# Fax Monster — agent access (fax.monster)

## Summary
Fax Monster lets a human owner sign in (Google or email magic link), fund prepaid API credits, and issue API keys. AI agents send US faxes, rent private numbers, and read inbound PDFs via REST or MCP — same backend. A command-line package is coming soon (not published yet).

## Plans (humans)
- Fax only ($1.99 one-time): shared send number, up to 50 pages, no receive.
- Send & Receive Faxes ($4.99 per 30 days): dedicated US number, 100 send + 100 receive pages per period.
- Fax Monster Business ($19/month, month-to-month): dedicated number, 1,000 combined in+out pages per month, email delivery of inbound PDFs, REST API + webhooks + MCP included. API/MCP sends on Business use the monthly page bucket, not prepaid credits.

## Authentication
- Header: Authorization: Bearer fm_live_<secret>
- Keys are created at https://fax.monster/developers by a **human owner** with verified email.
- Agents must never create accounts or API keys via the API/MCP.
- All agent usage is billed and audited under the owner's user id.

## REST API
- Base: https://fax.monster/api/v1
- OpenAPI: https://fax.monster/api/v1/openapi.json
- Insufficient credits: HTTP 402 JSON with `topUpUrl` for a human checkout.

## MCP
- URL: https://fax.monster/mcp (Streamable HTTP)
- Same Bearer API key in request headers.
- MCP Registry id: monster.fax/fax-monster (reverse-DNS of fax.monster). Manifest (draft): https://fax.monster/server.json and https://fax.monster/.well-known/mcp/server.json. To publish: verify domain ownership via DNS TXT or HTTP under /.well-known per registry docs, then submit name monster.fax/fax-monster.
- Tools mirror REST: account_balance, create_top_up_link, send_fax, get_fax_status, list_sent_faxes, rent_private_number, list_private_numbers, renew_private_number, release_private_number, list_inbound_faxes, download_inbound_fax, set_webhook.

## CLI
- npm package `faxmonster` — coming soon. Use REST or MCP today.

## Credits & failures
- Shared-number send: $1.99 per fax (up to 50 pages); debited at send. Failed delivery does not count against page allowances; prepaid send debits are refunded on failure when not on an allowance order.
- Fax only ($1.99) consumer order: one free retry, then email hello@fax.monster for a cash refund if delivery still fails.
- Private number rental: $4.99 per 30 days; outbound on that rental uses page allowance without per-fax debit.
- Top-up via Stripe Checkout (one-time); owner completes payment in browser.

## Webhooks (optional)
- Owner sets URL via PUT /api/v1/webhook or MCP set_webhook.
- HMAC-SHA256 in X-FaxMonster-Signature: sha256=<hex> over raw JSON body.
- Events: fax.outbound.delivered, fax.outbound.failed, fax.inbound.received.

## Support
- Product: https://fax.monster
- Humans: hello@fax.monster
- Security: https://fax.monster/security