Show HN: Paste-preview – see and mark up images you paste into Claude Code

Developer alan890104 released paste-preview, a Claude Code plugin that renders pasted images as labelled thumbnails and opens an annotation editor with pen, ellipse, box, arrow, text, crop, rotate and seven colours before the prompt is sent. The plugin installs via `/plugin install paste-preview --marketplace alan890104/claude-code-paste-preview` and requires Claude Code 2.1.291 or newer, with thumbnails needing a kitty-graphics-protocol terminal such as Ghostty or kitty. On macOS the editor runs as a native floating panel compiled once via Xcode Command Line Tools and idles at about 100 MB, quitting after 20 minutes unused; Linux and Windows require Node.js 18 or newer.

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. paste-preview-en.mp4 A Claude Code https://claude.com/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. - 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 https://ghostty.org or kitty https://sw.kovidgoyal.net/kitty/ . Other terminals Windows Terminal among them show Image N in place of the picture, with its Edit button. | | The editor | The clipboard, only when Claude Code's own copy of a paste can't be found | |---|---|---| | macOS | The Xcode Command Line Tools xcode-select --install . The panel is compiled once, on first use, in a few seconds. Without them the editor opens as a Google Chrome app window instead, which needs Node.js and Chrome. | Optional: pngpaste https://github.com/jcsalterego/pngpaste brew install pngpaste | | Linux | Node.js 18 or newer node on PATH . The editor opens as an app window of Chrome, Chromium, Edge or Brave when one is installed, else in the default browser xdg-open . | wl-clipboard Wayland or xclip X11 , the tools Claude Code itself pastes images with | | Windows | Node.js 18 or newer node.exe on PATH . The editor opens as a Microsoft Edge app window Chrome where Edge is missing , else in the default browser. | Nothing: PowerShell, built in | Where something is missing the mod says so in a toast: which tool, and the thumbnail still shows. 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. | Key | | |---|---| | P O B A T | pen, ellipse, box, arrow, text | | C | crop: drag a frame, then Enter | | R | rotate 90° | | 1 – 7 | colour | | ⌘Z Ctrl+Z on Linux and Windows | undo | | Shift while drawing | a circle or square | | Enter | done | | Esc | cancel and keep the picture as pasted | 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. - 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. - 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. - The editor's text tool uses the system input method. If typing Chinese or Japanese into the floating panel misbehaves, please open an issue. 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. | Path | | |---|---| | hooks/register.tsx | the mod: finding pastes, thumbnails, the editor queue, what happens at Enter | | hooks/platform.ts | what differs on macOS, Linux and Windows: folders, clipboard commands, the editor's command | | editor/editor.html | the editor canvas | | editor/panel.swift | the floating panel that hosts the editor | | editor/server.mjs | the editor in a browser window: on Linux and Windows, and on a Mac without Swift |