fix(studio): make local source launches reliable

packages/cli/src/__tests__/studio-runtime.test.ts

@@ -12,6 +12,32 @@ describe("studio runtime resolution", () => {
     vi.resetModules();
   });
 
+  it("prefers the repository-local tsx loader for monorepo sources", async () => {
+    accessMock.mockImplementation(async (path: string) => {
+      if (
+        path === "/repo/packages/studio/src/api/index.ts" ||
+        path === "/repo/packages/studio/node_modules/tsx/dist/loader.mjs"
+      ) {
+        return;
+      }
+      throw new Error(`missing: ${path}`);
+    });
+
+    const { resolveStudioLaunch } = await import("../commands/studio.js");
+    const launch = await resolveStudioLaunch("/repo/test-project");
+
+    expect(launch).toEqual({
+      studioEntry: "/repo/packages/studio/src/api/index.ts",
+      command: "node",
+      args: [
+        "--import",
+        "/repo/packages/studio/node_modules/tsx/dist/loader.mjs",
+        "/repo/packages/studio/src/api/index.ts",
+        "/repo/test-project",
+      ],
+    });
+  });
+
   it("finds monorepo packages/studio sources from a project directory", async () => {
     accessMock.mockImplementation(async (path: string) => {
       if (path === "/repo/packages/studio/src/api/index.ts") {

packages/cli/src/commands/studio.ts

@@ -1,12 +1,12 @@
 import { Command } from "commander";
 import { findProjectRoot, log, logError } from "../utils.js";
 import { spawn } from "node:child_process";
-import { join } from "node:path";
+import { dirname, join } from "node:path";
 import { access } from "node:fs/promises";
 
 export interface StudioLaunchSpec {
   readonly studioEntry: string;
-  readonly command: "npx" | "node";
+  readonly command: string;
   readonly args: string[];
 }
 
@@ -29,6 +29,28 @@ export async function resolveStudioLaunch(root: string): Promise<StudioLaunchSpe
     join(root, "..", "studio", "src", "api", "index.ts"),
   ]);
   if (sourceEntry) {
+    const studioPackageRoot = dirname(dirname(dirname(sourceEntry)));
+    const localTsxLoader = await firstAccessiblePath([
+      join(studioPackageRoot, "node_modules", "tsx", "dist", "loader.mjs"),
+    ]);
+    if (localTsxLoader) {
+      return {
+        studioEntry: sourceEntry,
+        command: "node",
+        args: ["--import", localTsxLoader, sourceEntry, root],
+      };
+    }
+
+    const localTsx = await firstAccessiblePath([
+      join(studioPackageRoot, "node_modules", ".bin", "tsx"),
+    ]);
+    if (localTsx) {
+      return {
+        studioEntry: sourceEntry,
+        command: localTsx,
+        args: [sourceEntry, root],
+      };
+    }
     return {
       studioEntry: sourceEntry,
       command: "npx",

packages/studio/package.json

@@ -35,6 +35,7 @@
     "@vitejs/plugin-react": "^4.4.0",
     "autoprefixer": "^10.4.0",
     "tailwindcss": "^4.0.0",
+    "tsx": "^4.20.6",
     "typescript": "^5.8.0",
     "vite": "^6.0.0",
     "vitest": "^3.0.0"

pnpm-lock.yaml

@@ -34,7 +34,7 @@ importers:
         version: 5.9.3
       vitest:
         specifier: ^3.0.0
-        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))
+        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(tsx@4.21.0)
 
   packages/core:
     dependencies:
@@ -62,7 +62,7 @@ importers:
         version: 5.9.3
       vitest:
         specifier: ^3.0.0
-        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))
+        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(tsx@4.21.0)
 
   packages/studio:
     dependencies:
@@ -111,7 +111,7 @@ importers:
     devDependencies:
       '@tailwindcss/vite':
         specifier: ^4.0.0
-        version: 4.2.1(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))
+        version: 4.2.1(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))
       '@types/node':
         specifier: ^22.0.0
         version: 22.19.15
@@ -123,22 +123,25 @@ importers:
         version: 19.2.3(@types/react@19.2.14)
       '@vitejs/plugin-react':
         specifier: ^4.4.0
-        version: 4.7.0(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))
+        version: 4.7.0(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))
       autoprefixer:
         specifier: ^10.4.0
         version: 10.4.27(postcss@8.5.8)
       tailwindcss:
         specifier: ^4.0.0
         version: 4.2.1
+      tsx:
+        specifier: ^4.20.6
+        version: 4.21.0
       typescript:
         specifier: ^5.8.0
         version: 5.9.3
       vite:
         specifier: ^6.0.0
-        version: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+        version: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
       vitest:
         specifier: ^3.0.0
-        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))
+        version: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(tsx@4.21.0)
 
 packages:
 
@@ -1668,6 +1671,9 @@ packages:
     resolution: {integrity: sha512-kVCxPF3vQM/N0B1PmoqVUqgHP+EeVjmZSQn+1oCRPxd2P21P2F19lIgbR3HBosbB1PUhOAoctJnfEn2GbN2eZA==}
     engines: {node: '>=18'}
 
