Claude Code mods in the desktop app: a one-page summary and what to recheck after updates

This series covered the minimum steps for using Claude Code mods in the desktop app's Code tab, and answers to the problems people search for most. Here is the whole thing on one page.

Everything on one page

Question	Answer	Part
What are mods?	JS/TS functions that run inside Claude Code. They draw panes and bands and can intercept tool calls	1
Where do they render?	Only in the terminal and the desktop Code tab. Desktop from 2.1.286	1
How to build one	Three files: plugin.json, hooks.json, register.tsx. Branch on e.surface per surface	2
Panes	Open with $.ui.open({ id }), draw in the ui.render Pane while checking e.requestId	3
Bands, status line, toasts	AbovePrompt, $.ui.status, $.ui.toast	4
Nothing renders	Static check, runtime environment, component rules. Search the debug log for the mod's name	5
Broken on desktop	Auto-open from 144 columns, colors by theme name, Svg needs width and height, don't set isInteractive	6
Doesn't work on Windows	$.process launches programs Windows doesn't have. Replace with the API. Sound via SoundPlayer	7
Asking from a button does nothing	The press only queues; the clock sends	8
Distributing and installing	Add marketplace.json and push. /plugin install name@marketplace-name	9
Is it safe?	No sandbox. Read validate output and the four APIs, pin with sha	10

When the version goes up

Mods are a brand-new feature, and each version adds events, APIs and components. The behavior in this series was checked on 2.1.286 to 2.1.288. When the version goes up, recheck in this order:

1. Run /status in the desktop app to see the bundled Claude Code version
2. Read the type definitions written out when loading with --plugin-dir (.claude-plugin/types/). They're more accurate than the web pages
3. The workarounds (Windows sound, sending $.prompt.submit from a clock) become unnecessary once the core fixes them. Try the straightforward way first

See real mods

To see real mods, the modscode reviewed gallery lists mods written for the desktop app that run on Windows and passed the review, each with a UI preview and code. To search them from inside a conversation with Claude, connect the modscode MCP connector.

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This article was written with AI assistance (Claude) and checked against the official Claude Code docs; anything marked "not verified" could not be confirmed there.