Send a fax from Codex

Connect Codex to Oh Fax MCP to quote and send a PDF to the US or Canada.

Connect

Install the remote MCP server:

codex mcp add ohfax --url https://app.ohfax.com/mcp

Or add this to ~/.codex/config.toml:

[mcp_servers.ohfax]
url = "https://app.ohfax.com/mcp"

See the MCP documentation for tools and payment details. The endpoint is https://app.ohfax.com/mcp using streamable HTTP.

Steps

1. Configure the MCP connection using the setup above.
2. Prepare a PDF of at most 100 pages and 25 MB, and obtain the US or Canadian destination fax number from the recipient's official site or form.
3. Ask the agent to call quote_fax with to and either document_url or document_base64. Review the destination, page count, and price; quoting sends nothing.
4. Ask for send_fax with the returned quote_id to obtain authorization instructions. Review them before paying; the tool itself does not charge. Paying the returned link transmits the fax. MCP payment requires an MPP-capable payer such as mppx or an agent wallet.
5. Use get_fax_status to check delivery and get_fax_receipt once the fax is final.

Pricing

$2.00 per fax by card, for up to 100 pages. Developers using a prepaid balance use REST or CLI with an account and API key. Developer API and prepaid balance rates are on Pricing.

FAQ

Do I need an Oh Fax account?

The MCP payment path needs no Oh Fax account or API key, but it does require an MPP-capable payer. Installing a connector alone does not provide a payer.

Can I send outside the US or Canada?

No. Oh Fax supports outbound US and Canadian destinations, with a 100-page PDF cap.