Message flow

How keys become actions across processes

High level

Key event (content)
  → key_handler / mode state
  → port message to service worker
  → command resolution (maps, counts)
  → Chrome API or response to content / UI

Omnibar and Options pages use extension messaging similarly, with ports for streaming completion results.

Ports

Long-lived connections carry:

• Frame registration
• Completion queries / results
• Status and HUD updates
• Injector / protocol handshakes

Port names and mark keys use VimiumPlus protocol tokens (not legacy third-party names). See Protocol tokens.

Command execution

1. User chord completes or palette fires a short name
2. Background resolves to a typed command
3. Handlers in tab_commands, frame_commands, tools, quick_actions, etc. run
4. Failures surface via HUD or UI toast when possible

Restricted pages

When content scripts are absent, the side panel and global commands still reach the service worker with a user gesture.

Debugging

1. Content DevTools → console on the page
2. Service worker DevTools from chrome://extensions
3. Options / sidepanel page DevTools for UI bugs