Markdown fieldtype asset picker inserts `statamic://undefined` (regression from #14366)

[joshuap]

Bug description

Selecting an asset via the Markdown fieldtype's asset picker inserts a markdown link/image with an undefined reference:

![alt text](statamic://undefined)

Bard is not affected afaik — it uses a different code path.

How to reproduce

1. On a fresh Statamic 6.7.2+ app, create an entry with a Markdown field that has an asset container configured.
2. In the editor, click the asset picker icon and select any asset.
3. Observe that the inserted markdown is ![alt](statamic://undefined) instead of ![alt](statamic://asset::container/path/to/file.ext).

Logs

No relevant logs

Environment

Laravel Version: 12.59.0
PHP Version: 8.3.31
Composer Version: 2.9.5
Environment: local
Debug Mode: ENABLED
Maintenance Mode: OFF
Timezone: UTC
Locale: en

Cache
Config: NOT CACHED
Events: NOT CACHED
Routes: NOT CACHED
Views: CACHED

Drivers
Broadcasting: log
Cache: file
Database: sqlite
Logs: stack / single
Mail: log
Queue: sync
Session: file

Storage
public/storage: NOT LINKED

Statamic
Addons: 3
License Key: Set
Sites: 1
Stache Watcher: Enabled
Static Caching: Disabled
Version: 6.19.0 PRO

Statamic Addons
doefom/statamic-export: 0.7.0
honeybadger/revision-diff: dev-joshuap/post-diff
statamic/seo-pro: 7.9.0

Installation

Fresh statamic/statamic site via CLI

Additional details

Here's the root cause according to Claude:

PR #14366 (Statamic 6.7.2, merged 2026-03-27) replaced the resource returned by POST /cp/assets-fieldtype from Statamic\Http\Resources\CP\Assets\Asset with the slimmer
Statamic\Http\Resources\CP\Assets\AssetsFieldtypeAsset. The new resource omits the reference key:

https://github.com/statamic/cms/blob/6.x/src/Http/Resources/CP/Assets/AssetsFieldtypeAsset.php

But the Markdown fieldtype still reads asset.reference when an asset is selected:

https://github.com/statamic/cms/blob/6.x/resources/js/components/fieldtypes/markdown/MarkdownFieldtype.vue#L585

const url = encodeURI(`statamic://${asset.reference}`);

asset.reference is undefined, so the inserted URL is the literal string statamic://undefined.