Terminal Tax: E-file your federal taxes from your AI assistant

I built Terminal Tax so the tax conversation people already have with an AI assistant can end in an actual e-filed return. The assistant sends the figures from your forms to a hosted MCP server (https://mcp.terminal.tax/v1/host..., no account, key or install; anything that can make an HTTPS request can call it). Terminal Tax computes the return deterministically and validates it mechanically; it never guesses a tax fact or gives advice. You then open one filing page, review the complete return, type your SSN and PINs (those are refused from the assistant), sign, and authorize payment. $19.99 per federal return, charged only if the IRS accepts it. Federal 1040/1040-SR for tax year 2025 only for now; no state returns yet. Terminal Tax LLC is an Authorized IRS e-file Provider (Online Provider, Software Developer and Transmitter); acceptance to participate in IRS e-file does not imply endorsement by the IRS, and Terminal Tax is not affiliated with, sponsored by, or endorsed by the IRS or the U.S. Treasury. The developer guide is at https://terminal.tax/llms.txt. Happy to answer questions about the MCP design, the signing ceremony or the IRS e-file side.