Preferred extension architecture

ISA Warden itself is primarily built with:

• Svelte and Vite in chat-ui-3/package.json
• Rust and Tauri in chat-ui-3/src-tauri/Cargo.toml

The preferred extension architecture is therefore:

• UI: Svelte-based web UI
• Native/backend logic: Rust native binary when native logic is needed
• Host integration: browser bridge via window.isaExtensionBridge

2.1 Default implementation guidance

Use the following default decision order:

1. Use a browser-only extension if the host already provides the needed capabilities.
2. Add Rust native logic only when the extension needs long-running work, local services, parsing, local binaries, or OS-facing behavior.
3. Use host APIs before building a parallel service layer.

2.2 Allowed alternatives

Alternative stacks are allowed, but they are not preferred.

If an extension diverges from the preferred stack, it must still:

• package correctly
• integrate with the host bridge
• comply with rights and permission rules
• comply with styling rules in this specification
• clearly document build and runtime tradeoffs