Docs: Pre-filled variables require top-level definition

doc/ci/pipelines/index.md

@@ -147,10 +147,11 @@ The pipeline now executes the jobs as configured.
 > [Introduced in](https://gitlab.com/gitlab-org/gitlab/-/issues/30101) GitLab 13.7.
 
 You can use the [`value` and `description`](../yaml/README.md#prefill-variables-in-manual-pipelines)
-keywords to define [variables](../variables/README.md) that are prefilled when running
-a pipeline manually.
+keywords to define
+[pipeline-level (global) variables](../variables/README.md#create-a-custom-cicd-variable-in-the-gitlab-ciyml-file)
+that are prefilled when running a pipeline manually.
 
-In pipelines triggered manually, the **Run pipelines** page displays all variables
+In pipelines triggered manually, the **Run pipelines** page displays all top-level variables
 with a `description` and `value` defined in the `.gitlab-ci.yml` file. The values
 can then be modified if needed, which overrides the value for that single pipeline run.
 
@@ -164,6 +165,8 @@ variables:
     description: "The deployment target. Change this variable to 'canary' or 'production' if needed."
 ```
 
+You cannot set job-level variables to be pre-filled when you run a pipeline manually.
+
 ### Run a pipeline by using a URL query string
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/24146) in GitLab 12.5.

doc/ci/yaml/README.md

@@ -4781,7 +4781,7 @@ You can use [YAML anchors for variables](#yaml-anchors-for-variables).
 
 > [Introduced in](https://gitlab.com/gitlab-org/gitlab/-/issues/30101) GitLab 13.7.
 
-Use the `value` and `description` keywords to define [variables that are prefilled](../pipelines/index.md#prefill-variables-in-manual-pipelines)
+Use the `value` and `description` keywords to define [pipeline-level (global) variables that are prefilled](../pipelines/index.md#prefill-variables-in-manual-pipelines)
 when [running a pipeline manually](../pipelines/index.md#run-a-pipeline-manually):
 
 ```yaml
@@ -4791,6 +4791,8 @@ variables:
     description: "The deployment target. Change this variable to 'canary' or 'production' if needed."
 ```
 
+You cannot set job-level variables to be pre-filled when you run a pipeline manually.
+
 ### Configure runner behavior with variables
 
 You can use [CI/CD variables](../variables/README.md) to configure how the runner processes Git requests: