What one slot means when you work
Every copy overwrites the last one. No confirmation, no undo, no warning that you are about to lose something. Copy a link, copy a second thing, and the link is gone from the system. ⌘X shares the same slot, so a cut you never pasted disappears the same way.
Any app can read it without asking. The general pasteboard is shared across everything running on your Mac, and reading it needs no permission prompt on macOS.
It does not outlive the session. Restart and the slot is empty, because nothing wrote it down.
Why nobody revisited it for decades
The pasteboard API has room for several named pasteboards, and macOS uses them for dragging and for find operations. None of them was ever a history. Apple's position for years was that an app could implement its own, and plenty did.
So the fix, when it arrived, came as a separate feature rather than a change to the clipboard. Tahoe records copies for Spotlight to show you. ⌘C and ⌘V behave exactly as before.
An app-level history is a different object from the pasteboard. It writes each copy to a local database and keeps the type, so an image stays image data and a colour stays a colour rather than becoming a string.
That distinction is why a screenshot copied last week can still be pasted as a screenshot. Storing screenshots properly is much harder than it looks, because a file path breaks the moment the file moves.
What macOS 26 actually added
Press ⌘Space then ⌘4 and Spotlight shows your recent copies. It keeps 8 hours by default, and the Clipboard switch in System Settings, then Spotlight, offers 30 minutes, 8 hours or 7 days. An empty ⌘4 panel right after you copied something usually means the switch is off.
Two limits matter. It is plain text only, with no images and no text recognition inside them. And it needs macOS 26, so every Mac on Sonoma or Sequoia gets nothing at all. The history does survive a reboot, which the clipboard itself does not.
What I do about it
The single slot is the reason Klipto exists. I copy and paste a couple of hundred times a day, and losing a link to the next ⌘C stopped being acceptable. Klipto records every copy to a local database, and holding ⌥⌘V walks back through it. Releasing the keys pastes the item you landed on.
For free clipboard history on macOS 14 or later, Maccy is a fine answer. Open source, MIT, about 1.6 MB, 200 items by default and up to 999.