claude-code-paste-preview

Install

At the prompt of a Claude Code session in a terminal:

/plugin install paste-preview --marketplace alan890104/claude-code-paste-preview

Answer y to add the marketplace, then pick a scope (user scope loads it in every session). It runs at once, with no restart.

https://github.com/user-attachments/assets/7098c51e-ce1e-43ad-9fe3-5189ef1fdb88

A Claude Code mod for the images you paste. In the terminal a pasted image is just [Image #1], and three pastes later you can't tell which is which. With this mod:

• You see what you pasted. Every [Image #N] in the prompt box shows as a thumbnail above the prompt, and sent prompts show theirs in the transcript, each labelled Image #N.
• You can mark it up before sending. An editor opens the moment you paste: pen, ellipse, box, arrow, text, crop, rotate, seven colours, undo. Press Enter when done, or Esc to keep the picture as pasted.
• Claude gets the marked-up version. At Enter the original paste is left out of the message and Claude is pointed at the edited picture.
• Full screen works on macOS. There the editor is a native floating panel that sits over a full-screen terminal the way Spotlight does: no Space switch, and the keys return to the prompt when it closes. It waits ready in the background, so it appears the instant you paste (about 100 MB while it waits; after 20 minutes unused it quits, and comes back as you type). On Linux and Windows it opens as a browser app window.

Requirements

• macOS, Linux or Windows
• Claude Code 2.1.291 or newer (mods are an early-access feature)
• For thumbnails, a terminal with the kitty graphics protocol, such as Ghostty or kitty. Other terminals (Windows Terminal among them) show Image #N in place of the picture, with its Edit button.

Where something is missing the mod says so in a toast: which tool, and the thumbnail still shows.

Use

Paste an image as usual: Ctrl+V, or Alt+V on Windows and under WSL, the keys Claude Code itself binds to pasting an image (chat:imagePaste). The editor opens on its own.

To edit a picture again, press Edit under its thumbnail above the prompt (or ctrl+x tab, then its number).

The editor and the thumbnail labels follow the system's language (macOS's first preferred language; on Linux LC_ALL, else LC_MESSAGES, else LANG; on Windows the UI culture) in five languages: English, Traditional Chinese (zh-Hant, and zh-TW, zh-HK, zh-MO), Simplified Chinese (zh-Hans, and any other zh: zh-CN, zh-SG, bare zh), Japanese (ja) and Korean (ko). Any other language gets English. This README is available in the same five languages, linked at the top.

In a plain browser tab (the default browser on Linux or Windows, where no Chromium browser is installed), the page can't close itself: after Done or Cancel it says the tab can be closed.

How it works

• Claude Code writes each paste to <tmp>/claude-<uid>/<project>/<session>/images/<N>.png (<tmp> is /tmp on macOS and $TMPDIR or /tmp on Linux), or %TEMP%\claude\<project>\<session>\images\<N>.png on Windows; CLAUDE_CODE_TMPDIR moves it on all three. The mod reads that copy, so the thumbnail and the editor show exactly what was pasted. That folder is Claude Code's internal layout, not an API; if it moves, the mod falls back to reading the clipboard.
• Edited pictures are written to /private/tmp/paste-preview/<session>/<N>.png on macOS, /tmp/paste-preview-<uid>/<session>/<N>.png on Linux (a folder only you can read) and %TEMP%\paste-preview\<session>\<N>.png on Windows. Folders older than a week are removed.
• On Linux and Windows no tool for making thumbnails comes with every system, so the band reads the picture's size from its header and the terminal scales the picture itself; an edit comes back from the editor with a 480 px copy for the band.
• A plugin cannot change or add an image in a message, only drop one. So at Enter the mod drops the original paste's image block (session.append) and adds a note for Claude beside the prompt (prompt.submit context) naming the edited file, which Claude then reads. You'll see that read in the transcript. The prompt box and the transcript keep showing [Image #N].
• To find the right block, the mod checks the image's place in the message and its aspect ratio. If neither matches, it drops nothing: Claude then gets both the original and the edit, never the wrong one.

Limits

• On Linux and Windows the editor is a browser window, not a panel: over a full-screen terminal it may switch to another desktop, and the keys go back to the terminal only when the window closes (or when you click it).
• Under WSL the mod runs as on Linux; the editor opens in a Linux browser when one is installed, else through wslview or Windows' explorer.exe.
• Thumbnails in the transcript cover the current session. After a restart, older messages show [Image #N] as before.
• Inside tmux or GNU screen there are no thumbnails: Claude Code draws no pictures there, so above the prompt and in the transcript each paste shows as Image #N with its Edit button, as in other terminals. The editor works as usual. For thumbnails, run Claude Code straight in Ghostty or kitty, outside tmux.
• The editor's text tool uses the system input method. If typing Chinese or Japanese into the floating panel misbehaves, please open an issue.

Development

git clone https://github.com/alan890104/claude-code-paste-preview
cd claude-code-paste-preview
claude --plugin-dir .            # run Claude Code with the mod loaded from this folder
claude plugin validate .         # what the engine will load and refuse
claude plugin test .             # hooks/*.test.tsx: the band, the send, and a paste on each system
node test/e2e.mjs [--clipboard]  # the mod's own commands for real on this machine (Node 22.6+)
node test/live.mjs               # Linux, Windows: a live session pasted into, offline

test/e2e.mjs puts a picture on the clipboard and reads it back with the commands the mod runs, starts the editor server as the mod does, draws on the page with a headless browser and checks the edited picture lands where the mod reads it. It needs playwright-core (PLAYWRIGHT_DIR names a folder whose node_modules holds it) and Chrome. test/live.mjs starts Claude Code itself with the mod in a pseudo-terminal (@lydell/node-pty, in the same folder), pastes with Claude Code's own key, draws in the editor the mod opens, presses Enter and reads the transcript; its key is made up and the API's address is a closed local port, so nothing is sent. CI (.github/workflows/test.yml) runs them with the plugin tests on macOS, Linux and Windows (the live session on Linux and Windows).

Loading the folder once writes the engine's type declarations to .claude-plugin/types/; after that, tsc -p . type-checks the mod.

License

MIT