# libtmux.Server.confirm_before

- **Module:** libtmux.Server
- **Package:** libtmux
- **Language:** Python
- **Kind:** method
- **Source:** https://github.com/tmux-python/libtmux/blob/036c521c4b83ce6e434eb50afe2a0d08a6a05e46/src/libtmux/server.py#L1105
- **Page:** https://libtmux.org/reference/py/libtmux-server-confirm_before/

```
libtmux.Server.confirm_before(self, command: str, prompt: str | None = None, confirm_key: str | None = None, default_yes: bool | None = None, target_client: str | None = None) -> None
```

Run a command after confirmation via ``$ tmux confirm-before``.

Always uses ``-b`` (background) to avoid blocking the command queue.
Use ``send-keys -K -c <client>`` to provide the confirmation key.

Requires tmux 3.3+ for ``-b`` flag support.

## Parameters

- `self`
- `command` (str) — Tmux command to run after confirmation.
- `prompt` (str | None) — Custom prompt text (``-p`` flag).
- `confirm_key` (str | None) — Key to accept as confirmation (``-c`` flag). Default is ``y``.
Requires tmux 3.4+.
- `default_yes` (bool | None) — Make Enter default to yes (``-y`` flag). Requires tmux 3.4+.
- `target_client` (str | None) — Target client (``-t`` flag).

## Example

Interactive confirmation requires tmux 3.4+; the wrapper itself works on 3.3+ but the ``send-keys -K -c <client>`` round-trip used here is unreliable on 3.3a:

```python
>>> from libtmux.common import has_gte_version
>>> if has_gte_version("3.4"):
...     with control_mode() as ctl:
...         server.confirm_before(
...             'set -g @cf_test yes',
...             target_client=ctl.client_name,
...         )
...         _ = server.cmd('send-keys', '-K', '-c', ctl.client_name, 'y')
...         result = server.cmd('show-options', '-gv', '@cf_test').stdout[0]
... else:
...     result = 'yes'
>>> result
'yes'
```