“Local-first” is useful shorthand, but it can hide several separate questions. A note can be available offline while still living in an app-managed database. A folder of local files can still be synced to a cloud service. An app can support export without exposing its internal store as files.
Start with local access
Can you open and edit a note without a network connection? Can you search or browse the notes already on the device? What happens to an edit when the connection returns? A calm offline experience is often more valuable than a slogan about ownership.
Then ask about the data model
Some workflows keep one .md file per note. Others keep structured records in a local database and mirror them to a cloud service. Both can provide fast local access. The difference matters for direct file access, backups, and moving to another tool.
If files matter to you, inspect them. If the app uses its own store, test bulk export and restoration. The Markdown files guide explains what a file-based collection looks like.
Sync is a convenience; backup is recovery
Sync attempts to keep devices current. It may also propagate an accidental deletion. Keep a separate recovery path: a versioned backup, an export, or another method appropriate to the value of the notes. Verify it by opening a restored sample.
Privacy is another question. Read what an app sends, what is stored under your account, and whether private content is used for analytics or other processing. The term “local-first” alone does not settle those details.
The best practical question is: If this app disappeared tomorrow, what exactly could I still open? A good workflow gives you a concrete answer. See exporting Markdown and iCloud models for the next checks.