diff --git a/.gitlab/README.md.template b/.gitlab/README.md.template
index f1737298909cc067c8d36837c87e358240ac7f1a..d48a45ed6c3d34848156d0cdf54f763bb1372191 100644
--- a/.gitlab/README.md.template
+++ b/.gitlab/README.md.template
@@ -300,6 +300,9 @@ and will try to execute a `tofu` command.
 In this case you can set the `GITLAB_TOFU_SOURCE` environment variable
 to `true` before sourcing `gitlab-tofu`.
 
+When the `gitlab-tofu` script is sourced it'll set the `GITLAB_TOFU_SOURCED`
+variable to `true`. This variable is not exported by the script itself.
+
 ### Best Practices
 
 This section is a collection of *some* best practices.
diff --git a/README.md b/README.md
index c2e88f42bd106ab79e482b207465a79e9e2bfb3a..11e74bb8dd06b5ad5dffc2f99f7ac5941eaca90b 100644
--- a/README.md
+++ b/README.md
@@ -315,6 +315,9 @@ and will try to execute a `tofu` command.
 In this case you can set the `GITLAB_TOFU_SOURCE` environment variable
 to `true` before sourcing `gitlab-tofu`.
 
+When the `gitlab-tofu` script is sourced it'll set the `GITLAB_TOFU_SOURCED`
+variable to `true`. This variable is not exported by the script itself.
+
 ### Best Practices
 
 This section is a collection of *some* best practices.
diff --git a/src/gitlab-tofu.sh b/src/gitlab-tofu.sh
index 075c6d212f2ead8230f186f05dde34e79b1f691e..3e9c167d34abe5f53acb24bc9d215f848412b3bb 100644
--- a/src/gitlab-tofu.sh
+++ b/src/gitlab-tofu.sh
@@ -18,6 +18,7 @@ fi
 # Evaluate if this script is being sourced or executed directly.
 # See https://stackoverflow.com/a/28776166
 sourced=0
+# shellcheck disable=SC2153 # it's actually a different variable, thanks shelllcheck.
 if [ "$GITLAB_TOFU_SOURCE" = 'true' ]; then
   sourced=1
 elif [ -n "$ZSH_VERSION" ]; then
@@ -276,5 +277,5 @@ if [ $sourced -eq 0 ]; then
 else
   # This variable can be used if the script is sourced
   # shellcheck disable=SC2034
-  TF_GITLAB_SOURCED=true
+  GITLAB_TOFU_SOURCED=true
 fi
diff --git a/tests/unit/gitlab-tofu.bats b/tests/unit/gitlab-tofu.bats
index faf2d312ed717a377ccb243c4585886a5a9cb84f..5b00ef1879529ec32d0fea08091ea368675e0c83 100644
--- a/tests/unit/gitlab-tofu.bats
+++ b/tests/unit/gitlab-tofu.bats
@@ -151,9 +151,9 @@ EOF
 
   cat <<'EOF' > test.sh
 set -x
-test -z "$TF_GITLAB_SOURCED"
+test -z "$GITLAB_TOFU_SOURCED"
 . $(which gitlab-tofu)
-test "$TF_GITLAB_SOURCED"
+test "$GITLAB_TOFU_SOURCED"
 EOF
 
   $SHELL test.sh
@@ -165,9 +165,9 @@ EOF
 
   cat <<'EOF' > test.sh
 set -x
-test -z "$TF_GITLAB_SOURCED"
+test -z "$GITLAB_TOFU_SOURCED"
 . $(which gitlab-tofu)
-test "$TF_GITLAB_SOURCED"
+test "$GITLAB_TOFU_SOURCED"
 EOF
 
   mkdir -p /usr/local/sbin