diff --git a/.changeset/semi-framework-deps-stay-out-of-optimize.md b/.changeset/semi-framework-deps-stay-out-of-optimize.md
new file mode 100644
index 0000000..0592eb1
--- /dev/null
+++ b/.changeset/semi-framework-deps-stay-out-of-optimize.md
@@ -0,0 +1,5 @@
+---
+'@solidjs/vite-plugin': patch
+---
+
+Fix `vite dev` failing in dependency optimization for apps using a Solid library that ships build-time code in the same package (#375). Since the semi-framework classification landed (any package with `solid-js` / `@solidjs/web` in `dependencies` or `peerDependencies` is `ssr.noExternal` so it shares the app's runtime copy), vitefu's crawl also deep-included every CJS dependency of such a package into the browser's `optimizeDeps.include`, exactly as it does for framework packages. For `@yak/solid` that is `@swc/core`, and rolldown failed on its native `.node` binding (`UNLOADABLE_DEPENDENCY … stream did not contain valid UTF-8`) before the dev server served a page. Sharing the runtime needs nothing pre-bundled, so include chains that pass through a semi-framework package are dropped; a browser-side CJS dependency of one is discovered and optimized on first use, as before the package was classified. Framework packages (a `solid` export condition) keep vitefu's full treatment.
diff --git a/src/index.ts b/src/index.ts
index bc111bf..ef599d3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1084,6 +1084,9 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
   // `buildInputs`, which lists every route module). Null outside start mode.
   let startClientEntryId: string | null = null;
   let solidPkgsConfig: Awaited<ReturnType<typeof crawlFrameworkPkgs>>;
+  // Names of the packages `isSemiFrameworkPkgByJson` classified, so their
+  // dependencies can be taken back out of `optimizeDeps.include` (see below).
+  const semiFrameworkPkgs = new Set<string>();
   const tsrxCss = new Map<string, string>();
 
   // The client build's manifest, read back by SSR builds. In builder-mode
@@ -1274,12 +1277,35 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
           // would split it just the same), never vitest (it manages inlining
           // via test.server.deps).
           if (!(replaceDev || observe) || isTestMode) return false;
-          return SOLID_RUNTIME_PKGS.some(
+          const semi = SOLID_RUNTIME_PKGS.some(
             (name) => pkgJson.dependencies?.[name] || pkgJson.peerDependencies?.[name],
           );
+          if (semi && typeof pkgJson.name === 'string') semiFrameworkPkgs.add(pkgJson.name);
+          return semi;
         },
       });
 
+      // A semi-framework package is inlined for ONE reason: so it resolves the
+      // runtime through Vite and shares the app's copy. vitefu's crawl treats
+      // it like a framework package for its dependencies too — every CJS
+      // dependency is deep-included (`"pkg > dep"`) so the browser optimizer
+      // pre-bundles it. For a library that ships its build-time half in the
+      // same package (a Vite plugin, a compiler binding, a CLI) that pushes
+      // node-only modules into the client's pre-bundle: `@yak/solid` lists
+      // `@swc/core`, and rolldown then fails on its native `.node` binding
+      // before `vite dev` serves a page (#375). Nothing about sharing the
+      // runtime needs the package's dependencies pre-bundled, so any chain
+      // that runs through a semi-framework package is dropped; a browser-side
+      // CJS dependency of such a package is discovered and optimized on
+      // first use instead, as it was before the package was classified at
+      // all. Framework packages (a `solid` export condition) keep vitefu's
+      // full treatment — that is the long-standing contract for them.
+      if (semiFrameworkPkgs.size > 0) {
+        solidPkgsConfig.optimizeDeps.include = solidPkgsConfig.optimizeDeps.include.filter(
+          (entry) => !entry.split(' > ').some((name) => semiFrameworkPkgs.has(name)),
+        );
+      }
+
       // fix for bundling dev in production
       const nestedDeps = replaceDev ? ['solid-js', '@solidjs/web'] : [];