diff --git a/src/browser/tests/mcp_wait_for_selector.html b/src/browser/tests/mcp_wait_for_selector.html
new file mode 100644
index 00000000..111aadaf
--- /dev/null
+++ b/src/browser/tests/mcp_wait_for_selector.html
@@ -0,0 +1,14 @@
+
+
+
+ Already here
+
+
+
diff --git a/src/mcp/tools.zig b/src/mcp/tools.zig
index 51a44476..1e286209 100644
--- a/src/mcp/tools.zig
+++ b/src/mcp/tools.zig
@@ -142,6 +142,20 @@ pub const tool_list = [_]protocol.Tool{
\\}
),
},
+ .{
+ .name = "waitForSelector",
+ .description = "Wait for an element matching a CSS selector to appear in the page. Returns the backend node ID of the matched element.",
+ .inputSchema = protocol.minify(
+ \\{
+ \\ "type": "object",
+ \\ "properties": {
+ \\ "selector": { "type": "string", "description": "The CSS selector to wait for." },
+ \\ "timeout": { "type": "integer", "description": "Optional timeout in milliseconds. Defaults to 5000." }
+ \\ },
+ \\ "required": ["selector"]
+ \\}
+ ),
+ },
};
pub fn handleList(server: *Server, arena: std.mem.Allocator, req: protocol.Request) !void {
@@ -243,6 +257,7 @@ const ToolAction = enum {
click,
fill,
scroll,
+ waitForSelector,
};
const tool_map = std.StaticStringMap(ToolAction).initComptime(.{
@@ -257,6 +272,7 @@ const tool_map = std.StaticStringMap(ToolAction).initComptime(.{
.{ "click", .click },
.{ "fill", .fill },
.{ "scroll", .scroll },
+ .{ "waitForSelector", .waitForSelector },
});
pub fn handleCall(server: *Server, arena: std.mem.Allocator, req: protocol.Request) !void {
@@ -288,6 +304,7 @@ pub fn handleCall(server: *Server, arena: std.mem.Allocator, req: protocol.Reque
.click => try handleClick(server, arena, req.id.?, call_params.arguments),
.fill => try handleFill(server, arena, req.id.?, call_params.arguments),
.scroll => try handleScroll(server, arena, req.id.?, call_params.arguments),
+ .waitForSelector => try handleWaitForSelector(server, arena, req.id.?, call_params.arguments),
}
}
@@ -532,6 +549,42 @@ fn handleScroll(server: *Server, arena: std.mem.Allocator, id: std.json.Value, a
const content = [_]protocol.TextContent([]const u8){.{ .text = "Scrolled successfully." }};
try server.sendResult(id, protocol.CallToolResult([]const u8){ .content = &content });
}
+fn handleWaitForSelector(server: *Server, arena: std.mem.Allocator, id: std.json.Value, arguments: ?std.json.Value) !void {
+ const WaitParams = struct {
+ selector: [:0]const u8,
+ timeout: ?u32 = null,
+ };
+ const args = try parseArguments(WaitParams, arena, arguments, server, id, "waitForSelector");
+
+ const page = server.session.currentPage() orelse {
+ return server.sendError(id, .PageNotLoaded, "Page not loaded");
+ };
+
+ const timeout_ms = args.timeout orelse 5000;
+ var timer = try std.time.Timer.start();
+
+ while (true) {
+ const element = Selector.querySelector(page.document.asNode(), args.selector, page) catch {
+ return server.sendError(id, .InvalidParams, "Invalid selector");
+ };
+
+ if (element) |el| {
+ const registered = try server.node_registry.register(el.asNode());
+ const msg = std.fmt.allocPrint(arena, "Element found. backendNodeId: {d}", .{registered.id}) catch "Element found.";
+
+ const content = [_]protocol.TextContent([]const u8){.{ .text = msg }};
+ return server.sendResult(id, protocol.CallToolResult([]const u8){ .content = &content });
+ }
+
+ const elapsed: u32 = @intCast(timer.read() / std.time.ns_per_ms);
+ if (elapsed >= timeout_ms) {
+ return server.sendError(id, .InternalError, "Timeout waiting for selector");
