> ## Documentation Index
> Fetch the complete documentation index at: https://docs.celesto.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# smolvm sandbox logs

> Use smolvm sandbox logs to inspect a sandbox's host-side boot and console log, with tail, follow, and JSON output for debugging startup and guest console messages.

`smolvm sandbox logs` prints the host-side boot and console log for a sandbox. Reach for it when a sandbox is slow to become ready, when `shell` or `ssh` won't connect, or when you want to see what the guest kernel and init printed on the serial console.

## Synopsis

```bash theme={null}
smolvm sandbox logs <sandbox> [OPTIONS]
```

## Arguments

<ParamField path="sandbox" type="string" required>
  Name or ID of the sandbox to read logs from.
</ParamField>

## Options

<ParamField path="--tail" type="number" default="200">
  Number of lines to show from the end of the log.
</ParamField>

<ParamField path="-f, --follow" type="flag">
  Keep printing new log lines as they arrive. Exit with `Ctrl+C`.
</ParamField>

<ParamField path="--json" type="flag">
  Emit a JSON envelope with the log content in `data` instead of streaming raw text.
</ParamField>

## Examples

### Show the last 200 lines

```bash theme={null}
smolvm sandbox logs my-sandbox
```

### Show more history

```bash theme={null}
smolvm sandbox logs my-sandbox --tail 1000
```

### Watch a boot live

```bash theme={null}
smolvm sandbox logs my-sandbox --follow
```

### Capture the log for a bug report

```bash theme={null}
smolvm sandbox logs my-sandbox --tail 500 --json > sandbox.log.json
```

## How it behaves

The command reads the boot/console log that SmolVM captures on the host, so it works even when the guest agent or SSH isn't reachable. `--follow` streams appended bytes through an incremental UTF-8 decoder, so multi-byte characters that span a read boundary aren't garbled, and the final line isn't split when the log lacks a trailing newline. Piping into a reader that closes early (for example `| head`) exits cleanly.

## Related commands

* [`smolvm sandbox exec`](/smolvm/cli/exec) - Run a command in a sandbox from a script
* [`smolvm sandbox shell`](/smolvm/cli/shell) - Open an interactive shell once the sandbox is up
* [`smolvm doctor`](/smolvm/cli/doctor) - Check whether the host can run SmolVM at all