Canonical Technical Definition

A visual admonition container styled with accent borders and icons, authored in Markdown using blockquote syntax paired with an archetype identifier.

Markdown callouts—also known as admonitions, alerts, or info boxes—are visual container blocks designed to emphasize crucial warnings, tips, technical notes, or key takeaways within a document.

Historically, Markdown writers had to resort to raw HTML <div class="alert alert-warning"> tags to create visual callout banners. In 2021, Obsidian popularized an elegant plain-text convention using blockquote syntax paired with bracketed tags (> [!NOTE]). In 2023, GitHub officially adopted this syntax as “GitHub Alerts”, establishing callouts as a de facto Markdown standard.

Standard callout syntax specification

A callout begins with a standard blockquote marker (>), followed by a bracketed identifier with an exclamation mark:

> [!NOTE]
> This is a standard informative note highlighting background context.

> [!TIP]
> Use ⌘D in Oyma to open today's daily note instantaneously.

> [!WARNING]
> Recording meetings without two-party consent may violate local wiretapping laws.

> [!CAUTION]
> Deleting this folder will permanently remove local Markdown notes from disk.

Collapsible callouts (Foldable admonitions)

Extended editors like Obsidian and Oyma support collapsible callouts, allowing writers to tuck away lengthy code listings or technical appendices:

> [!NOTE]+ Expandable Callout (Defaults to Open)
> This content is visible by default, but readers can click the arrow to collapse it.

> [!FAQ]- Collapsed Callout (Defaults to Closed)
> This detail is hidden by default, expanding only when clicked.

Supported archetype styles

Modern editors render callouts with dedicated semantic accent colors and icons:

Callout TypeSemantic PurposeAccent Color Token
[!NOTE]General contextual commentaryAccent Blue
[!TIP]Productivity advice & shortcutsEmerald Green
[!IMPORTANT]Critical prerequisites & requirementsVibrant Purple
[!WARNING]Operational hazards & caveatsAmber Orange
[!CAUTION]Destructive actions & irreversible risksCrimson Red

Callout rendering in Oyma on macOS

In Oyma:

  • Callout syntax renders as refined, native macOS notification cards styled with subtle borders and typography.
  • In live-preview mode, the raw > [!NOTE] marker is concealed while retaining full click-to-edit fidelity.
  • Files remain 100% standard plain text on your Mac’s disk, rendering cleanly on GitHub and inside Obsidian.

Frequently asked questions about Markdown Callout Admonitions

What is the syntax for a Markdown callout?

Begin a blockquote with > and place an archetype tag on the first line inside square brackets: > [!NOTE]. Subsequent lines prefixed with > form the callout body.

How do you create a collapsible callout in Obsidian and Oyma?

Append a plus sign (> [!NOTE]+) for an expandable callout that defaults to open, or a minus sign (> [!NOTE]-) for a collapsible callout that defaults to closed.

What are the official GitHub alert types?

GitHub Flavored Markdown officially supports five alert types: NOTE, TIP, IMPORTANT, WARNING, and CAUTION.