fix(discord): render bare URLs as bare links, not masked links. (#567)

## Summary

Discord only renders masked links `[text](url)` inside embeds. In a
normal message, a bare URL converted to `[url](url)` shows up as literal
text rather than a clickable link.

In nodeToDiscordMarkdown's link branch, return the bare URL when the
link's label equals its target (the bare-URL / autolink case); labeled
links are unchanged. Adds regression tests for both bare URLs and
<autolinks>.

Fixes #565.

Author: furgin

.changeset/discord-bare-url-links.md

@@ -0,0 +1,5 @@
+---
+"@chat-adapter/discord": patch
+---
+
+fix: render bare URLs and autolinks as bare URLs instead of `[url](url)` masked links, which Discord only renders inside embeds (in normal messages they showed up as literal text)

packages/adapter-discord/src/markdown.test.ts

@@ -29,6 +29,26 @@ describe("DiscordFormatConverter", () => {
       expect(result).toContain("[link text](https://example.com)");
     });
 
+    it("should render a bare URL as a bare URL, not a masked link", () => {
+      // Discord renders masked links `[text](url)` only in embeds, so wrapping
+      // a bare URL as `[url](url)` shows up as literal text in a normal message.
+      const ast = converter.toAst("https://example.com");
+      const result = converter.fromAst(ast);
+      expect(result).toContain("https://example.com");
+      expect(result).not.toContain(
+        "[https://example.com](https://example.com)"
+      );
+    });
+
+    it("should render an autolink as a bare URL, not a masked link", () => {
+      const ast = converter.toAst("<https://example.com>");
+      const result = converter.fromAst(ast);
+      expect(result).toContain("https://example.com");
+      expect(result).not.toContain(
+        "[https://example.com](https://example.com)"
+      );
+    });
+
     it("should preserve inline code", () => {
       const ast = converter.toAst("Use `const x = 1`");
       const result = converter.fromAst(ast);

packages/adapter-discord/src/markdown.ts

@@ -155,6 +155,12 @@ export class DiscordFormatConverter extends BaseFormatConverter {
       const linkText = getNodeChildren(node)
         .map((child) => this.nodeToDiscordMarkdown(child))
         .join("");
+      // Bare URLs / autolinks (label === url) must stay bare: Discord only
+      // renders masked links `[text](url)` inside embeds, so `[url](url)` in a
+      // normal message shows up as literal text instead of a clickable link.
+      if (linkText === node.url) {
+        return node.url;
+      }
       // Standard markdown [text](url)
       return `[${linkText}](${node.url})`;
     }