# Protocol Support

Multiple protocols are supported in the [Thanks, Computer](https://www.thanks.computer) chassis. They all become `JSON`.

## Protocols as JSON

We call the processes that speak the protocol a `head` in the `txco` chassis. These
ingress points speak the native protocol and then serialize it to a `JSON` event.
 
```json
{
  "_ts": "2026-06-18T16:58:59+02:00",
  "_txc": {
    "_seen": [
      "boot/0->boot/50",
      "boot/50->boot/100"
    ],
    "flag_breakpoint": true,
    "fuel_used": 105,
    "hostname_verified": true,
    "ingress": "host:build-1.local.thanks.computer",
    "rid": "CcAvW7aoT26xqmjgGVZbw",
    "src": "http",
    "stack": "build-1",
    "tenant": "default",
    "ttl": 497,
    "web": {
      "req": {
        "headers": {
          "Accept-Encoding": [
            "gzip"
          ],
          "User-Agent": [
            "Go-http-client/1.1"
          ]
        },
        "host": "build-1.local.thanks.computer",
        "method": "GET",
        "proto": "HTTP/1.1",
        "url": {
          "full": "/",
          "path": "/"
        }
      }
    }
  }
}
```

When these events arrive, the head that received it stamps `_txc.src` and its
own namespace (`@web.req.*`, `@lmtp.*`, `@cron.*`, `@tcp.*`, `@websocket.*`) onto one flow
envelope, and the same rules engine takes it from there. 

Each of these protocol heads also know how to convert back from the JSON event used
in an opstack's flows into the protocol.

## Protocols supported

| Channel | Direction |
|---|---|
| [HTTP](./web.md) | bidirectional, with streaming |
| [Email — receiving](./lmtp.md) | in |
| [Email — sending](./sendmail.md) | out |
| [Remote sources](./source.md) | in, pulled — the chassis watches an IMAP mailbox you already own and each new message is one run of `_source` |
| [Cron](./cron.md) | in |
| [Scheduled](./scheduled.md) | in, time shifted — `txco://schedule` enqueues, fires later into `_scheduled` |
| [TCP](./tcp.md) | bidirectional |
| [MCP](./mcp.md) (agent tools) | out, in as diy |
| [AI gateway](./llm-gateway.md) | in, then proxied out — an AI client's own requests, through a stack |
| [DNS](./dns.md) | authoritative answers for delegated zones; in, post-reply — answered queries flow into `_dns` |
| [IMAP](./imap.md) | out, read by a mail client — `txco://imap/append` materializes messages into a mailbox the `imap` head serves |
| [Calendar](./calendar.md) | out, read by a calendar app or a feed subscriber — `txco://calendar/put` materializes events into a calendar the `calendar` head serves over CalDAV and as ICS; client edits can come back as `_calendar` envelopes |
| [Contacts](./contacts.md) | out, read by a contacts app — `txco://contacts/put` materializes cards into an address book the `contacts` head serves over CardDAV; client edits can come back as `_contacts` envelopes |
| [WebSocket](./websocket.md) | bidirectional, session — a stack accepts the upgrade, each message is one run of `_websocket`, `txco://websocket/reply` answers on the socket |