fix: add readability fallback extraction

src/agents/tools/web-fetch-utils.ts

@@ -81,6 +81,14 @@ export async function extractReadableContent(params: {
   url: string;
   extractMode: ExtractMode;
 }): Promise<{ text: string; title?: string } | null> {
+  const fallback = (): { text: string; title?: string } => {
+    const rendered = htmlToMarkdown(params.html);
+    if (params.extractMode === "text") {
+      const text = markdownToText(rendered.text) || normalizeWhitespace(stripTags(params.html));
+      return { text, title: rendered.title };
+    }
+    return rendered;
+  };
   try {
     const [{ Readability }, { parseHTML }] = await Promise.all([
       import("@mozilla/readability"),
@@ -94,15 +102,15 @@ export async function extractReadableContent(params: {
     }
     const reader = new Readability(document, { charThreshold: 0 });
     const parsed = reader.parse();
-    if (!parsed?.content) return null;
+    if (!parsed?.content) return fallback();
     const title = parsed.title || undefined;
     if (params.extractMode === "text") {
       const text = normalizeWhitespace(parsed.textContent ?? "");
-      return { text, title };
+      return text ? { text, title } : fallback();
     }
     const rendered = htmlToMarkdown(parsed.content);
     return { text: rendered.text, title: title ?? rendered.title };
   } catch {
-    return null;
+    return fallback();
   }
 }