+ }
+
+ _ = server.session.wait(.{ .timeout_ms = @min(100, timeout_ms - elapsed) });
+ }
+}
+
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) {
try server.sendError(id, .InvalidParams, "Missing arguments");
@@ -670,3 +723,104 @@ test "MCP - Actions: click, fill, scroll" {
try testing.expect(result.isTrue());
}
+
+test "MCP - waitForSelector: existing element" {
+ defer testing.reset();
+ const allocator = testing.allocator;
+ const app = testing.test_app;
+
+ var out_alloc: std.io.Writer.Allocating = .init(testing.arena_allocator);
+ defer out_alloc.deinit();
+
+ var server = try Server.init(allocator, app, &out_alloc.writer);
+ defer server.deinit();
+
+ const aa = testing.arena_allocator;
+ const page = try server.session.createPage();
+ const url = "http://localhost:9582/src/browser/tests/mcp_wait_for_selector.html";
+ try page.navigate(url, .{ .reason = .address_bar, .kind = .{ .push = null } });
+ _ = server.session.wait(.{});
+
+ // waitForSelector on an element that already exists returns immediately
+ const msg =
+ \\{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"waitForSelector","arguments":{"selector":"#existing","timeout":2000}}}
+ ;
+ try router.handleMessage(server, aa, msg);
+
+ try testing.expectJson(
+ \\{
+ \\ "id": 1,
+ \\ "result": {
+ \\ "content": [
+ \\ { "type": "text" }
+ \\ ]
+ \\ }
+ \\}
+ , out_alloc.writer.buffered());
+}
+
+test "MCP - waitForSelector: delayed element" {
+ defer testing.reset();
+ const allocator = testing.allocator;
+ const app = testing.test_app;
+
+ var out_alloc: std.io.Writer.Allocating = .init(testing.arena_allocator);
+ defer out_alloc.deinit();
+
+ var server = try Server.init(allocator, app, &out_alloc.writer);
+ defer server.deinit();
+
+ const aa = testing.arena_allocator;
+ const page = try server.session.createPage();
+ const url = "http://localhost:9582/src/browser/tests/mcp_wait_for_selector.html";
+ try page.navigate(url, .{ .reason = .address_bar, .kind = .{ .push = null } });
+ _ = server.session.wait(.{});
+
+ // waitForSelector on an element added after 200ms via setTimeout
+ const msg =
+ \\{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"waitForSelector","arguments":{"selector":"#delayed","timeout":5000}}}
+ ;
+ try router.handleMessage(server, aa, msg);
+
+ try testing.expectJson(
+ \\{
+ \\ "id": 1,
+ \\ "result": {
+ \\ "content": [
+ \\ { "type": "text" }
+ \\ ]
+ \\ }
+ \\}
+ , out_alloc.writer.buffered());
+}
+
+test "MCP - waitForSelector: timeout" {
+ defer testing.reset();
+ const allocator = testing.allocator;
+ const app = testing.test_app;
+
+ var out_alloc: std.io.Writer.Allocating = .init(testing.arena_allocator);
+ defer out_alloc.deinit();
+
+ var server = try Server.init(allocator, app, &out_alloc.writer);
+ defer server.deinit();
+
+ const aa = testing.arena_allocator;
+ const page = try server.session.createPage();
+ const url = "http://localhost:9582/src/browser/tests/mcp_wait_for_selector.html";
+ try page.navigate(url, .{ .reason = .address_bar, .kind = .{ .push = null } });
+ _ = server.session.wait(.{});
+
+ // waitForSelector with a short timeout on a non-existent element should error
+ const msg =
+ \\{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"waitForSelector","arguments":{"selector":"#nonexistent","timeout":100}}}
+ ;
+ try router.handleMessage(server, aa, msg);
+
+ try testing.expectJson(
+ \\{
+ \\ "id": 1,
+ \\ "error": {}
+ \\}
+ , out_alloc.writer.buffered());
+}