Greet the user by their own first name, not a hardcoded one

NotchBuddy/NotchBuddy.xcodeproj/project.pbxproj

@@ -39,12 +39,14 @@
 		61CB7049490F61CFA1B36B64 /* AppLog.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9F6D7015D6A77AA59323C0E7 /* AppLog.swift */; };
 		61F73B27A7E3AFF584B2CC22 /* AppState.swift in Sources */ = {isa = PBXBuildFile; fileRef = C2E4F18AA940EFF7E047B9F7 /* AppState.swift */; };
 		62C4EE3F74DAA59764729E62 /* UploadCanvasView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B241B043223AFBBFB7418A5E /* UploadCanvasView.swift */; };
+		63F9F3AAC881D3EDDDD8AED9 /* UserIdentity.swift in Sources */ = {isa = PBXBuildFile; fileRef = F4A13AEE6E06F46CEC9D908C /* UserIdentity.swift */; };
 		651FA3F09608DE5D02D61CCE /* BotCanvasView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A29F4C0B02BE91654D02AA0C /* BotCanvasView.swift */; };
 		68A950E3C23FD612639D9776 /* IslandViewContent.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA02B08886939FF6FE0475DD /* IslandViewContent.swift */; };
 		6FC65C190ED614C664C9BC17 /* SafeWebURL.swift in Sources */ = {isa = PBXBuildFile; fileRef = B2FDED98F7F6C755A72C97A3 /* SafeWebURL.swift */; };
 		78B3C6814431B2DD9D1F4949 /* SoundEngine.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1BE21C2B315D37AA70ED45E9 /* SoundEngine.swift */; };
 		78FCEDC8F78B683AB10E6529 /* NotionPoller.swift in Sources */ = {isa = PBXBuildFile; fileRef = BE03E03D1804B0B92C5C2DAD /* NotionPoller.swift */; };
 		878924960FC0F2B3524D48AC /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 192844E7299DEED5C2372067 /* AppDelegate.swift */; };
+		8A6B3688D6B3BF728D106D8B /* UserIdentity.swift in Sources */ = {isa = PBXBuildFile; fileRef = F4A13AEE6E06F46CEC9D908C /* UserIdentity.swift */; };
 		8C32A0C3EAF536D3836F61D5 /* GreetingCanvasView.swift in Sources */ = {isa = PBXBuildFile; fileRef = C581F7B1A9F14B281B60063E /* GreetingCanvasView.swift */; };
 		8D1C01F283FA7806119A1C85 /* SettingsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7C1A7D5CBE2AC084A10C5FF3 /* SettingsView.swift */; };
 		967B525F7D3837F31D740D18 /* ResendPoller.swift in Sources */ = {isa = PBXBuildFile; fileRef = 61B5FDDE03F5F711146937E2 /* ResendPoller.swift */; };
@@ -110,6 +112,7 @@
 		D8212018F09EA1E96FBD63CD /* IslandStateMachine.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IslandStateMachine.swift; sourceTree = "<group>"; };
 		E91B733ADC638E14E9BB6EFA /* WindowContextCapture.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowContextCapture.swift; sourceTree = "<group>"; };
 		F1BD8F3CAA60CF37640759E1 /* NotchBuddyApp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotchBuddyApp.swift; sourceTree = "<group>"; };
+		F4A13AEE6E06F46CEC9D908C /* UserIdentity.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UserIdentity.swift; sourceTree = "<group>"; };
 		FA02B08886939FF6FE0475DD /* IslandViewContent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IslandViewContent.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -146,6 +149,7 @@
 				2EF78999D68D56ADE4CEFBE2 /* StripePoller.swift */,
 				B241B043223AFBBFB7418A5E /* UploadCanvasView.swift */,
 				6FD65943C32E150F1CD65C31 /* UploadSequenceEngine.swift */,
+				F4A13AEE6E06F46CEC9D908C /* UserIdentity.swift */,
 				71718D1B87A39A4879DD2A9D /* VercelPoller.swift */,
 				E91B733ADC638E14E9BB6EFA /* WindowContextCapture.swift */,
 			);
@@ -319,6 +323,7 @@
 				1558BB00C530B721172F6E65 /* StripePoller.swift in Sources */,
 				62C4EE3F74DAA59764729E62 /* UploadCanvasView.swift in Sources */,
 				FAD78D74C6906D4EC8AA4101 /* UploadSequenceEngine.swift in Sources */,
+				8A6B3688D6B3BF728D106D8B /* UserIdentity.swift in Sources */,
 				118FC4AE0AC74D84B4A134D8 /* VercelPoller.swift in Sources */,
 				2875610F701376BD65573386 /* WindowContextCapture.swift in Sources */,
 			);
@@ -357,6 +362,7 @@
 				E4B9986674F4D425826F15A8 /* StripePoller.swift in Sources */,
 				4117E7C8AA231AAE36E7509D /* UploadCanvasView.swift in Sources */,
 				ECECA2F225E82B7C951658D7 /* UploadSequenceEngine.swift in Sources */,
+				63F9F3AAC881D3EDDDD8AED9 /* UserIdentity.swift in Sources */,
 				0E83C1DD4D20E7FB7A904450 /* VercelPoller.swift in Sources */,
 				2CC2E3B688B15BBEB3AE3BCE /* WindowContextCapture.swift in Sources */,
 			);

