macOS: Support performable: prefix for paste_from_clipboard (parity with GTK PR #10089)

[kyleqihua]

Summary

PR #10089 implemented performable: support for paste_from_clipboard on GTK/Linux, allowing the keybind to pass through when the clipboard contains no text (e.g., only an image). This enables terminal applications like Claude Code to handle image pasting via their own clipboard mechanisms (e.g., wl-paste).

Request: Implement the same functionality for macOS/AppKit.

Use Case

1. User copies an image to clipboard
2. User presses Cmd+V in Ghostty running Claude Code
3. Current behavior (macOS): Ghostty intercepts Cmd+V, finds no text to paste, does nothing. The keypress is consumed and never reaches Claude Code.
4. Expected behavior: With keybind = performable:super+v=paste_from_clipboard, Ghostty should detect that clipboard has no text and pass the keypress through to Claude Code, which can then use pbpaste to read the image.

Context

• This is especially important for users of clipboard managers like Raycast, where selecting an image and pressing Enter sends Cmd+V
• Claude Code and similar AI CLI tools rely on image pasting for context
• The GTK implementation in PR gtk: pass through keypress when clipboard has no text #10089 checks clipboard formats and passes through the keypress when no text is available
• macOS has equivalent APIs (NSPasteboard) to check clipboard content types

Implementation Notes

The GTK implementation:

• Checks if clipboard contains text before pasting
• If no text is available and the performable: prefix is used, the keypress is passed through to the terminal application
• This allows the application to handle the paste itself using platform-specific tools

For macOS, a similar approach could use NSPasteboard.general to check for NSPasteboardTypeString before deciding whether to consume the keypress.

Related

• PR: gtk: pass through keypress when clipboard has no text #10089 (GTK implementation)
• Discussion: Support OSC 52 clipboard read for image data (binary/base64) #10099 (OSC 52 image support - different issue)
• Discussion: Allow copy/paste keybindings to pass through if they did nothing #2811 (performable: keybind discussion)

[rhodes-b]

the original issue claims it already works on macos
#4522

#4591