docs: document interface.marketplace.categories

content/docs/configuration/librechat_yaml/object_structure/interface.mdx

@@ -1212,20 +1212,25 @@ interface:
 
 ## marketplace
 
-Enables/disables access to the Agent Marketplace.
+Enables/disables access to the Agent Marketplace and, optionally, defines custom categories used to organize agents within it.
 
 > **Deprecated for permission management.** Seeds the `MARKETPLACE` role permission at startup for the default `USER` role only. Prefer the [Admin Panel](/docs/features/admin_panel).
 
 **Key:**
 
 <OptionTable
-  options={[['marketplace', 'Object', 'Configuration for Agent Marketplace access control.']]}
+  options={[
+    ['marketplace', 'Object', 'Configuration for Agent Marketplace access control and custom categories.'],
+  ]}
 />
 
 **Sub-keys:**
 
 <OptionTable
-  options={[['use', 'Boolean', 'Enables or disables marketplace access. Default: false']]}
+  options={[
+    ['use', 'Boolean', 'Enables or disables marketplace access. Default: false'],
+    ['categories', 'Object', 'Optional. Configures default and custom marketplace categories. Only applied when use is true. See below.'],
+  ]}
 />
 
 **Default:**
@@ -1242,3 +1247,48 @@ interface:
   marketplace:
     use: true # Enable marketplace access
 ```
+
+### categories
+
+Customizes the categories displayed in the Agent Marketplace. The list is synced to the database on startup: new entries are created, existing entries are updated, and custom entries removed from the YAML are deleted from the database. Categories are only synced when `marketplace.use` is `true`.
+
+**Key:**
+<OptionTable
+  options={[
+    ['categories', 'Object', 'Configuration for marketplace categories. Synced to the database on startup.'],
+  ]}
+/>
+
+**Sub-keys:**
+
+<OptionTable
+  options={[
+    ['enableDefaultCategories', 'Boolean', "When true, LibreChat's built-in default categories are kept active and appear before custom categories. Default: true"],
+    ['list', 'Array of Objects', 'Ordered list of custom categories. The declared order is preserved in the marketplace UI (after default categories when enableDefaultCategories is true).'],
+  ]}
+/>
+
+**`list` item sub-keys:**
+
+<OptionTable
+  options={[
+    ['value', 'String', 'Display name for the category. Stored lowercase internally and treated case-insensitively when matching existing categories.'],
+    ['description', 'String', 'Short description shown alongside the category in the marketplace.'],
+  ]}
+/>
+
+**Example:**
+```yaml filename="interface / marketplace / categories"
+interface:
+  marketplace:
+    use: true
+    categories:
+      enableDefaultCategories: true  # Built-in categories appear first
+      list:                          # Order here determines marketplace order
+        - value: "Education"
+          description: "Educational agents."
+        - value: "Productivity"
+          description: "Productivity agents."
+```
+
+> **Note:** Removing a custom category from `list` deletes it from the database on the next startup. Default categories are never deleted, `enableDefaultCategories: false` only hides them.