# Changelog

> True HMR for Lit components, CSS delivery helpers, and a DevTools timeline for Vite.

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## Version 0.3.0

Sep 17, 2026

The DevTools half of the plugin was rebuilt on [devframe](https://www.npmjs.com/package/devframe), and most of what follows falls out of that: the panel is no longer tied to Vite DevTools, and the same data it shows is reachable by a coding agent over MCP.

### Added

* **The panel runs on devframe.** The bespoke transport is gone. The panel works docked in Vite DevTools, in its own tab, or standalone from the CLI.
* **`lit-devtools` CLI.** `lit-devtools dev` serves the panel without a Vite dev server of its own; `lit-devtools mcp` exposes the panel’s data to an MCP client over stdio, discovering a running dev server on its own.
* **MCP tools for agents** — list the component tree, read recent timeline events, start and stop a recording, and read why a module fell back to a full reload instead of a hot patch.
* **Updates tab.** The timeline reads as an explainer for a single update: what changed, which components re-rendered, and what it cost.
* **Session export.** A recorded session can be written out as a static copy of the panel — shareable, no dev server needed to open it.
* **Deep links.** Panel views are addressable, so a link opens the tab, the selected element, or an exported snapshot at the right place.
* **Flash on update.** An opt-in fading outline over every element that finishes an update, with an optional ramp colouring it by updates per second.
* **Ambient types for `virtual:lit-plugin/timeline`**, shipped in `@oddsquad/vite-plugin-lit/client` alongside the CSS query declarations. Following the custom-layers guide no longer means silencing `TS2307`.
* **Documentation site** at <https://oddcelot.github.io/vite-plugin-lit/>, and a CI workflow that type checks, lints, tests and builds every push.

### Changed

* Panel settings persist per developer through devframe’s settings store instead of per browser, so they follow you across browsers and survive clearing site data. `localStorage` stays as the page’s boot-time cache.
* Source links open through the shared open-in-editor service and resolve against the Vite root.
* The docked panel draws its hover outline over a direct page channel rather than routing through the dev server.
* Tooling moved to Vite+ (oxfmt, oxlint, tsgolint); dependencies updated to TypeScript 7, Vite 8.3, es-module-lexer 3 and magic-string 1.
* The README is a front door now; the long-form guides live on the docs site.

### Fixed

* **`virtual:lit-plugin/timeline` broke `vite build`.** Both hooks lived on the serve-only plugin, so nothing claimed the specifier during a build and the bundler failed on a module the developer never wrote. It now resolves in dev and build alike, stubbing itself out in any build.
* The dev-server endpoints reject cross-site requests.
* Source metadata is injected in the component class’s own scope, so it can no longer reference a class that isn’t in scope.
* The DevTools element watch survives a hot patch; `updated()` is resolved lazily rather than captured once.
* Recording state is synced to a page runtime when it connects, so a reload mid-recording keeps recording.
* `recent-events` works when called with no arguments, and the documented MCP endpoint path matches the one the server serves.