Google Chat adapter emits redundant `<mailto:foo|foo>` / `<tel:n|n>` tokens for autolinked emails and phone numbers

[taslim]

Bug Description

packages/adapter-gchat/src/markdown.ts (nodeToGChat, lines 108–116) collapses link nodes to a bare URL when the link's display text equals the URL — but only for plain http(s):// URLs. For mailto: and tel: links, the URL carries a scheme prefix (mailto:foo@bar.com) that the visible text doesn't (foo@bar.com), so the equality check linkText === node.url never fires, and the adapter emits the verbose <scheme:url|display> form even though display text adds no information.

This is most visible when an agent or upstream message contains plain email addresses. remark-gfm's autolink-literal extension converts bare emails to link nodes [foo@bar.com](mailto:foo@bar.com), and the adapter then ships them to Google Chat as <mailto:foo@bar.com|foo@bar.com>. In some Google Chat clients these render correctly as a clickable email; in others (and consistently when the message text is round-tripped via quotedMessageSnapshot.text, copied to clipboard, or read back by spaces.messages.get), the raw token surfaces in the user-facing text.

The current code at markdown.ts:108–116:

if (isLinkNode(node)) {
  const linkText = getNodeChildren(node)
    .map((child) => this.nodeToGChat(child))
    .join('');
  if (linkText === node.url) {
    return node.url;
  }
  return `<${node.url}|${linkText}>`;
}

Steps to Reproduce

import { createGoogleChatAdapter } from '@chat-adapter/gchat';

const adapter = createGoogleChatAdapter({ /* … */ });
await adapter.postMessage('gchat:spaces/X:thread', {
  markdown: 'invite sent to hello@example.com',
});

Expected Behavior

The wire-level message GChat receives should be:

invite sent to hello@example.com

(GChat's own renderer auto-links bare email addresses at display time — no <mailto:…|…> wrapping needed when display text == URL tail.)

Actual Behavior

The wire-level message is:

invite sent to <mailto:hello@example.com|hello@example.com>

Same applies for <tel:+15551234|+15551234> when the agent writes a bare phone number that GFM autolinks. The nodeToGChat bare-URL optimization at line 113 should also fire for these schemes.

Suggested Fix

Extend the bare-URL collapse to recognise that for mailto: and tel: scheme URLs, the "bare display" form is the URL with its scheme prefix stripped:

if (isLinkNode(node)) {
  const linkText = getNodeChildren(node)
    .map((child) => this.nodeToGChat(child))
    .join('');
  if (linkText === node.url) return node.url;
  // mailto:/tel: autolinks: GChat renders the bare address as a clickable link.
  // The display-text form is the URL minus the scheme.
  const schemeMatch = node.url.match(/^(mailto|tel):(.+)$/);
  if (schemeMatch && schemeMatch[2] === linkText) return linkText;
  return `<${node.url}|${linkText}>`;
}

Happy to send a PR with the change + a test in markdown.test.ts if the direction looks right.

Chat SDK Version

4.26.0

Node.js Version

23.10

Platform Adapter

Google Chat

Operating System

macOS

Additional Context

Related precedent: #392 (Slack adapter mention regex mangles emails) — same general class of "plain email addresses in agent text need careful handling in adapter rendering."

Currently working around this in our codebase by monkey-patching formatConverter.renderPostable to post-process the rendered output and collapse <mailto:X|X> / <tel:X|X> / <https?://X|X> tokens where the display equals the URL tail. Happy to upstream the equivalent logic via the nodeToGChat change above so the workaround can be removed.