Slack Copy — paste formatted content into Slack messages

Slack's macOS desktop message composer is picky about what it renders from a pasted clipboard. Empirically verified behavior:

Format	Slack message composer?	How to put it on the clipboard
Bold, italic, strikethrough	✅ via HTML	`<b>`, `<i>`, `<s>` on `public.html`
Bulleted / numbered list	✅ via HTML	`<ul><li>`, `<ol><li>`
Inline code	✅ via HTML	`<code>`
Code block	✅ via HTML	`<pre>` (line breaks preserved; `<pre><code>` is equivalent — no syntax highlighting either way)
Blockquote	✅ via HTML	`<blockquote>` (renders with the left bar; `<code>` inside it works)
Links	✅ via HTML	`<a href="…">…</a>`
Table	❌ HTML `<table>` is stripped	Use tab-separated plain text (TSV). Slack renders TSV as a table.
Headings, colors, custom fonts	❌	Not supported in the composer; use a canvas.

Three big gotchas:

slack-copy