build: add check step to verify compilation

MCP fixes

build.zig

@@ -85,6 +85,15 @@ pub fn build(b: *Build) !void {
         break :blk mod;
     };
 
+    // Check compilation
+    const check = b.step("check", "Check if lightpanda compiles");
+
+    const check_lib = b.addLibrary(.{
+        .name = "lightpanda_check",
+        .root_module = lightpanda_module,
+    });
+    check.dependOn(&check_lib.step);
+
     {
         // browser
         const exe = b.addExecutable(.{
@@ -103,6 +112,12 @@ pub fn build(b: *Build) !void {
         });
         b.installArtifact(exe);
 
+        const exe_check = b.addLibrary(.{
+            .name = "lightpanda_exe_check",
+            .root_module = exe.root_module,
+        });
+        check.dependOn(&exe_check.step);
+
         const run_cmd = b.addRunArtifact(exe);
         if (b.args) |args| {
             run_cmd.addArgs(args);
@@ -132,6 +147,12 @@ pub fn build(b: *Build) !void {
         });
         b.installArtifact(exe);
 
+        const exe_check = b.addLibrary(.{
+            .name = "snapshot_creator_check",
+            .root_module = exe.root_module,
+        });
+        check.dependOn(&exe_check.step);
+
         const run_cmd = b.addRunArtifact(exe);
         if (b.args) |args| {
             run_cmd.addArgs(args);
@@ -170,6 +191,12 @@ pub fn build(b: *Build) !void {
         });
         b.installArtifact(exe);
 
+        const exe_check = b.addLibrary(.{
+            .name = "legacy_test_check",
+            .root_module = exe.root_module,
+        });
+        check.dependOn(&exe_check.step);
+
         const run_cmd = b.addRunArtifact(exe);
         if (b.args) |args| {
             run_cmd.addArgs(args);

src/browser/URL.zig

@@ -357,25 +357,38 @@ pub fn isHTTPS(raw: [:0]const u8) bool {
 
 pub fn getHostname(raw: [:0]const u8) []const u8 {
     const host = getHost(raw);
-    const pos = std.mem.lastIndexOfScalar(u8, host, ':') orelse return host;
-    return host[0..pos];
+    const port_sep = findPortSeparator(host) orelse return host;
+    return host[0..port_sep];
 }
 
 pub fn getPort(raw: [:0]const u8) []const u8 {
     const host = getHost(raw);
-    const pos = std.mem.lastIndexOfScalar(u8, host, ':') orelse return "";
+    const port_sep = findPortSeparator(host) orelse return "";
+    return host[port_sep + 1 ..];
+}
 
-    if (pos + 1 >= host.len) {
-        return "";
+// Finds the colon separating host from port, handling IPv6 bracket notation.
+// For IPv6 like "[::1]:8080", returns position of ":" after "]".
+// For IPv6 like "[::1]" (no port), returns null.
+// For regular hosts, returns position of last ":" if followed by digits.
+fn findPortSeparator(host: []const u8) ?usize {
+    if (host.len > 0 and host[0] == '[') {
+        // IPv6: find closing bracket, port separator must be after it
+        const bracket_end = std.mem.indexOfScalar(u8, host, ']') orelse return null;
+        if (bracket_end + 1 < host.len and host[bracket_end + 1] == ':') {
+            return bracket_end + 1;
+        }
+        return null;
     }
 
+    // Regular host: find last colon and verify it's followed by digits
+    const pos = std.mem.lastIndexOfScalar(u8, host, ':') orelse return null;
+    if (pos + 1 >= host.len) return null;
+
     for (host[pos + 1 ..]) |c| {
-        if (c < '0' or c > '9') {
-            return "";
-        }
+        if (c < '0' or c > '9') return null;
     }
-
-    return host[pos + 1 ..];
+    return pos;
 }
 
 pub fn getSearch(raw: [:0]const u8) []const u8 {
@@ -403,23 +416,12 @@ pub fn getOrigin(allocator: Allocator, raw: [:0]const u8) !?[]const u8 {
         return null;
     }
 
-    var authority_start = scheme_end + 3;
-
-    // Find end of authority (start of path/query/fragment or end of string)
-    const authority_end_relative = std.mem.indexOfAny(u8, raw[authority_start..], "/?#");
-    const authority_end = if (authority_end_relative) |end|
-        authority_start + end
-    else
-        raw.len;
-
-    // We mustn't search the `@` after the first path separator.
-    const has_user_info = if (std.mem.indexOf(u8, raw[authority_start..authority_end], "@")) |pos| blk: {
-        authority_start += pos + 1;
-        break :blk true;
-    } else false;
+    const auth = parseAuthority(raw) orelse return null;
+    const has_user_info = auth.has_user_info;
+    const authority_end = auth.host_end;
 
     // Check for port in the host:port section
-    const host_part = raw[authority_start..authority_end];
+    const host_part = auth.getHost(raw);
     if (std.mem.lastIndexOfScalar(u8, host_part, ':')) |colon_pos_in_host| {
         const port = host_part[colon_pos_in_host + 1 ..];
 
@@ -460,45 +462,18 @@ pub fn getOrigin(allocator: Allocator, raw: [:0]const u8) !?[]const u8 {
 }
 
 fn getUserInfo(raw: [:0]const u8) ?[]const u8 {
-    const scheme_end = std.mem.indexOf(u8, raw, "://") orelse return null;
+    const auth = parseAuthority(raw) orelse return null;
+    if (!auth.has_user_info) return null;
+
+    // User info is from authority_start to host_start - 1 (excluding the @)
+    const scheme_end = std.mem.indexOf(u8, raw, "://").?;
     const authority_start = scheme_end + 3;
-
-    // We mustn't search the `@` after the first path separator.
-    const path_start = blk: {
-        if (std.mem.indexOfAny(u8, raw[authority_start..], "/?#")) |idx| {
-            break :blk authority_start + idx;
-        }
-        break :blk raw.len;
-    };
-
-    const pos = std.mem.indexOfScalar(u8, raw[authority_start..path_start], '@') orelse return null;
-
-    const full_pos = authority_start + pos;
-    if (full_pos < path_start) {
-        return raw[authority_start..full_pos];
-    }
-
-    return null;
+    return raw[authority_start .. auth.host_start - 1];
 }
 
 pub fn getHost(raw: [:0]const u8) []const u8 {
-    const scheme_end = std.mem.indexOf(u8, raw, "://") orelse return "";
-
-    var authority_start = scheme_end + 3;
-
-    // We mustn't search the `@` after the first path separator.
-    const path_start = blk: {
-        if (std.mem.indexOfAny(u8, raw[authority_start..], "/?#")) |idx| {
-            break :blk authority_start + idx;
-        }
-        break :blk raw.len;
-    };
-
-    if (std.mem.indexOf(u8, raw[authority_start..path_start], "@")) |pos| {
-        authority_start += pos + 1;
-    }
-
-    return raw[authority_start..path_start];
+    const auth = parseAuthority(raw) orelse return "";
+    return auth.getHost(raw);
 }
 
