray
Optional host-supplied files for initial attachment. ChatGPT file parameters include files[].download_url and files[].file_id.
hostCapabilitiesobject
Optional host capability hints, such as whether the client supports widgets, file-picking, hosted links, or other interactive surfaces.
hostTypestring
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.
metadataobject
Optional host-specific metadata for diagnostics or session continuity.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
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. In ChatGPT widget sessions, prefer the widget's file controls after start_session instead of calling this tool unless the widget is u...3 params

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 u...

Parameters* required
documentIdstring
PromptFax document identifier created by a prior upload or hosted session.
fileUrlsarray
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.
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 URLs. A quote is required before Stripe Checkout and before any real fax transmission. In ChatGP...4 params

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 ChatGP...

Parameters* required
documentIdstring
PromptFax document identifier created by a prior upload or hosted session.
faxNumberstring
Destination US fax number. Accepts common human formats such as 415-555-0182 or E.164 format such as +14155550182.
fileUrlsarray
One or more HTTPS URLs for PDF or image documents that PromptFax should attach to the fax workflow.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
checkoutFallback/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 s...3 params

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 s...

Parameters* required
autoSendAfterAuthorizationboolean
When true, PromptFax sends automatically after Stripe confirms payment authorization. When false, call send_fax after authorization.
sendIntentIdstring
PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
send_faxFallback/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.2 params

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.

Parameters* required
sendIntentIdstring
PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
get_statusUse this when you need the latest PromptFax workflow state, quote/payment state, or fax transmission status.2 params

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

Parameters* required
sendIntentIdstring
PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
retry_failed_faxUse this after a retry-eligible failed fax to queue another attempt under the existing authorization. You may supply a corrected destination.3 params

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

Parameters* required
faxNumberstring
Optional corrected US fax number for this attempt.
sendIntentIdstring
PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.
cancelUse this when you need to cancel the active PromptFax send.2 params

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

Parameters* required
sendIntentIdstring
PromptFax send intent identifier returned by get_quote or session status. Use this for checkout, send, status, retry, or cancel operations.
sessionIdstring
PromptFax MCP session identifier returned by start_session. Use this to continue a session-backed fax workflow.

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Details

Transport
HTTP
Registry
MCP registry, active
Resources
2
Tools verified
Nov 6, 2026