PromptFax is a pay-per-use remote MCP server that lets an AI assistant send a real fax to a US fax number. Your assistant uploads a PDF or image, enters the destination, reviews a quote, opens Stripe Checkout, and queues the transmission. Pricing is $2.00 for the first 5 pages, then $0.10 per page after that, capped at $4.50 for up to 35 pages. Payment is captured only after the fax is recorded as delivered. There is no PromptFax account, no subscription, and no API key to manage. PromptFax uses OAuth and Streamable HTTP, so users install once and their assistant can start a fax workflow when needed. Inside ChatGPT, PromptFax opens a connector widget that handles document review, destination entry, Stripe Checkout, and the delivery report. Inside Claude or other MCP hosts, PromptFax falls back to an agent-friendly hosted session page that handles the same flow without requiring the host to pass files directly. Every real send requires a user-reviewed quote and Stripe authorization. The assistant cannot silently complete a fax. The `send_fax` and `cancel` tools are marked as destructive so well-behaved MCP hosts can surface confirmation steps. ## Capabilities - Send outbound faxes to US fax numbers - Attach a PDF or image from the host, widget, hosted session page, or HTTPS URL - Generate a pay-per-use quote before payment - Open Stripe Checkout for payment authorization - Queue a paid fax for transmission - Check workflow, payment, and delivery status - Retry eligible failed faxes - Cancel an active send while cancellation is still possible ## Tools - `start_session` — Create or resume a PromptFax MCP session. - `attach_document` — Bind a PromptFax document or HTTPS PDF URLs to an MCP session. - `get_quote` — Create a fax quote from a session, document, or HTTPS PDF URL. - `checkout` — Open Stripe Checkout after the user accepts a quote. - `send_fax` — Queue a paid fax for transmission. - `get_status` — Fetch workflow, payment, and transmission status. - `retry_failed_fax` — Prepare a retry flow after a retry-eligible failed fax. - `cancel` — Cancel the active send while cancellation is still possible. ## Common use cases - Sending a one-off medical record, referral, or intake form to a clinic's fax line. - Returning a signed contract to a small business or law office that still operates by fax. - Sending insurance claim forms, prior-authorization paperwork, or appeal letters. - Sending a benefits or HR form to a payroll vendor that requires fax submission. - Sending court filings or notarized documents to a filing office. ## Data handling PromptFax does not require an email address, does not provision a PromptFax account, and stores uploaded documents only as long as the fax workflow needs them. Server-side working copies are deleted after transmission. The browser-local delivery report persists for up to 24 hours unless cleared sooner. PromptFax is outbound-only and currently supports US fax numbers only. Payments are processed by Stripe for Cogint Labs LLC. ## Links - Homepage: https://promptfax.app/ - MCP endpoint: https://promptfax.app/mcp - Setup docs: https://promptfax.app/mcp-setup - Tool catalog: https://promptfax.app/mcp-tools - Demo: https://promptfax.app/mcp-demo - Pricing: https://promptfax.app/pricing - Privacy: https://promptfax.app/privacy - Terms: https://promptfax.app/terms
MCP readiness
Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here C+, 70.0/100), which weighs availability, conformance, p95 speed and descriptor. How the two differ
| Valid MCP handshake | 10/10 | initialize and tools/list both answered. |
| Live MCP endpoint | 24/25 | Endpoint answers the MCP initialize handshake (4264 ms); slow response -1. |
| Protocol revision | 8/10 | Speaks MCP 2025-11-25, 1 revision(s) behind 2026-07-28. |
| Signed descriptor | n/a | No MCP standard defines a signed server descriptor. |
| Uptime (30 days) | 15/15 | 30/30 probes succeeded over 30 days (100%). |
| Tool declaration | 10/10 | Lists 8 tool(s) with descriptions. |
| Verified identity | 5/10 | Publisher declared (repository, package or homepage); claim this listing to verify domain control. |
| Freshness + modern flags | 4/5 | seen in a source within 7 days. |
| Auth declaration | 2/5 | Declares credential scheme: smithery_api_key. |
Compared with peers
Against 53,039 reachable MCP servers in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.
- Readiness
- Higher than 88% of peers
- This listing 87 · peer median 81
- Latency
- Faster than 35% of peers
- This listing 464 ms · peer median 326 ms
Where it loses the most points, and how to win them back
- Verified identity −5
— Claim the listing and prove control of its domain.
Now: Publisher declared (repository, package or homepage); claim this listing to verify domain control.
- Auth declaration −3
— State how to authenticate (an auth scheme, or that none is needed).
Now: Declares credential scheme: smithery_api_key.
- Protocol revision −2
— Support the current protocol revision.
Now: Speaks MCP 2025-11-25, 1 revision(s) behind 2026-07-28.
Listed in
Directories this entry was found in.
How to connect
https://server.smithery.ai/promptfax/promptfax/mcpcurl -X POST https://server.smithery.ai/promptfax/promptfax/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'