 // Returns true if these two URLs point to the same document.
@@ -777,6 +752,47 @@ pub fn unescape(arena: Allocator, input: []const u8) ![]const u8 {
     return result.items;
 }
 
+const AuthorityInfo = struct {
+    host_start: usize,
+    host_end: usize,
+    has_user_info: bool,
+
+    fn getHost(self: AuthorityInfo, raw: []const u8) []const u8 {
+        return raw[self.host_start..self.host_end];
+    }
+};
+
+// Parses the authority component of a URL, correctly handling userinfo.
+// Returns null if the URL doesn't have a valid scheme (no "://").
+// SECURITY: Only looks for @ within the authority portion (before /?#)
+// to prevent path-based @ injection attacks.
+fn parseAuthority(raw: []const u8) ?AuthorityInfo {
+    const scheme_end = std.mem.indexOf(u8, raw, "://") orelse return null;
+    const authority_start = scheme_end + 3;
+
+    // Find end of authority FIRST (start of path/query/fragment or end of string)
+    const authority_end = if (std.mem.indexOfAny(u8, raw[authority_start..], "/?#")) |end|
+        authority_start + end
+    else
+        raw.len;
+
+    // Only look for @ within the authority portion, not in path/query/fragment
+    const authority_portion = raw[authority_start..authority_end];
+    if (std.mem.indexOf(u8, authority_portion, "@")) |pos| {
+        return .{
+            .host_start = authority_start + pos + 1,
+            .host_end = authority_end,
+            .has_user_info = true,
+        };
+    }
+
+    return .{
+        .host_start = authority_start,
+        .host_end = authority_end,
+        .has_user_info = false,
+    };
+}
+
 const testing = @import("../testing.zig");
 test "URL: isCompleteHTTPUrl" {
     try testing.expectEqual(true, isCompleteHTTPUrl("http://example.com/about"));
@@ -1445,6 +1461,42 @@ test "URL: getHost" {
     try testing.expectEqualSlices(u8, "example.com", getHost("https://user:pass@example.com/page"));
     try testing.expectEqualSlices(u8, "example.com:8080", getHost("https://user:pass@example.com:8080/page"));
     try testing.expectEqualSlices(u8, "", getHost("not-a-url"));
+
+    // SECURITY: @ in path must NOT be treated as userinfo separator
+    try testing.expectEqualSlices(u8, "evil.example.com", getHost("http://evil.example.com/@victim.example.com/"));
+    try testing.expectEqualSlices(u8, "evil.example.com", getHost("https://evil.example.com/path/@victim.example.com"));
+
+    // IPv6 addresses
+    try testing.expectEqualSlices(u8, "[::1]:8080", getHost("http://[::1]:8080/path"));
+    try testing.expectEqualSlices(u8, "[::1]", getHost("http://[::1]/path"));
+    try testing.expectEqualSlices(u8, "[2001:db8::1]", getHost("https://[2001:db8::1]/"));
+}
+
+test "URL: getHostname" {
+    // Regular hosts
+    try testing.expectEqualSlices(u8, "example.com", getHostname("https://example.com:8080/path"));
+    try testing.expectEqualSlices(u8, "example.com", getHostname("https://example.com/path"));
+
+    // IPv6 with port
+    try testing.expectEqualSlices(u8, "[::1]", getHostname("http://[::1]:8080/path"));
+
+    // IPv6 without port - must return full bracket notation
+    try testing.expectEqualSlices(u8, "[::1]", getHostname("http://[::1]/path"));
+    try testing.expectEqualSlices(u8, "[2001:db8::1]", getHostname("https://[2001:db8::1]/"));
+}
+
+test "URL: getPort" {
+    // Regular hosts
+    try testing.expectEqualSlices(u8, "8080", getPort("https://example.com:8080/path"));
+    try testing.expectEqualSlices(u8, "", getPort("https://example.com/path"));
+
+    // IPv6 with port
+    try testing.expectEqualSlices(u8, "8080", getPort("http://[::1]:8080/path"));
+    try testing.expectEqualSlices(u8, "3000", getPort("http://[2001:db8::1]:3000/"));
+
+    // IPv6 without port - colons inside brackets must not be treated as port separator
+    try testing.expectEqualSlices(u8, "", getPort("http://[::1]/path"));
+    try testing.expectEqualSlices(u8, "", getPort("https://[2001:db8::1]/"));
 }
 
 test "URL: setPathname percent-encodes" {
@@ -1467,34 +1519,54 @@ test "URL: setPathname percent-encodes" {
 }
 
 test "URL: getOrigin" {
-    var arena = std.heap.ArenaAllocator.init(testing.allocator);
-    defer arena.deinit();
-    const allocator = arena.allocator();
-    try testing.expectEqualSlices(u8, "http://example.com:8080", try getOrigin(allocator, "http://example.com:8080/path") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://example.com:8080", try getOrigin(allocator, "https://example.com:8080/path") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://example.com", try getOrigin(allocator, "https://example.com/path") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://example.com", try getOrigin(allocator, "https://example.com:443/") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://example.com", try getOrigin(allocator, "https://user:pass@example.com/page") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://example.com:8080", try getOrigin(allocator, "https://user:pass@example.com:8080/page") orelse unreachable);
-    try testing.expectEqual(null, try getOrigin(allocator, "not-a-url"));
-}
+    defer testing.reset();
 
-test "URL: SOP bypass" {
-    // SOP Bypass
-    try testing.expectEqualSlices(u8, "attacker.com", getHost("http://attacker.com/@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHost("https://attacker.com/@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHost("http://attacker.com?@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHost("http://attacker.com#@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHostname("http://attacker.com/@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHostname("https://attacker.com/@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHostname("http://attacker.com?@bank.com/"));
-    try testing.expectEqualSlices(u8, "attacker.com", getHostname("http://attacker.com#@bank.com/"));
+    const Case = struct {
+        url: [:0]const u8,
+        expected: ?[]const u8,
+    };
 
