# Transports (/cli/concepts/transports)



The CLI talks to Mogplex core over one of three transports. The router (`transport/router.ts`) is the **only** place that picks one.

## The three transports [#the-three-transports]

| Transport   | When it's used                                         | What it does                                                                                                         |
| ----------- | ------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------- |
| **process** | Default for an interactive terminal                    | Spawns a local exec runtime as a child process. The CLI watches its structured event stream and sends commands back. |
| **daemon**  | Attach mode (`--attach`) or `MOGPLEX_TRANSPORT=daemon` | Connects to a running mogplex daemon over a Unix socket. Lets you observe and steer a run that is already in flight. |
| **stdio**   | `MOGPLEX_TRANSPORT=stdio` or non-TTY stdin             | Reads JSONL events from stdin and writes commands to stdout. Used for piping events from another process.            |

## Selection rules [#selection-rules]

The router resolves the transport in this exact order:

1. `MOGPLEX_TRANSPORT=process` or `MOGPLEX_TRANSPORT=live` → **process**
2. `MOGPLEX_TRANSPORT=daemon` **or** `--attach <runId>` is set → **daemon**
3. `MOGPLEX_TRANSPORT=stdio` **or** stdin is a pipe (non-TTY) → **stdio**
4. Default (TTY stdin, no attach) → **process**

If selection somehow falls through, the router falls back to **daemon** and emits a `transport_fallback` diagnostic.

## Examples [#examples]

```bash
# Default — spawn a local exec process
mogplex

# Attach to an in-flight run via the daemon socket
mogplex --attach run_abc123

# Force stdio (typically used by tooling, not humans)
echo '{"type":"snapshot",...}' | MOGPLEX_TRANSPORT=stdio mogplex

# Force the process transport even when stdin is a pipe
MOGPLEX_TRANSPORT=process mogplex
```

## Permissions and the process transport [#permissions-and-the-process-transport]

The process transport reads runtime permissions from the active mode **at spawn time**. That means `/permissions auto` (or `/permissions approval`) takes effect on the **next** `/run` without restarting the CLI. Same store, same transport — only the spawn flags change.

See [Permissions](/cli/concepts/permissions).

## Daemon socket location [#daemon-socket-location]

When using the daemon transport, the socket path is read from `MOGPLEX_DAEMON_SOCKET`. If unset, the daemon's default location is used.

## Why this matters [#why-this-matters]

Most users never think about transports. They matter when:

* You're debugging "why isn't my run showing up?" — usually the transport selection picked the wrong thing because `MOGPLEX_TRANSPORT` is set in the shell.
* You want to attach to a long-running CI run from your laptop — that's daemon mode.
* You're piping structured events from another tool into the cockpit — that's stdio.

For the env-var reference, see [Configuration and Flags](/cli/guides/configuration-and-flags).