From b3d52c966d9c59836fd168bb43c339ff996a3e87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adri=C3=A0=20Arrufat?= <adria.arrufat@gmail.com>
Date: Sun, 1 Mar 2026 20:23:23 +0900
Subject: [PATCH] mcp: handle errors during resource and tool streaming

---
 src/mcp/resources.zig | 13 +++++++++----
 src/mcp/tools.zig     | 26 ++++++++++++++------------
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/src/mcp/resources.zig b/src/mcp/resources.zig
index d5f16770..9742800b 100644
--- a/src/mcp/resources.zig
+++ b/src/mcp/resources.zig
@@ -1,6 +1,7 @@
 const std = @import("std");
 
 const lp = @import("lightpanda");
+const log = lp.log;
 
 const protocol = @import("protocol.zig");
 const Server = @import("Server.zig");
@@ -58,8 +59,12 @@ const ResourceStreamingResult = struct {
             try jw.writer.writeByte('"');
             var escaped = protocol.JsonEscapingWriter.init(jw.writer);
             switch (self.format) {
-                .html => try lp.dump.root(self.server.page.document, .{}, &escaped.writer, self.server.page),
-                .markdown => try lp.markdown.dump(self.server.page.document.asNode(), .{}, &escaped.writer, self.server.page),
+                .html => lp.dump.root(self.server.page.document, .{}, &escaped.writer, self.server.page) catch |err| {
+                    log.err(.mcp, "html dump failed", .{ .err = err });
+                },
+                .markdown => lp.markdown.dump(self.server.page.document.asNode(), .{}, &escaped.writer, self.server.page) catch |err| {
+                    log.err(.mcp, "markdown dump failed", .{ .err = err });
+                },
             }
             try jw.writer.writeByte('"');
             jw.endWriteRaw();
@@ -79,7 +84,7 @@ pub fn handleRead(server: *Server, arena: std.mem.Allocator, req: protocol.Reque
     };
 
     if (std.mem.eql(u8, params.uri, "mcp://page/html")) {
-        const result = ResourceStreamingResult{
+        const result: ResourceStreamingResult = .{
             .contents = &.{.{
                 .uri = params.uri,
                 .mimeType = "text/html",
@@ -88,7 +93,7 @@ pub fn handleRead(server: *Server, arena: std.mem.Allocator, req: protocol.Reque
         };
         try sendResult(server, req.id.?, result);
     } else if (std.mem.eql(u8, params.uri, "mcp://page/markdown")) {
-        const result = ResourceStreamingResult{
+        const result: ResourceStreamingResult = .{
             .contents = &.{.{
                 .uri = params.uri,
                 .mimeType = "text/markdown",
diff --git a/src/mcp/tools.zig b/src/mcp/tools.zig
index 80253a6a..0b1de596 100644
--- a/src/mcp/tools.zig
+++ b/src/mcp/tools.zig
@@ -126,21 +126,23 @@ const ToolStreamingText = struct {
         var escaped = protocol.JsonEscapingWriter.init(jw.writer);
         const w = &escaped.writer;
         switch (self.action) {
-            .markdown => try lp.markdown.dump(self.server.page.document.asNode(), .{}, w, self.server.page),
+            .markdown => lp.markdown.dump(self.server.page.document.asNode(), .{}, w, self.server.page) catch |err| {
+                log.err(.mcp, "markdown dump failed", .{ .err = err });
+            },
             .links => {
-                const list = Selector.querySelectorAll(self.server.page.document.asNode(), "a[href]", self.server.page) catch |err| {
-                    log.err(.mcp, "Error querying links: {s}", .{@errorName(err)});
-                    return;
-                };
-                var first = true;
-                for (list._nodes) |node| {
-                    if (node.is(Element)) |el| {
-                        if (el.getAttributeSafe(String.wrap("href"))) |href| {
-                            if (!first) try w.writeByte('\n');
-                            try w.writeAll(href);
-                            first = false;
+                if (Selector.querySelectorAll(self.server.page.document.asNode(), "a[href]", self.server.page)) |list| {
+                    var first = true;
+                    for (list._nodes) |node| {
+                        if (node.is(Element)) |el| {
+                            if (el.getAttributeSafe(String.wrap("href"))) |href| {
+                                if (!first) try w.writeByte('\n');
+                                try w.writeAll(href);
+                                first = false;
+                            }
                         }
                     }
+                } else |err| {
+                    log.err(.mcp, "query links failed", .{ .err = err });
                 }
             },
         }