-    var arena = std.heap.ArenaAllocator.init(testing.allocator);
-    defer arena.deinit();
-    const allocator = arena.allocator();
-    try testing.expectEqualSlices(u8, "http://attacker.com", try getOrigin(allocator, "http://attacker.com/@bank.com/") orelse unreachable);
-    try testing.expectEqualSlices(u8, "https://attacker.com", try getOrigin(allocator, "https://attacker.com/@bank.com/") orelse unreachable);
-    try testing.expectEqualSlices(u8, "http://attacker.com", try getOrigin(allocator, "http://attacker.com?bank.com/") orelse unreachable);
-    try testing.expectEqualSlices(u8, "http://attacker.com", try getOrigin(allocator, "http://attacker.com#bank.com/") orelse unreachable);
+    const cases = [_]Case{
+        // Basic HTTP/HTTPS origins
+        .{ .url = "http://example.com/path", .expected = "http://example.com" },
+        .{ .url = "https://example.com/path", .expected = "https://example.com" },
+        .{ .url = "https://example.com:8080/path", .expected = "https://example.com:8080" },
+
+        // Default ports should be stripped
+        .{ .url = "http://example.com:80/path", .expected = "http://example.com" },
+        .{ .url = "https://example.com:443/path", .expected = "https://example.com" },
+
+        // User info should be stripped from origin
+        .{ .url = "http://user:pass@example.com/path", .expected = "http://example.com" },
+        .{ .url = "https://user@example.com:8080/path", .expected = "https://example.com:8080" },
+
+        // Non-HTTP schemes return null
+        .{ .url = "ftp://example.com/path", .expected = null },
+        .{ .url = "file:///path/to/file", .expected = null },
+        .{ .url = "about:blank", .expected = null },
+
+        // Query and fragment should not affect origin
+        .{ .url = "https://example.com?query=1", .expected = "https://example.com" },
+        .{ .url = "https://example.com#fragment", .expected = "https://example.com" },
+        .{ .url = "https://example.com/path?q=1#frag", .expected = "https://example.com" },
+
+        // SECURITY: @ in path must NOT be treated as userinfo separator
+        // This would be a Same-Origin Policy bypass if mishandled
+        .{ .url = "http://evil.example.com/@victim.example.com/", .expected = "http://evil.example.com" },
+        .{ .url = "https://evil.example.com/path/@victim.example.com/steal", .expected = "https://evil.example.com" },
+        .{ .url = "http://evil.example.com/@victim.example.com:443/", .expected = "http://evil.example.com" },
+
+        // @ in query/fragment must also not affect origin
+        .{ .url = "https://example.com/path?user=foo@bar.com", .expected = "https://example.com" },
+        .{ .url = "https://example.com/path#user@host", .expected = "https://example.com" },
+    };
+
+    for (cases) |case| {
+        const result = try getOrigin(testing.arena_allocator, case.url);
+        if (case.expected) |expected| {
+            try testing.expectString(expected, result.?);
+        } else {
+            try testing.expectEqual(null, result);
+        }
+    }
 }

src/browser/interactive.zig

@@ -36,6 +36,7 @@ pub const InteractivityType = enum {
 };
 
 pub const InteractiveElement = struct {
+    backendNodeId: ?u32 = null,
     node: *Node,
     tag_name: []const u8,
     role: ?[]const u8,
@@ -55,6 +56,11 @@ pub const InteractiveElement = struct {
     pub fn jsonStringify(self: *const InteractiveElement, jw: anytype) !void {
         try jw.beginObject();
 
+        if (self.backendNodeId) |id| {
+            try jw.objectField("backendNodeId");
+            try jw.write(id);
+        }
+
         try jw.objectField("tagName");
         try jw.write(self.tag_name);
 
@@ -123,6 +129,15 @@ pub const InteractiveElement = struct {
     }
 };
 
+/// Populate backendNodeId on each interactive element by registering
+/// their nodes in the given registry. Works with both CDP and MCP registries.
+pub fn registerNodes(elements: []InteractiveElement, registry: anytype) !void {
+    for (elements) |*el| {
+        const registered = try registry.register(el.node);
+        el.backendNodeId = registered.id;
+    }
+}
+
 /// Collect all interactive elements under `root`.
 pub fn collectInteractiveElements(
     root: *Node,

src/browser/js/bridge.zig

@@ -853,6 +853,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/event/InputEvent.zig"),
     @import("../webapi/event/PromiseRejectionEvent.zig"),
     @import("../webapi/event/SubmitEvent.zig"),
+    @import("../webapi/event/FormDataEvent.zig"),
     @import("../webapi/MessageChannel.zig"),
     @import("../webapi/MessagePort.zig"),
     @import("../webapi/media/MediaError.zig"),

src/browser/links.zig

@@ -0,0 +1,54 @@
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Element = @import("webapi/Element.zig");
+const Node = @import("webapi/Node.zig");
+const Page = @import("Page.zig");
+const Selector = @import("webapi/selector/Selector.zig");
+
+const Allocator = std.mem.Allocator;
+
+/// Collect all links (href attributes from anchor tags) under `root`.
+/// Returns a slice of strings allocated with `arena`.
+pub fn collectLinks(arena: Allocator, root: *Node, page: *Page) ![]const []const u8 {
+    var links: std.ArrayList([]const u8) = .empty;
+
+    if (Selector.querySelectorAll(root, "a[href]", page)) |list| {
+        defer list.deinit(page._session);
+
+        for (list._nodes) |node| {
+            if (node.is(Element.Html.Anchor)) |anchor| {
+                const href = anchor.getHref(page) catch |err| {
+                    @import("../lightpanda.zig").log.err(.app, "resolve href failed", .{ .err = err });
+                    continue;
+                };
+
+                if (href.len > 0) {
+                    try links.append(arena, href);
+                }
+            }
+        }
+    } else |err| {
+        @import("../lightpanda.zig").log.err(.app, "query links failed", .{ .err = err });
+        return err;
+    }
+
+    return links.items;
+}

src/browser/tests/canvas/canvas_rendering_context_2d.html

@@ -125,6 +125,19 @@
 </script>
 
 
+<script id="CanvasRenderingContext2D#canvas">
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("2d");
+  testing.expectEqual(ctx.canvas, element);
+  // Setting dimensions via ctx.canvas should update the element.
+  ctx.canvas.width = 40;
+  ctx.canvas.height = 25;
+  testing.expectEqual(element.width, 40);
+  testing.expectEqual(element.height, 25);
+}
+</script>
+
 <script id="getter">
 {
   const element = document.createElement("canvas");

