diff --git a/HISTORY.rst b/HISTORY.rst
index cd03107d..5d000e27 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -25,6 +25,7 @@ test-driven methodologies, and modern toolchains for unrivaled success.
 * Drastically enhanced the speed of project building when operating in verbose mode (`issue #4783 <https://github.com/platformio/platformio-core/issues/4783>`_)
 * Upgraded the build engine to the latest version of SCons (4.6.0) to improve build performance, reliability, and compatibility with other tools and systems (`release notes <https://github.com/SCons/scons/releases/tag/4.6.0>`__)
 * Enhanced the handling of built-in variables in |PIOCONF| during |INTERPOLATION| (`issue #4695 <https://github.com/platformio/platformio-core/issues/4695>`_)
+* Implemented a fail-safe mechanism to terminate a debugging session if an unknown CLI option is passed (`issue #4699 <https://github.com/platformio/platformio-core/issues/4699>`_)
 * Rectified an issue where ``${platformio.name}`` erroneously represented ``None`` as the default `project name <https://docs.platformio.org/en/latest/projectconf/sections/platformio/options/generic/name.html>`__ (`issue #4717 <https://github.com/platformio/platformio-core/issues/4717>`_)
 * Resolved an issue where the ``COMPILATIONDB_INCLUDE_TOOLCHAIN`` setting was not correctly applying to private libraries (`issue #4762 <https://github.com/platformio/platformio-core/issues/4762>`_)
 * Resolved an issue where ``get_systype()`` inaccurately returned the architecture when executed within a Docker container on a 64-bit kernel with a 32-bit userspace (`issue #4777 <https://github.com/platformio/platformio-core/issues/4777>`_)
diff --git a/platformio/debug/cli.py b/platformio/debug/cli.py
index 5c9375ae..4dc01686 100644
--- a/platformio/debug/cli.py
+++ b/platformio/debug/cli.py
@@ -54,7 +54,7 @@ from platformio.project.options import ProjectOptions
 @click.option("--environment", "-e", metavar="<environment>")
 @click.option("--load-mode", type=ProjectOptions["env.debug_load_mode"].type)
 @click.option("--verbose", "-v", is_flag=True)
-@click.option("--interface", type=click.Choice(["gdb"]))
+@click.option("--interface", type=click.Choice(["gdb"]), default="gdb")
 @click.argument("__unprocessed", nargs=-1, type=click.UNPROCESSED)
 @click.pass_context
 def cli(