# Oh Fax — agent skill

**Use when:** you must deliver a PDF to a United States or Canada fax number and need a delivery receipt (leases, court forms, insurance, tax paperwork when email is rejected).

**Do not use when:** destinations outside US/CA, inbound receive, or you only need email/SMS.

## Connect (MCP, preferred)

Remote streamable HTTP (no Oh Fax account for MPP pay):

`https://app.ohfax.com/mcp`

- Claude Code: `claude mcp add --transport http ohfax https://app.ohfax.com/mcp`
- Muse Code (`~/.config/muse/settings.json`):
  `{"schema_version":1,"mcp_servers":{"ohfax":{"transport":"streamable_http","url":"https://app.ohfax.com/mcp","mode":"optional"}}}`
- Cursor / Codex / other: add that URL as a remote MCP server.

## Flow

1. `quote_fax` — free; inputs `to` + `document_url` or `document_base64` → `quote_id`, pages, amount
2. `send_fax` — returns payment instructions (does not charge)
3. Pay HTTP 402 on `https://app.ohfax.com/pay` with an MPP-capable client (`mppx`, agent wallet). Binding amount = challenge, not a guess.
4. `get_fax_status` / `get_fax_receipt` until final

## Also

- OpenAPI / MPP discovery: https://app.ohfax.com/openapi.json
- Full agent guide: https://ohfax.com/llms.txt
- Human docs: https://ohfax.com/docs/mcp