src/browser/tests/net/form_data.html

@@ -734,3 +734,101 @@
   testing.expectEqual([['field', 'data'], ['x', '0'], ['y', '0']], entries);
 }
 </script>
+
+<script id=formDataEventFires>
+{
+  // formdata event fires on the form when FormData is constructed with a form
+  const form = document.createElement('form');
+
+  const input = document.createElement('input');
+  input.name = 'field';
+  input.value = 'hello';
+  form.appendChild(input);
+
+  let eventFired = false;
+  let receivedFormData = null;
+
+  form.addEventListener('formdata', (e) => {
+    eventFired = true;
+    receivedFormData = e.formData;
+  });
+
+  const fd = new FormData(form);
+  testing.expectEqual(true, eventFired);
+  testing.expectEqual(fd, receivedFormData);
+}
+</script>
+
+<script id=formDataEventNotFiredWithoutForm>
+{
+  // formdata event should NOT fire when FormData is constructed without a form
+  const fd = new FormData();
+  fd.append('a', '1');
+  testing.expectEqual('1', fd.get('a'));
+}
+</script>
+
+<script id=formDataEventBubbles>
+{
+  // formdata event should bubble
+  const container = document.createElement('div');
+  const form = document.createElement('form');
+  container.appendChild(form);
+  document.body.appendChild(container);
+
+  const input = document.createElement('input');
+  input.name = 'x';
+  input.value = '1';
+  form.appendChild(input);
+
+  let bubbled = false;
+  container.addEventListener('formdata', () => {
+    bubbled = true;
+  });
+
+  const fd = new FormData(form);
+  testing.expectEqual(true, bubbled);
+
+  document.body.removeChild(container);
+}
+</script>
+
+<script id=formDataEventNotCancelable>
+{
+  // formdata event should not be cancelable
+  const form = document.createElement('form');
+
+  const input = document.createElement('input');
+  input.name = 'key';
+  input.value = 'val';
+  form.appendChild(input);
+
+  let cancelable = null;
+  form.addEventListener('formdata', (e) => {
+    cancelable = e.cancelable;
+  });
+
+  const fd = new FormData(form);
+  testing.expectEqual(false, cancelable);
+}
+</script>
+
+<script id=formDataEventModifyFormData>
+{
+  // Listeners can modify formData during the event
+  const form = document.createElement('form');
+
+  const input = document.createElement('input');
+  input.name = 'original';
+  input.value = 'data';
+  form.appendChild(input);
+
+  form.addEventListener('formdata', (e) => {
+    e.formData.append('added', 'by-listener');
+  });
+
+  const fd = new FormData(form);
+  testing.expectEqual('data', fd.get('original'));
+  testing.expectEqual('by-listener', fd.get('added'));
+}
+</script>

src/browser/tests/url.html

@@ -871,33 +871,3 @@
     testing.expectEqual('', url.search);
   }
 </script>
-
-<script id="SOP Bypass">
-  {
-    const url = new URL('http://example.com/@bank.com');
-    testing.expectEqual('http:', url.protocol);
-    testing.expectEqual('example.com', url.hostname);
-    testing.expectEqual('', url.port);
-    testing.expectEqual('http://example.com', url.origin);
-    testing.expectEqual('', url.username);
-    testing.expectEqual('', url.password);
-  }
-  {
-    const url = new URL('http://example.com?@bank.com');
-    testing.expectEqual('http:', url.protocol);
-    testing.expectEqual('example.com', url.hostname);
-    testing.expectEqual('', url.port);
-    testing.expectEqual('http://example.com', url.origin);
-    testing.expectEqual('', url.username);
-    testing.expectEqual('', url.password);
-  }
-  {
-    const url = new URL('http://example.com#@bank.com');
-    testing.expectEqual('http:', url.protocol);
-    testing.expectEqual('example.com', url.hostname);
-    testing.expectEqual('', url.port);
-    testing.expectEqual('http://example.com', url.origin);
-    testing.expectEqual('', url.username);
-    testing.expectEqual('', url.password);
-  }
-</script>

src/browser/webapi/Event.zig

@@ -77,6 +77,7 @@ pub const Type = union(enum) {
     ui_event: *@import("event/UIEvent.zig"),
     promise_rejection_event: *@import("event/PromiseRejectionEvent.zig"),
     submit_event: *@import("event/SubmitEvent.zig"),
+    form_data_event: *@import("event/FormDataEvent.zig"),
 };
 
 pub const Options = struct {
@@ -176,6 +177,7 @@ pub fn is(self: *Event, comptime T: type) ?*T {
         .pop_state_event => |e| return if (T == @import("event/PopStateEvent.zig")) e else null,
         .promise_rejection_event => |e| return if (T == @import("event/PromiseRejectionEvent.zig")) e else null,
         .submit_event => |e| return if (T == @import("event/SubmitEvent.zig")) e else null,
+        .form_data_event => |e| return if (T == @import("event/FormDataEvent.zig")) e else null,
         .ui_event => |e| {
             if (T == @import("event/UIEvent.zig")) {
                 return e;

src/browser/webapi/ResizeObserver.zig

@@ -62,5 +62,6 @@ pub const JsApi = struct {
 
     pub const constructor = bridge.constructor(ResizeObserver.init, .{});
     pub const observe = bridge.function(ResizeObserver.observe, .{});
+    pub const unobserve = bridge.function(ResizeObserver.unobserve, .{});
     pub const disconnect = bridge.function(ResizeObserver.disconnect, .{});
 };

src/browser/webapi/canvas/CanvasRenderingContext2D.zig

@@ -23,16 +23,24 @@ const js = @import("../../js/js.zig");
 const color = @import("../../color.zig");
 const Page = @import("../../Page.zig");
 
+const Canvas = @import("../element/html/Canvas.zig");
 const ImageData = @import("../ImageData.zig");
 
 /// This class doesn't implement a `constructor`.
 /// It can be obtained with a call to `HTMLCanvasElement#getContext`.
 /// https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D
 const CanvasRenderingContext2D = @This();
+/// Reference to the parent canvas element.
+/// https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/canvas
+_canvas: *Canvas,
 /// Fill color.
 /// TODO: Add support for `CanvasGradient` and `CanvasPattern`.
 _fill_style: color.RGBA = color.RGBA.Named.black,
 
+pub fn getCanvas(self: *const CanvasRenderingContext2D) *Canvas {
+    return self._canvas;
+}
+
 pub fn getFillStyle(self: *const CanvasRenderingContext2D, page: *Page) ![]const u8 {
     var w = std.Io.Writer.Allocating.init(page.call_arena);
     try self._fill_style.format(&w.writer);
@@ -125,6 +133,7 @@ pub const JsApi = struct {
         pub var class_id: bridge.ClassId = undefined;
     };
 
+    pub const canvas = bridge.accessor(CanvasRenderingContext2D.getCanvas, null, .{});
     pub const font = bridge.property("10px sans-serif", .{ .template = false, .readonly = false });
     pub const globalAlpha = bridge.property(1.0, .{ .template = false, .readonly = false });
     pub const globalCompositeOperation = bridge.property("source-over", .{ .template = false, .readonly = false });

src/browser/webapi/element/html/Canvas.zig

@@ -67,9 +67,9 @@ const DrawingContext = union(enum) {
     webgl: *WebGLRenderingContext,
 };
 
