diff --git a/README.md b/README.md
index 9f5ba65..0ce8c42 100644
--- a/README.md
+++ b/README.md
@@ -194,12 +194,13 @@ configuration section.
 > test environments (for example, `testenv:foo`). To override this, specify the setting in
 > the child environment with a different value.
 
-| Option                |  Type   | Default | Description                                                                                                                                                                                                                                                                                                                                                          |
-| :-------------------- | :-----: | :-----: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `locked_deps`         |  List   |  `[]`   | Names of packages to install to the test environment from the Poetry lockfile. Transient dependencies (packages required by these dependencies) are automatically included.                                                                                                                                                                                          |
-| `require_locked_deps` | Boolean |  False  | Whether the plugin should block attempts to install unlocked dependencies to the test environment. If enabled, then the [`tox_testenv_install_deps`](https://tox.readthedocs.io/en/latest/plugins.html#tox.hookspecs.tox_testenv_install_deps) plugin hook will be intercepted and an error will be raised if the test environment has the `deps` option configured. |
-| `install_dev_deps`    | Boolean |  False  | Whether all of the Poetry dev-dependencies should be installed to the test environment.                                                                                                                                                                                                                                                                              |
-| `require_poetry`      | Boolean |  False  | Whether Tox should be forced to fail if the plugin cannot import Poetry locally. If `False` then the plugin will be skipped for the test environment if Poetry cannot be imported. If `True` then the plugin will force the environment to error and the Tox run to fail.                                                                                            |
+| Option                 |  Type   | Default | Description                                                                                                                                                                                                                                                                                                                                                          |
+| :--------------------- | :-----: | :-----: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `locked_deps`          |  List   |  `[]`   | Names of packages to install to the test environment from the Poetry lockfile. Transient dependencies (packages required by these dependencies) are automatically included.                                                                                                                                                                                          |
+| `require_locked_deps`  | Boolean |  False  | Whether the plugin should block attempts to install unlocked dependencies to the test environment. If enabled, then the [`tox_testenv_install_deps`](https://tox.readthedocs.io/en/latest/plugins.html#tox.hookspecs.tox_testenv_install_deps) plugin hook will be intercepted and an error will be raised if the test environment has the `deps` option configured. |
+| `install_dev_deps`     | Boolean |  False  | Whether all of the Poetry dev-dependencies should be installed to the test environment.                                                                                                                                                                                                                                                                              |
+| `install_project_deps` | Boolean |  True   | Whether all of the Poetry primary dependencies for the project package should be installed to the test environment.                                                                                                                                                                                                                                                  |
+| `require_poetry`       | Boolean |  False  | Whether Tox should be forced to fail if the plugin cannot import Poetry locally. If `False` then the plugin will be skipped for the test environment if Poetry cannot be imported. If `True` then the plugin will force the environment to error and the Tox run to fail.                                                                                            |
 
 ### Runtime Options