iPadOS: expose PencilKit/PDFKit to plugins, or add one-tap "open in default app"

Use case or problem

I use Obsidian as my source of truth and want to annotate PDFs with Apple Pencil on iPad without leaving the app. Today the workflow is: leave Obsidian, open Files, navigate to the vault, find the PDF, annotate in Markup, switch back. Annotations write back to the original file in the vault correctly, so the data side works. The problem is the app-switching overhead for what should be one tap.

This is the main reason I still keep GoodNotes installed alongside Obsidian, and the only handwriting workflow I haven’t been able to consolidate.

Proposed solution

Two options, in order of preference.

1. Expose PencilKit and PDFKit to community plugins via a Capacitor bridge.

Specifically, access to PDFKit’s PDFView and PencilKit’s PKCanvasView, so a plugin can render and annotate PDFs inside Obsidian on iPad. This would use the same native frameworks as Markup, Notes, and Books. Palm rejection, predictive touch, pressure and tilt, and the full Pencil tool set come from Apple’s frameworks, not reinvented in JavaScript.

A plugin built on this hook would let users annotate vault PDFs directly in Obsidian without app switching, while keeping notes in the vault.

2. (Smaller scope) Add a one-tap “Open in default app” for vault files on iOS.

A button or command that opens the active vault file in the iPadOS system handler (Markup, Preview, or whatever the user has set), in one tap, without the Files-app detour. Annotations already write back correctly, so this is purely about removing navigation friction.

The same hook helps other use cases beyond PDFs: image editing, audio editing, handing files to specialized apps. It’s a generic capability, not a feature for one plugin.

I’m happy to build the plugin once either hook lands.

Current workaround

Leaving Obsidian, opening Files, navigating to the vault, opening the PDF in Markup, annotating, and switching back. Works, but the friction adds up over a study session.

Related feature requests

(none found yet)

+1 to the “open in default app” path as the pragmatic version of this.

The important detail you called out is that the file round-trip already works once you reach it through Files/Markup. The friction is identity/navigation, not the data model.

From an iOS workflow point of view, a one-tap handoff that opens the current vault file in the system/default handler would solve a lot of this without Obsidian having to own every native Apple framework surface directly.

I’d be curious whether plugin authors can reliably access enough current-file identity on iPadOS to trigger that kind of handoff, or if this needs to be core-app level.

This FR needs to be split in two separate ones.
The first should go in developers and api
and the second… isn’t the “open in default app” already present? It’s called “share” on mobile platforms.