-pub fn getContext(_: *Canvas, context_type: []const u8, page: *Page) !?DrawingContext {
+pub fn getContext(self: *Canvas, context_type: []const u8, page: *Page) !?DrawingContext {
     if (std.mem.eql(u8, context_type, "2d")) {
-        const ctx = try page._factory.create(CanvasRenderingContext2D{});
+        const ctx = try page._factory.create(CanvasRenderingContext2D{ ._canvas = self });
         return .{ .@"2d" = ctx };
     }
 

src/browser/webapi/event/FormDataEvent.zig

@@ -0,0 +1,95 @@
+// Copyright (C) 2023-2026 Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const String = @import("../../../string.zig").String;
+const Page = @import("../../Page.zig");
+const Session = @import("../../Session.zig");
+const js = @import("../../js/js.zig");
+
+const Event = @import("../Event.zig");
+const UIEvent = @import("UIEvent.zig");
+
+const FormData = @import("../net/FormData.zig");
+
+/// https://developer.mozilla.org/en-US/docs/Web/API/FormDataEvent
+const FormDataEvent = @This();
+
+_proto: *Event,
+_form_data: ?*FormData = null,
+
+const Options = Event.inheritOptions(FormDataEvent, struct {
+    formData: ?*FormData = null,
+});
+
+pub fn init(typ: []const u8, maybe_options: Options, page: *Page) !*FormDataEvent {
+    const arena = try page.getArena(.{ .debug = "FormDataEvent" });
+    errdefer page.releaseArena(arena);
+    const type_string = try String.init(arena, typ, .{});
+    return initWithTrusted(arena, type_string, maybe_options, false, page);
+}
+
+pub fn initTrusted(typ: String, _opts: ?Options, page: *Page) !*FormDataEvent {
+    const arena = try page.getArena(.{ .debug = "FormDataEvent.trusted" });
+    errdefer page.releaseArena(arena);
+    return initWithTrusted(arena, typ, _opts, true, page);
+}
+
+fn initWithTrusted(arena: Allocator, typ: String, maybe_options: ?Options, trusted: bool, page: *Page) !*FormDataEvent {
+    const options = maybe_options orelse Options{};
+
+    const event = try page._factory.event(
+        arena,
+        typ,
+        FormDataEvent{
+            ._proto = undefined,
+            ._form_data = options.formData,
+        },
+    );
+
+    Event.populatePrototypes(event, options, trusted);
+    return event;
+}
+
+pub fn deinit(self: *FormDataEvent, shutdown: bool, session: *Session) void {
+    self._proto.deinit(shutdown, session);
+}
+
+pub fn asEvent(self: *FormDataEvent) *Event {
+    return self._proto;
+}
+
+pub fn getFormData(self: *const FormDataEvent) ?*FormData {
+    return self._form_data;
+}
+
+pub const JsApi = struct {
+    pub const bridge = js.Bridge(FormDataEvent);
+
+    pub const Meta = struct {
+        pub const name = "FormDataEvent";
+        pub const prototype_chain = bridge.prototypeChain();
+        pub var class_id: bridge.ClassId = undefined;
+        pub const weak = true;
+        pub const finalizer = bridge.finalizer(FormDataEvent.deinit);
+    };
+
+    pub const constructor = bridge.constructor(FormDataEvent.init, .{});
+    pub const formData = bridge.accessor(FormDataEvent.getFormData, null, .{});
+};

src/browser/webapi/event/SubmitEvent.zig

@@ -26,7 +26,7 @@ const Event = @import("../Event.zig");
 const HtmlElement = @import("../element/Html.zig");
 const Allocator = std.mem.Allocator;
 
-// https://developer.mozilla.org/en-US/docs/Web/API/SubmitEvent
+/// https://developer.mozilla.org/en-US/docs/Web/API/SubmitEvent
 const SubmitEvent = @This();
 
 _proto: *Event,

src/browser/webapi/net/FormData.zig

@@ -35,10 +35,22 @@ _arena: Allocator,
 _list: KeyValueList,
 
 pub fn init(form: ?*Form, submitter: ?*Element, page: *Page) !*FormData {
-    return page._factory.create(FormData{
+    const form_data = try page._factory.create(FormData{
         ._arena = page.arena,
         ._list = try collectForm(page.arena, form, submitter, page),
     });
+
+    // Dispatch `formdata` event if form provided.
+    if (form) |_form| {
+        const form_data_event = try (@import("../event/FormDataEvent.zig")).initTrusted(
+            comptime .wrap("formdata"),
+            .{ .bubbles = true, .cancelable = false, .formData = form_data },
+            page,
+        );
+        try page._event_manager.dispatch(_form.asNode().asEventTarget(), form_data_event.asEvent());
+    }
+
+    return form_data;
 }
 
 pub fn get(self: *const FormData, name: []const u8) ?[]const u8 {

src/cdp/domains/lp.zig

@@ -135,17 +135,10 @@ fn getInteractiveElements(cmd: anytype) !void {
         page.document.asNode();
 
     const elements = try interactive.collectInteractiveElements(root, cmd.arena, page);
-
-    // Register nodes so nodeIds are valid for subsequent CDP calls.
-    var node_ids: std.ArrayList(Node.Id) = try .initCapacity(cmd.arena, elements.len);
-    for (elements) |el| {
-        const registered = try bc.node_registry.register(el.node);
-        node_ids.appendAssumeCapacity(registered.id);
-    }
+    try interactive.registerNodes(elements, &bc.node_registry);
 
     return cmd.sendResult(.{
         .elements = elements,
-        .nodeIds = node_ids.items,
     }, .{});
 }
 
@@ -308,7 +301,6 @@ test "cdp.lp: getInteractiveElements" {
 
     const result = (try ctx.getSentMessage(0)).?.object.get("result").?.object;
     try testing.expect(result.get("elements") != null);
-    try testing.expect(result.get("nodeIds") != null);
 }
 
 test "cdp.lp: getStructuredData" {

src/html5ever/lib.rs

@@ -158,13 +158,13 @@ pub extern "C" fn html5ever_attribute_iterator_next(
 
     let attr = &iter.vec[pos];
     iter.pos += 1;
-    return CNullable::<CAttribute>::some(CAttribute {
+    CNullable::<CAttribute>::some(CAttribute {
         name: CQualName::create(&attr.name),
         value: StringSlice {
             ptr: attr.value.as_ptr(),
             len: attr.value.len(),
         },
-    });
+    })
 }
 
 #[no_mangle]
@@ -186,12 +186,12 @@ pub extern "C" fn html5ever_get_memory_usage() -> Memory {
     use tikv_jemalloc_ctl::{epoch, stats};
 
     // many statistics are cached and only updated when the epoch is advanced.
-    epoch::advance().unwrap();
+    drop(epoch::advance());
 
-    return Memory {
-        resident: stats::resident::read().unwrap(),
-        allocated: stats::allocated::read().unwrap(),
-    };
+    Memory {
+        resident: stats::resident::read().unwrap_or(0),
+        allocated: stats::allocated::read().unwrap_or(0),
+    }
 }
 
 // Streaming parser API
@@ -325,7 +325,7 @@ pub extern "C" fn html5ever_streaming_parser_destroy(parser_ptr: *mut c_void) {
     // Drop the parser box without finishing
     // This is for cases where you want to cancel parsing
     unsafe {
-        let _ = Box::from_raw(parser_ptr as *mut StreamingParser);
+        drop(Box::from_raw(parser_ptr as *mut StreamingParser));
     }
 }
 

src/html5ever/sink.rs

@@ -36,10 +36,10 @@ pub struct ElementData {
 }
 impl ElementData {
     fn new(qname: QualName, flags: ElementFlags) -> Self {
-        return Self {
+        Self {
             qname: qname,
             mathml_annotation_xml_integration_point: flags.mathml_annotation_xml_integration_point,
-        };
+        }
     }
 }
 
