Add Cursor CLI detection to AiCliDetector

Introduces detection for the Cursor CLI by checking for the CURSOR_AGENT environment variable. Updates related tests and documentation to include the new IsCursor property.

Author: SimonCropp

readme.md

@@ -178,10 +178,11 @@ There are also individual properties to check for each specific AI CLI
 <a id='snippet-AiCliDetectorProps'></a>
 ```cs
 var isCopilot = AiCliDetector.IsCopilot;
+var isCursor = AiCliDetector.IsCursor;
 var isAider = AiCliDetector.IsAider;
 var isClaudeCode = AiCliDetector.IsClaudeCode;
 ```
-<sup><a href='/src/DiffEngine.Tests/AiCliDetectorTest.cs#L9-L15' title='Snippet source file'>snippet source</a> | <a href='#snippet-AiCliDetectorProps' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/DiffEngine.Tests/AiCliDetectorTest.cs#L9-L16' title='Snippet source file'>snippet source</a> | <a href='#snippet-AiCliDetectorProps' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 

src/DiffEngine.Tests/AiCliDetectorTest.cs

@@ -9,6 +9,7 @@ public void Props()
         #region AiCliDetectorProps
 
         var isCopilot = AiCliDetector.IsCopilot;
+        var isCursor = AiCliDetector.IsCursor;
         var isAider = AiCliDetector.IsAider;
         var isClaudeCode = AiCliDetector.IsClaudeCode;
 

src/DiffEngine/AiCliDetector.cs

@@ -18,11 +18,18 @@ static AiCliDetector()
         // https://docs.anthropic.com/en/docs/build-with-claude/claude-cli
         IsClaudeCode = variables.Contains("CLAUDECODE") || variables.Contains("CLAUDE_CODE_ENTRYPOINT");
 
+        // Cursor
+        // https://cursor.com/docs/agent/terminal
+        IsCursor = variables.Contains("CURSOR_AGENT");
+
         Detected = IsCopilot ||
                    IsAider ||
-                   IsClaudeCode;
+                   IsClaudeCode ||
+                   IsCursor;
     }
 
+    public static bool IsCursor { get; set; }
+
     public static bool IsCopilot { get; }
 
     public static bool IsAider { get; }