Example — Hello Panel

Target design

This example uses the planned manifest and Host API (Writing an Extension Part B), which are not built. A working example of today’s API is Part A of the same page.

A wasm extension contributing one panel and one command; the full walkthrough is in Writing an Extension §2–3. Key points the example demonstrates:

• Manifest-first: the “Hello” panel and “Hello: Greet” command appear in the workbench and palette before the wasm is instantiated.
• State outside the panel: greetings lives in the extension struct; docking the panel elsewhere keeps the count.
• Declarative UI: moonkale_shell::column([...]) is rendered by the host; the same panel works on web (Worker runtime) and desktop (wasmtime).
• Command = LLM tool: adding llm_tool = true to the manifest makes “greet” callable by the in-app agent, gated by policy (risk = "read-only").

Variations to try: give the panel a when = "activePanel == 'editor-code'" so it only shows next to code; store greetings with host.kv_set so it survives restarts.