@@ -130,12 +130,12 @@ impl<'arena> TreeSink for Sink<'arena> {
         unsafe {
             let mut attribute_iterator = CAttributeIterator { vec: attrs, pos: 0 };
 
-            return (self.create_element_callback)(
+            (self.create_element_callback)(
                 self.ctx,
                 data as *mut _ as *mut c_void,
                 CQualName::create(&name),
                 &mut attribute_iterator as *mut _ as *mut c_void,
-            );
+            )
         }
     }
 

src/html5ever/types.rs

@@ -126,21 +126,21 @@ impl CQualName {
             None => CNullable::<StringSlice>::none(),
             Some(prefix) => CNullable::<StringSlice>::some(StringSlice { ptr: prefix.as_ptr(), len: prefix.len()}),
         };
-        return CQualName{
+        CQualName{
             // inner: q as *const _ as *const c_void,
             ns: ns,
             local: local,
             prefix: prefix,
-        };
+        }
     }
 }
 impl Default for CQualName {
     fn default() -> Self {
-        return Self{
+        Self{
             prefix: CNullable::<StringSlice>::none(),
             ns: StringSlice::default(),
             local: StringSlice::default(),
-        };
+        }
     }
 }
 

src/lightpanda.zig

@@ -35,6 +35,7 @@ pub const markdown = @import("browser/markdown.zig");
 pub const SemanticTree = @import("SemanticTree.zig");
 pub const CDPNode = @import("cdp/Node.zig");
 pub const interactive = @import("browser/interactive.zig");
+pub const links = @import("browser/links.zig");
 pub const forms = @import("browser/forms.zig");
 pub const actions = @import("browser/actions.zig");
 pub const structured_data = @import("browser/structured_data.zig");

src/mcp/resources.zig

@@ -22,12 +22,14 @@ pub const resource_list = [_]protocol.Resource{
 };
 
 pub fn handleList(server: *Server, req: protocol.Request) !void {
-    try server.sendResult(req.id.?, .{ .resources = &resource_list });
+    const id = req.id orelse return;
+    try server.sendResult(id, .{ .resources = &resource_list });
 }
 
 const ReadParams = struct {
     uri: []const u8,
 };
+const Format = enum { html, markdown };
 
 const ResourceStreamingResult = struct {
     contents: []const struct {
@@ -38,7 +40,7 @@ const ResourceStreamingResult = struct {
 
     const StreamingText = struct {
         page: *lp.Page,
-        format: enum { html, markdown },
+        format: Format,
 
         pub fn jsonStringify(self: @This(), jw: *std.json.Stringify) !void {
             try jw.beginWriteRaw();
@@ -47,9 +49,11 @@ const ResourceStreamingResult = struct {
             switch (self.format) {
                 .html => lp.dump.root(self.page.document, .{}, &escaped.writer, self.page) catch |err| {
                     log.err(.mcp, "html dump failed", .{ .err = err });
+                    return error.WriteFailed;
                 },
                 .markdown => lp.markdown.dump(self.page.document.asNode(), .{}, &escaped.writer, self.page) catch |err| {
                     log.err(.mcp, "markdown dump failed", .{ .err = err });
+                    return error.WriteFailed;
                 },
             }
             try jw.writer.writeByte('"');
@@ -86,28 +90,25 @@ pub fn handleRead(server: *Server, arena: std.mem.Allocator, req: protocol.Reque
         return server.sendError(req_id, .PageNotLoaded, "Page not loaded");
     };
 
-    switch (uri) {
-        .@"mcp://page/html" => {
-            const result: ResourceStreamingResult = .{
-                .contents = &.{.{
-                    .uri = params.uri,
-                    .mimeType = "text/html",
-                    .text = .{ .page = page, .format = .html },
-                }},
-            };
-            try server.sendResult(req_id, result);
-        },
-        .@"mcp://page/markdown" => {
-            const result: ResourceStreamingResult = .{
-                .contents = &.{.{
-                    .uri = params.uri,
-                    .mimeType = "text/markdown",
-                    .text = .{ .page = page, .format = .markdown },
-                }},
-            };
-            try server.sendResult(req_id, result);
-        },
-    }
+    const format: Format = switch (uri) {
+        .@"mcp://page/html" => .html,
+        .@"mcp://page/markdown" => .markdown,
+    };
+    const mime_type: []const u8 = switch (uri) {
+        .@"mcp://page/html" => "text/html",
+        .@"mcp://page/markdown" => "text/markdown",
+    };
+
+    const result: ResourceStreamingResult = .{
+        .contents = &.{.{
+            .uri = params.uri,
+            .mimeType = mime_type,
+            .text = .{ .page = page, .format = format },
+        }},
+    };
+    server.sendResult(req_id, result) catch {
+        return server.sendError(req_id, .InternalError, "Failed to serialize resource content");
+    };
 }
 
 const testing = @import("../testing.zig");

src/mcp/router.zig

@@ -16,6 +16,7 @@ pub fn processRequests(server: *Server, reader: *std.io.Reader) !void {
         const buffered_line = reader.takeDelimiter('\n') catch |err| switch (err) {
             error.StreamTooLong => {
                 log.err(.mcp, "Message too long", .{});
+                try server.sendError(.null, .InvalidRequest, "Message too long");
                 continue;
             },
             else => return err,
@@ -80,6 +81,7 @@ pub fn handleMessage(server: *Server, arena: std.mem.Allocator, msg: []const u8)
 }
 
 fn handleInitialize(server: *Server, req: protocol.Request) !void {
+    const id = req.id orelse return;
     const result = protocol.InitializeResult{
         .protocolVersion = "2025-11-25",
         .capabilities = .{
@@ -92,7 +94,7 @@ fn handleInitialize(server: *Server, req: protocol.Request) !void {
         },
     };
 
-    try server.sendResult(req.id.?, result);
+    try server.sendResult(id, result);
 }
 
 fn handlePing(server: *Server, req: protocol.Request) !void {

src/mcp/tools.zig

@@ -172,13 +172,18 @@ pub const tool_list = [_]protocol.Tool{
 
 pub fn handleList(server: *Server, arena: std.mem.Allocator, req: protocol.Request) !void {
     _ = arena;
-    try server.sendResult(req.id.?, .{ .tools = &tool_list });
+    const id = req.id orelse return;
+    try server.sendResult(id, .{ .tools = &tool_list });
 }
 
 const GotoParams = struct {
     url: [:0]const u8,
 };
 