NotchBuddy/Sources/App/ClaudeService.swift

@@ -190,12 +190,25 @@ final class ClaudeService {
         conversationMessages = []
     }
 
-    private let systemPrompt = """
-    You are Mochi, Louis's personal AI assistant embedded in the notch of his Mac. \
-    You have web search access and can help with absolutely anything — research, coding, finding places, recommendations, tasks, questions. \
-    Respond in the user's language. Be thorough and complete — use as much detail as the task requires. \
-    No markdown formatting (no **, no ##, no bullet dashes). Use plain text with line breaks.
-    """
+    /// Resolved once: NSFullUserName() is a system call, and the name cannot change under us
+    /// while the app runs.
+    private let systemPrompt = ClaudeService.makeSystemPrompt()
+
+    /// Greets the user by their macOS first name when there is one worth using, and stays
+    /// neutral otherwise — same wording as the Windows build.
+    private nonisolated static func makeSystemPrompt() -> String {
+        let opening = if let firstName = resolveUserFirstName() {
+            "You are Mochi, \(firstName)'s personal AI assistant embedded in the notch of their Mac."
+        } else {
+            "You are Mochi, a personal AI assistant embedded in the notch of the user's Mac."
+        }
+        return """
+        \(opening) \
+        You have web search access and can help with absolutely anything — research, coding, finding places, recommendations, tasks, questions. \
+        Respond in the user's language. Be thorough and complete — use as much detail as the task requires. \
+        No markdown formatting (no **, no ##, no bullet dashes). Use plain text with line breaks.
+        """
+    }
 
     private let webSearchTools: [[String: Any]] = [
         ["type": "web_search_20250305", "name": "web_search", "max_uses": 5]

NotchBuddy/Sources/App/UserIdentity.swift

@@ -0,0 +1,33 @@
+import Foundation
+
+/// First name of the macOS account holder, or nil when the account name is not something
+/// you would greet someone by. "Théodore Riant" gives "Théodore"; a login handle like
+/// "theodoreriant" or "t.riant2" gives nil, because "Hey theodoreriant!" reads worse than
+/// a greeting with no name at all.
+func resolveUserFirstName() -> String? {
+    let fullName = NSFullUserName().trimmingCharacters(in: .whitespacesAndNewlines)
+    guard !fullName.isEmpty, fullName.count <= maxUserFullNameLength else { return nil }
+    guard !looksLikeLoginHandle(fullName) else { return nil }
+
+    guard let first = fullName.split(separator: " ").first.map(String.init),
+          !first.isEmpty,
+          first.allSatisfy(isNamePart) else { return nil }
+    return first
+}
+
+/// NSFullUserName() falls back to the short account name when the full name is unset, so a
+/// single lowercase word, or one carrying digits or separators, is treated as a handle.
+private func looksLikeLoginHandle(_ name: String) -> Bool {
+    guard !name.contains(" ") else { return false }
+    return name == name.lowercased() || name.contains(where: isHandleMarker)
+}
+
+private func isHandleMarker(_ character: Character) -> Bool {
+    character.isNumber || "._-@".contains(character)
+}
+
+private func isNamePart(_ character: Character) -> Bool {
+    character.isLetter || character == "'" || character == "-"
+}
+
+private let maxUserFullNameLength = 32