[hanafusay]

Why

Bots need destination URLs to remain available when a Slack message exceeds the incoming Markdown parse limits. A message containing 2,049 emphasis markers followed by an explicit labeled link currently retains the label but loses the destination from message.formatted.

Summary

Preserve explicit HTTP, HTTPS, mailto, and tel links in the fallback AST using the existing linear control-token scan. Keep message.text, mention rendering, entity decoding, and all parsing limits unchanged. The fallback does not invoke the Markdown parser again.

Add converter and adapter regressions, document the behavior, and include a patch changeset.

Test plan

• Five new regression cases failed before the fix and passed afterward.
• pnpm validate passed, including 1,102 Slack tests, workspace type checks, lint, tests, and builds.
• A built-adapter reproduction retained the URL and label at 2,048 and 2,049 emphasis markers.
• An independent reviewer reran the converter suite and reviewed the fallback paths and input bounds.
• Real Slack API calls and model calls were not exercised.

Checklist

• All commits are signed and verified
• All commits are signed off for the DCO
• pnpm validate passes
• Changeset added
• Documentation updated

[vercel]

@hanafusay is attempting to deploy a commit to the Vercel Team on Vercel.

A member of the Team first needs to authorize it.