+const UrlParams = struct {
+    url: ?[:0]const u8 = null,
+};
+
 const EvaluateParams = struct {
     script: [:0]const u8,
     url: ?[:0]const u8 = null,
@@ -201,28 +206,18 @@ const ToolStreamingText = struct {
         switch (self.action) {
             .markdown => lp.markdown.dump(self.page.document.asNode(), .{}, w, self.page) catch |err| {
                 log.err(.mcp, "markdown dump failed", .{ .err = err });
+                return error.WriteFailed;
             },
             .links => {
-                if (Selector.querySelectorAll(self.page.document.asNode(), "a[href]", self.page)) |list| {
-                    defer list.deinit(self.page._session);
-
-                    var first = true;
-                    for (list._nodes) |node| {
-                        if (node.is(Element.Html.Anchor)) |anchor| {
-                            const href = anchor.getHref(self.page) catch |err| {
-                                log.err(.mcp, "resolve href failed", .{ .err = err });
-                                continue;
-                            };
-
-                            if (href.len > 0) {
-                                if (!first) try w.writeByte('\n');
-                                try w.writeAll(href);
-                                first = false;
-                            }
-                        }
-                    }
-                } else |err| {
+                const links = lp.links.collectLinks(self.page.call_arena, self.page.document.asNode(), self.page) catch |err| {
                     log.err(.mcp, "query links failed", .{ .err = err });
+                    return error.WriteFailed;
+                };
+                var first = true;
+                for (links) |href| {
+                    if (!first) try w.writeByte('\n');
+                    try w.writeAll(href);
+                    first = false;
                 }
             },
             .semantic_tree => {
@@ -248,6 +243,7 @@ const ToolStreamingText = struct {
 
                 st.textStringify(w) catch |err| {
                     log.err(.mcp, "semantic tree dump failed", .{ .err = err });
+                    return error.WriteFailed;
                 };
             },
         }
@@ -324,7 +320,7 @@ pub fn handleCall(server: *Server, arena: std.mem.Allocator, req: protocol.Reque
 }
 
 fn handleGoto(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const args = try parseArguments(GotoParams, arena, arguments, server, id, "goto");
+    const args = try parseArgs(GotoParams, arena, arguments, server, id, "goto");
     try performGoto(server, args.url, id);
 
     const content = [_]protocol.TextContent([]const u8){.{ .text = "Navigated successfully." }};
@@ -332,45 +328,27 @@ fn handleGoto(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arg
 }
 
 fn handleMarkdown(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const MarkdownParams = struct {
-        url: ?[:0]const u8 = null,
-    };
-    if (arguments) |args_raw| {
-        if (std.json.parseFromValueLeaky(MarkdownParams, arena, args_raw, .{ .ignore_unknown_fields = true })) |args| {
-            if (args.url) |u| {
-                try performGoto(server, u, id);
-            }
-        } else |_| {}
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(UrlParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const content = [_]protocol.TextContent(ToolStreamingText){.{
         .text = .{ .page = page, .action = .markdown },
     }};
-    try server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content });
+    server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content }) catch {
+        return server.sendError(id, .InternalError, "Failed to serialize markdown content");
+    };
 }
 
 fn handleLinks(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const LinksParams = struct {
-        url: ?[:0]const u8 = null,
-    };
-    if (arguments) |args_raw| {
-        if (std.json.parseFromValueLeaky(LinksParams, arena, args_raw, .{ .ignore_unknown_fields = true })) |args| {
-            if (args.url) |u| {
-                try performGoto(server, u, id);
-            }
-        } else |_| {}
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(UrlParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const content = [_]protocol.TextContent(ToolStreamingText){.{
         .text = .{ .page = page, .action = .links },
     }};
-    try server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content });
+    server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content }) catch {
+        return server.sendError(id, .InternalError, "Failed to serialize links content");
+    };
 }
 
 fn handleSemanticTree(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
@@ -379,44 +357,38 @@ fn handleSemanticTree(server: *Server, arena: std.mem.Allocator, id: std.json.Va
         backendNodeId: ?u32 = null,
         maxDepth: ?u32 = null,
     };
-    var tree_args: TreeParams = .{};
-    if (arguments) |args_raw| {
-        if (std.json.parseFromValueLeaky(TreeParams, arena, args_raw, .{ .ignore_unknown_fields = true })) |args| {
-            tree_args = args;
-            if (args.url) |u| {
-                try performGoto(server, u, id);
-            }
-        } else |_| {}
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(TreeParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const content = [_]protocol.TextContent(ToolStreamingText){.{
-        .text = .{ .page = page, .action = .semantic_tree, .registry = &server.node_registry, .arena = arena, .backendNodeId = tree_args.backendNodeId, .maxDepth = tree_args.maxDepth },
+        .text = .{
+            .page = page,
+            .action = .semantic_tree,
+            .registry = &server.node_registry,
+            .arena = arena,
+            .backendNodeId = args.backendNodeId,
+            .maxDepth = args.maxDepth,
+        },
     }};
-    try server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content });
+    server.sendResult(id, protocol.CallToolResult(ToolStreamingText){ .content = &content }) catch {
+        return server.sendError(id, .InternalError, "Failed to serialize semantic tree content");
+    };
 }
 
 fn handleInteractiveElements(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const Params = struct {
-        url: ?[:0]const u8 = null,
-    };
-    if (arguments) |args_raw| {
-        if (std.json.parseFromValueLeaky(Params, arena, args_raw, .{ .ignore_unknown_fields = true })) |args| {
-            if (args.url) |u| {
-                try performGoto(server, u, id);
-            }
-        } else |_| {}
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(UrlParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const elements = lp.interactive.collectInteractiveElements(page.document.asNode(), arena, page) catch |err| {
         log.err(.mcp, "elements collection failed", .{ .err = err });
         return server.sendError(id, .InternalError, "Failed to collect interactive elements");
     };
+
+    lp.interactive.registerNodes(elements, &server.node_registry) catch |err| {
+        log.err(.mcp, "node registration failed", .{ .err = err });
+        return server.sendError(id, .InternalError, "Failed to register element nodes");
+    };
+
     var aw: std.Io.Writer.Allocating = .init(arena);
     try std.json.Stringify.value(elements, .{}, &aw.writer);
 
@@ -425,19 +397,8 @@ fn handleInteractiveElements(server: *Server, arena: std.mem.Allocator, id: std.
 }
 
 fn handleStructuredData(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const Params = struct {
-        url: ?[:0]const u8 = null,
-    };
-    if (arguments) |args_raw| {
-        if (std.json.parseFromValueLeaky(Params, arena, args_raw, .{ .ignore_unknown_fields = true })) |args| {
-            if (args.url) |u| {
-                try performGoto(server, u, id);
-            }
-        } else |_| {}
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(UrlParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const data = lp.structured_data.collectStructuredData(page.document.asNode(), arena, page) catch |err| {
         log.err(.mcp, "struct data collection failed", .{ .err = err });
@@ -451,20 +412,8 @@ fn handleStructuredData(server: *Server, arena: std.mem.Allocator, id: std.json.
 }
 
