Document string interpolation + add "debug:" alias

Author: Jeehut

README.md

@@ -67,6 +67,9 @@ do {
     // Better than localizedDescription, works with any error type
     print(ErrorKit.userFriendlyMessage(for: error))
     // "You are not connected to the Internet. Please check your connection."
+    
+    // String interpolation automatically uses userFriendlyMessage(for:)
+    print("Request failed: \(error)")
 }
 ```
 

Sources/ErrorKit/ErrorKit.docc/Guides/Enhanced-Error-Descriptions.md

@@ -81,6 +81,22 @@ If the error already conforms to `Throwable`, its `userFriendlyMessage` is used.
 
 All enhanced error messages are fully localized using the `String(localized:)` pattern, ensuring users receive messages in their preferred language where available.
 
+### String Interpolation Convenience
+
+ErrorKit enhances Swift's string interpolation to automatically use `userFriendlyMessage(for:)`:
+
+```swift
+// Instead of:
+showAlert(message: "Save failed: \(ErrorKit.userFriendlyMessage(for: error))")
+
+// You can simply use:
+showAlert(message: "Save failed: \(error)")
+Text("Could not load data: \(error)")
+Logger().info("Sync completed with error: \(error)")
+```
+
+This works with any error type — both your custom `Throwable` errors and system errors.
+
 ### How It Works
 
 The `userFriendlyMessage(for:)` function follows this process to determine the best error message:

Sources/ErrorKit/ErrorKit.docc/Guides/Error-Chain-Debugging.md

@@ -63,6 +63,21 @@ For errors conforming to the `Catching` protocol, you get the complete error wra
 
 Even for errors that don't conform to `Catching`, you still get valuable information since most Swift errors are enums. The error chain description will show you the exact enum case (e.g., `FileError.notFound`), making it easy to search your codebase for the error's origin. This is much better than the default cryptic message you get for enum cases when using `localizedDescription`.
 
+### String Interpolation for Debug Logging
+
+ErrorKit enhances string interpolation for error chain debugging. Use either `chain:` or `debug:` (they're aliases) to get the complete hierarchical description:
+
+```swift
+// Instead of:
+Logger().error("Update failed: \(ErrorKit.errorChainDescription(for: error))")
+
+// You can simply use either:
+Logger().error("Update failed:\n\(chain: error)")
+Logger().error("Update failed:\n\(debug: error)")
+```
+
+Use `\(error)` for user-facing messages, `\(chain: error)` or `\(debug: error)` for debugging.
+
 ### Error Analytics with Grouping IDs
 
 To help prioritize which errors to fix, ErrorKit provides `groupingID(for:)` that generates stable identifiers for errors sharing the exact same type structure and enum cases:

Sources/ErrorKit/Helpers/String+ErrorKit.swift

@@ -51,4 +51,25 @@ extension String.StringInterpolation {
    mutating public func appendInterpolation(chain error: some Error) {
       self.appendInterpolation(ErrorKit.errorChainDescription(for: error))
    }
+
+   /// Interpolates an error using its complete chain description for debugging.
+   ///
+   /// Uses ``ErrorKit.errorChainDescription(for:)`` to show the full error hierarchy,
+   /// type information, and nested structure. Ideal for logging and debugging.
+   ///
+   /// ```swift
+   /// Logger().error("Operation failed with:\n\(chain: error)")
+   /// // Operation failed with:
+   /// // DatabaseError
+   /// // └─ FileError
+   /// //    └─ PermissionError.denied(permission: "~/Downloads/Profile.png")
+   /// //       └─ userFriendlyMessage: "Access to ~/Downloads/Profile.png was declined..."
+   /// ```
+   ///
+   /// - Parameter error: The error to interpolate using its complete chain description
+   ///
+   /// - NOTE: Alias for ``appendInterpolation(chain:)``.
+   mutating public func appendInterpolation(debug error: some Error) {
+      self.appendInterpolation(chain: error)
+   }
 }