Continue numbered Markdown lists in the composer

[jackelly7]

Area

apps/web, including the desktop app that wraps the web client

Problem or use case

The message composer accepts Markdown as plain text, but starting a numbered list means typing every marker by hand. After writing 1. First item, inserting a newline leaves an empty line instead of continuing with 2. .

This is a small but frequent interruption when a prompt contains a sequence of requirements or review notes.

Proposed solution

Continue decimal Markdown list markers when the user inserts a newline:

• 1. First item becomes 1. First item\n2. .
• Preserve leading indentation for nested or indented lists.
• Increment any decimal marker rather than requiring the list to start at 1.
• If the current item contains only its marker, inserting another newline removes that marker and exits the list.
• Do not renumber existing text or turn the composer into a rich-text editor.

On desktop this applies to Shift+Enter, since plain Enter sends the message. It also applies wherever the web composer already treats Enter as a newline. Native mobile has a separate composer and is outside the smallest first pass.

Why this matters

Numbered requirements are common in coding prompts. Continuing the marker matches the behavior of familiar Markdown editors while keeping the stored prompt as ordinary Markdown text.

Smallest useful scope

Support decimal markers in the shared web/desktop composer. Add focused tests for incrementing, preserving indentation, exiting an empty item, and leaving ordinary lines unchanged.

Alternatives considered

A full rich-text or Markdown-shortcut plugin would add far more behavior and state than this interaction needs. Supporting bullets, checkboxes, alternate ordered-list delimiters, and automatic renumbering can remain separate ideas.

Risks or tradeoffs

A line beginning with a number and period may not be intended as a list. Requiring whitespace after the period and triggering only when the user explicitly inserts a newline keeps accidental activation narrow. The empty-item behavior gives the user an immediate way out.

Contribution

• I would be open to helping implement this as a focused change.

[juliusmarminge]

Resolved by #12160 — Enter now continues numbered/bullet/task Markdown list markers in the composer (and exits on an empty item), in both plain and rich modes.