 fn handleDetectForms(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const Params = struct {
-        url: ?[:0]const u8 = null,
-    };
-    if (arguments) |args_raw| {
-        const args = std.json.parseFromValueLeaky(Params, arena, args_raw, .{ .ignore_unknown_fields = true }) catch {
-            return server.sendError(id, .InvalidParams, "Invalid arguments for detectForms");
-        };
-        if (args.url) |u| {
-            try performGoto(server, u, id);
-        }
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgsOrDefault(UrlParams, arena, arguments, server, id);
+    const page = try ensurePage(server, id, args.url);
 
     const forms_data = lp.forms.collectForms(arena, page.document.asNode(), page) catch |err| {
         log.err(.mcp, "form collection failed", .{ .err = err });
@@ -484,14 +433,8 @@ fn handleDetectForms(server: *Server, arena: std.mem.Allocator, id: std.json.Val
 }
 
 fn handleEvaluate(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
-    const args = try parseArguments(EvaluateParams, arena, arguments, server, id, "evaluate");
-
-    if (args.url) |url| {
-        try performGoto(server, url, id);
-    }
-    const page = server.session.currentPage() orelse {
-        return server.sendError(id, .PageNotLoaded, "Page not loaded");
-    };
+    const args = try parseArgs(EvaluateParams, arena, arguments, server, id, "evaluate");
+    const page = try ensurePage(server, id, args.url);
 
     var ls: js.Local.Scope = undefined;
     page.js.localScope(&ls);
@@ -520,7 +463,7 @@ fn handleClick(server: *Server, arena: std.mem.Allocator, id: std.json.Value, ar
     const ClickParams = struct {
         backendNodeId: CDPNode.Id,
     };
-    const args = try parseArguments(ClickParams, arena, arguments, server, id, "click");
+    const args = try parseArgs(ClickParams, arena, arguments, server, id, "click");
 
     const page = server.session.currentPage() orelse {
         return server.sendError(id, .PageNotLoaded, "Page not loaded");
@@ -552,7 +495,7 @@ fn handleFill(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arg
         backendNodeId: CDPNode.Id,
         text: []const u8,
     };
-    const args = try parseArguments(FillParams, arena, arguments, server, id, "fill");
+    const args = try parseArgs(FillParams, arena, arguments, server, id, "fill");
 
     const page = server.session.currentPage() orelse {
         return server.sendError(id, .PageNotLoaded, "Page not loaded");
@@ -586,7 +529,7 @@ fn handleScroll(server: *Server, arena: std.mem.Allocator, id: std.json.Value, a
         x: ?i32 = null,
         y: ?i32 = null,
     };
-    const args = try parseArguments(ScrollParams, arena, arguments, server, id, "scroll");
+    const args = try parseArgs(ScrollParams, arena, arguments, server, id, "scroll");
 
     const page = server.session.currentPage() orelse {
         return server.sendError(id, .PageNotLoaded, "Page not loaded");
@@ -623,7 +566,7 @@ fn handleWaitForSelector(server: *Server, arena: std.mem.Allocator, id: std.json
         selector: [:0]const u8,
         timeout: ?u32 = null,
     };
-    const args = try parseArguments(WaitParams, arena, arguments, server, id, "waitForSelector");
+    const args = try parseArgs(WaitParams, arena, arguments, server, id, "waitForSelector");
 
     _ = server.session.currentPage() orelse {
         return server.sendError(id, .PageNotLoaded, "Page not loaded");
@@ -647,12 +590,38 @@ fn handleWaitForSelector(server: *Server, arena: std.mem.Allocator, id: std.json
     return server.sendResult(id, protocol.CallToolResult([]const u8){ .content = &content });
 }
 
-fn parseArguments(comptime T: type, arena: std.mem.Allocator, arguments: ?std.json.Value, server: *Server, id: std.json.Value, tool_name: []const u8) !T {
-    if (arguments == null) {
+fn ensurePage(server: *Server, id: std.json.Value, url: ?[:0]const u8) !*lp.Page {
+    if (url) |u| {
+        try performGoto(server, u, id);
+    }
+    return server.session.currentPage() orelse {
+        try server.sendError(id, .PageNotLoaded, "Page not loaded");
+        return error.PageNotLoaded;
+    };
+}
+
+/// Parses JSON arguments into a given struct type `T`.
+/// If the arguments are missing, it returns a default-initialized `T` (e.g., `.{}`).
+/// If the arguments are present but invalid, it sends an MCP error response and returns `error.InvalidParams`.
+/// Use this for tools where all arguments are optional.
+fn parseArgsOrDefault(comptime T: type, arena: std.mem.Allocator, arguments: ?std.json.Value, server: *Server, id: std.json.Value) !T {
+    const args_raw = arguments orelse return .{};
+    return std.json.parseFromValueLeaky(T, arena, args_raw, .{ .ignore_unknown_fields = true }) catch {
+        try server.sendError(id, .InvalidParams, "Invalid arguments");
+        return error.InvalidParams;
+    };
+}
+
+/// Parses JSON arguments into a given struct type `T`.
+/// If the arguments are missing or invalid, it automatically sends an MCP error response to the client
+/// and returns an `error.InvalidParams`.
+/// Use this for tools that require strict validation or mandatory arguments.
+fn parseArgs(comptime T: type, arena: std.mem.Allocator, arguments: ?std.json.Value, server: *Server, id: std.json.Value, tool_name: []const u8) !T {
+    const args_raw = arguments orelse {
         try server.sendError(id, .InvalidParams, "Missing arguments");
         return error.InvalidParams;
-    }
-    return std.json.parseFromValueLeaky(T, arena, arguments.?, .{ .ignore_unknown_fields = true }) catch {
+    };
+    return std.json.parseFromValueLeaky(T, arena, args_raw, .{ .ignore_unknown_fields = true }) catch {
         const msg = std.fmt.allocPrint(arena, "Invalid arguments for {s}", .{tool_name}) catch "Invalid arguments";
         try server.sendError(id, .InvalidParams, msg);
         return error.InvalidParams;
@@ -664,7 +633,10 @@ fn performGoto(server: *Server, url: [:0]const u8, id: std.json.Value) !void {
     if (session.page != null) {
         session.removePage();
     }
-    const page = try session.createPage();
+    const page = session.createPage() catch {
+        try server.sendError(id, .InternalError, "Failed to create page");
+        return error.NavigationFailed;
+    };
     page.navigate(url, .{
         .reason = .address_bar,
         .kind = .{ .push = null },
@@ -673,8 +645,14 @@ fn performGoto(server: *Server, url: [:0]const u8, id: std.json.Value) !void {
         return error.NavigationFailed;
     };
 
-    var runner = try session.runner(.{});
-    try runner.wait(.{ .ms = 2000 });
+    var runner = session.runner(.{}) catch {
+        try server.sendError(id, .InternalError, "Failed to start page runner");
+        return error.NavigationFailed;
+    };
+    runner.wait(.{ .ms = 2000 }) catch {
+        try server.sendError(id, .InternalError, "Timeout waiting for page load");
+        return error.NavigationFailed;
+    };
 }
 
 const router = @import("router.zig");