Documenting a custom geoprocessing tool allows others to understand and use your tool efficiently. The documentation can be authored in part using the tool properties dialog box, as well as the tool metadata.
Tool properties
Set the properties listed below to document the tool in the Properties dialog box. To open the Properties dialog box, right-click the tool in the Catalog pane.
- On the General side tab, provide a tool description, summary, and illustration.
- On the Parameters side tab, set a description for each parameter that displays on the tool dialog box when you hover over the Information button
next to the parameter label.
Metadata
To author a tool's complete help documentation, modify its metadata, or item description, which contains the following components:
- Title—The custom tool’s name.
- Thumbnail—A thumbnail that is displayed when you hover over the tool in the Catalog pane.
- Tags—Keywords used to search for tools in the Catalog pane or Catalog view.
- Summary (Abstract)—A summary of the task the tool performs as well as brief use cases. The summary displays when you hover over the Help button
in the Geoprocessing pane.Note:
If the summary is set in the tool metadata and on the Properties dialog box, the summary from the tools properties will display on the tool dialog.
- Usage—General tips or instructions on how to correctly and efficiently use the tool.
- Syntax—Specific help for each parameter, including acceptable data types and values.
Code samples, credits, use constraints, and a bounding box can also be documented in the metadata.
To document the custom geoprocessing tool and toolbox, right-click the tool or toolbox and select Edit Metadata. Alternatively, right-click the tool or toolbox, select View Metadata, and click the Edit button 
on the Catalog tab. After you have documented your custom tool, anyone using the tool can get help for the tool in the same way they get help for the geoprocessing tools included in ArcGIS Pro.