diff --git a/cli/src/commands/validate.zig b/cli/src/commands/validate.zig
index bbed22d..e229a06 100644
--- a/cli/src/commands/validate.zig
+++ b/cli/src/commands/validate.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const testing = std.testing;
 const Config = @import("../config.zig").Config;
 const ws = @import("../net/ws/client.zig");
+const protocol = @import("../net/protocol.zig");
 const colors = @import("../utils/colors.zig");
 const crypto = @import("../utils/crypto.zig");
 const io = @import("../utils/io.zig");
@@ -78,7 +79,7 @@ pub fn run(allocator: std.mem.Allocator, args: []const []const u8) !void {
     const msg = try client.receiveMessage(allocator);
     defer allocator.free(msg);
 
-    const packet = @import("../net/protocol.zig").ResponsePacket.deserialize(msg, allocator) catch {
+    const packet = protocol.ResponsePacket.deserialize(msg, allocator) catch {
         if (opts.json) {
             var out = io.stdoutWriter();
             try out.print("{s}\n", .{msg});
@@ -87,13 +88,7 @@ pub fn run(allocator: std.mem.Allocator, args: []const []const u8) !void {
         }
         return error.InvalidPacket;
     };
-    defer {
-        if (packet.success_message) |m| allocator.free(m);
-        if (packet.error_message) |m| allocator.free(m);
-        if (packet.error_details) |m| allocator.free(m);
-        if (packet.data_type) |m| allocator.free(m);
-        if (packet.data_payload) |m| allocator.free(m);
-    }
+    defer packet.deinit(allocator);
 
     if (packet.packet_type == .error_packet) {
         try client.handleResponsePacket(packet, "validate");
@@ -115,7 +110,7 @@ pub fn run(allocator: std.mem.Allocator, args: []const []const u8) !void {
 
         const root = parsed.value.object;
         const ok = try printHumanReport(root, opts.verbose);
-        if (!ok) std.process.exit(1);
+        if (!ok) return error.ValidationFailed;
     }
 }
 
diff --git a/cli/src/main.zig b/cli/src/main.zig
index 4db218d..088f79b 100644
--- a/cli/src/main.zig
+++ b/cli/src/main.zig
@@ -22,77 +22,57 @@ pub fn main() !void {
 
     const command = args[1];
 
-    // Track if we found a valid command
-    var command_found = false;
-
     // Fast dispatch using switch on first character
     switch (command[0]) {
         'j' => if (std.mem.eql(u8, command, "jupyter")) {
-            command_found = true;
             try @import("commands/jupyter.zig").run(allocator, args[2..]);
         },
         'i' => if (std.mem.eql(u8, command, "init")) {
-            command_found = true;
             colors.printInfo("Setup configuration interactively\n", .{});
         } else if (std.mem.eql(u8, command, "info")) {
-            command_found = true;
             try @import("commands/info.zig").run(allocator, args[2..]);
         },
         'a' => if (std.mem.eql(u8, command, "annotate")) {
-            command_found = true;
             try @import("commands/annotate.zig").run(allocator, args[2..]);
         },
         'n' => if (std.mem.eql(u8, command, "narrative")) {
-            command_found = true;
             try @import("commands/narrative.zig").run(allocator, args[2..]);
         },
         's' => if (std.mem.eql(u8, command, "sync")) {
-            command_found = true;
             if (args.len < 3) {
                 colors.printError("Usage: ml sync <path>\n", .{});
-                std.process.exit(1);
+                return error.InvalidArgs;
             }
             colors.printInfo("Sync project to server: {s}\n", .{args[2]});
         } else if (std.mem.eql(u8, command, "status")) {
-            command_found = true;
             try @import("commands/status.zig").run(allocator, args[2..]);
         },
         'r' => if (std.mem.eql(u8, command, "requeue")) {
-            command_found = true;
             try @import("commands/requeue.zig").run(allocator, args[2..]);
         },
         'q' => if (std.mem.eql(u8, command, "queue")) {
-            command_found = true;
             try @import("commands/queue.zig").run(allocator, args[2..]);
         },
         'd' => if (std.mem.eql(u8, command, "dataset")) {
-            command_found = true;
             try @import("commands/dataset.zig").run(allocator, args[2..]);
         },
         'e' => if (std.mem.eql(u8, command, "experiment")) {
-            command_found = true;
             try @import("commands/experiment.zig").execute(allocator, args[2..]);
         },
         'c' => if (std.mem.eql(u8, command, "cancel")) {
-            command_found = true;
             try @import("commands/cancel.zig").run(allocator, args[2..]);
         },
         'v' => if (std.mem.eql(u8, command, "validate")) {
-            command_found = true;
             try @import("commands/validate.zig").run(allocator, args[2..]);
         },
         'l' => if (std.mem.eql(u8, command, "logs")) {
-            command_found = true;
             try @import("commands/logs.zig").run(allocator, args[2..]);
         },
-        else => {},
-    }
-
-    // If no command was found, show error and exit
-    if (!command_found) {
-        colors.printError("Unknown command: {s}\n", .{args[1]});
-        printUsage();
-        std.process.exit(1);
+        else => {
+            colors.printError("Unknown command: {s}\n", .{args[1]});
+            printUsage();
+            return error.InvalidCommand;
+        },
     }
 }