+  get-tsconfig@4.13.7:
+    resolution: {integrity: sha512-7tN6rFgBlMgpBML5j8typ92BKFi2sFQvIdpAqLA2beia5avZDrMs0FLZiM5etShWq5irVyGcGMEA1jcDaK7A/Q==}
+
   glob-parent@5.1.2:
     resolution: {integrity: sha512-AOIgSQCepiJYwP3ARnGx+5VnTu2HBYdzbGP45eLw1vr3zB3vZLeyed1sC9hnbcOc9/SrMyM5RPQrkGz4aS9Zow==}
     engines: {node: '>= 6'}
@@ -2318,6 +2324,9 @@ packages:
     resolution: {integrity: sha512-pb/MYmXstAkysRFx8piNI1tGFNQIFA3vkE3Gq4EuA1dF6gHp/+vgZqsCGJapvy8N3Q+4o7FwvquPJcnZ7RYy4g==}
     engines: {node: '>=4'}
 
+  resolve-pkg-maps@1.0.0:
+    resolution: {integrity: sha512-seS2Tj26TBVOC2NIc2rOe2y2ZO7efxITtLZcGSOnHHNOQ7CkiUBfw0Iw2ck6xkIhPwLhKNLS8BO+hEpngQlqzw==}
+
   restore-cursor@5.1.0:
     resolution: {integrity: sha512-oMA2dcrw6u0YfxJQXm342bFKX/E4sG9rbTzO9ptUcR/e8A33cHuvStiYOwH7fszkZlZ1z/ta9AAoPk2F4qIOHA==}
     engines: {node: '>=18'}
@@ -2557,6 +2566,11 @@ packages:
   tslib@2.8.1:
     resolution: {integrity: sha512-oJFu94HQb+KVduSUQL7wnpmqnfmLsOA/nAh6b6EH0wCEoK0/mPeXU6c3wKDV83MkOuHPRHtSXKKU99IBazS/2w==}
 
+  tsx@4.21.0:
+    resolution: {integrity: sha512-5C1sg4USs1lfG0GFb2RLXsdpXqBSEhAaA/0kPL01wxzpMqLILNxIxIOKiILz+cdg/pLnOUxFYOR5yhHU666wbw==}
+    engines: {node: '>=18.0.0'}
+    hasBin: true
+
   tw-animate-css@1.4.0:
     resolution: {integrity: sha512-7bziOlRqH0hJx80h/3mbicLW7o8qLsH5+RaLR2t+OHM3D0JlWGODQKQ4cxbK7WlvmUxpcj6Kgu6EKqjrGFe3QQ==}
 
@@ -3484,12 +3498,12 @@ snapshots:
       '@tailwindcss/oxide-win32-arm64-msvc': 4.2.1
       '@tailwindcss/oxide-win32-x64-msvc': 4.2.1
 
-  '@tailwindcss/vite@4.2.1(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))':
+  '@tailwindcss/vite@4.2.1(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))':
     dependencies:
       '@tailwindcss/node': 4.2.1
       '@tailwindcss/oxide': 4.2.1
       tailwindcss: 4.2.1
-      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
 
   '@ts-morph/common@0.27.0':
     dependencies:
@@ -3554,7 +3568,7 @@ snapshots:
 
   '@types/validate-npm-package-name@4.0.2': {}
 
-  '@vitejs/plugin-react@4.7.0(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))':
+  '@vitejs/plugin-react@4.7.0(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))':
     dependencies:
       '@babel/core': 7.29.0
       '@babel/plugin-transform-react-jsx-self': 7.27.1(@babel/core@7.29.0)
@@ -3562,7 +3576,7 @@ snapshots:
       '@rolldown/pluginutils': 1.0.0-beta.27
       '@types/babel__core': 7.20.5
       react-refresh: 0.17.0
-      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
     transitivePeerDependencies:
       - supports-color
 
@@ -3574,14 +3588,14 @@ snapshots:
       chai: 5.3.3
       tinyrainbow: 2.0.0
 
-  '@vitest/mocker@3.2.4(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))':
+  '@vitest/mocker@3.2.4(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))':
     dependencies:
       '@vitest/spy': 3.2.4
       estree-walker: 3.0.3
       magic-string: 0.30.21
     optionalDependencies:
       msw: 2.12.13(@types/node@22.19.15)(typescript@5.9.3)
-      vite: 7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+      vite: 7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
 
   '@vitest/pretty-format@3.2.4':
     dependencies:
@@ -4224,6 +4238,10 @@ snapshots:
       '@sec-ant/readable-stream': 0.4.1
       is-stream: 4.0.1
 
+  get-tsconfig@4.13.7:
+    dependencies:
+      resolve-pkg-maps: 1.0.0
+
   glob-parent@5.1.2:
     dependencies:
       is-glob: 4.0.3
@@ -4767,6 +4785,8 @@ snapshots:
 
   resolve-from@4.0.0: {}
 
+  resolve-pkg-maps@1.0.0: {}
+
   restore-cursor@5.1.0:
     dependencies:
       onetime: 7.0.0
@@ -5061,6 +5081,13 @@ snapshots:
 
   tslib@2.8.1: {}
 
+  tsx@4.21.0:
+    dependencies:
+      esbuild: 0.27.3
+      get-tsconfig: 4.13.7
+    optionalDependencies:
+      fsevents: 2.3.3
+
   tw-animate-css@1.4.0: {}
 
   type-fest@5.4.4:
@@ -5105,13 +5132,13 @@ snapshots:
 
   vary@1.1.2: {}
 
-  vite-node@3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1):
+  vite-node@3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0):
     dependencies:
       cac: 6.7.14
       debug: 4.4.3
       es-module-lexer: 1.7.0
       pathe: 2.0.3
-      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+      vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
     transitivePeerDependencies:
       - '@types/node'
       - jiti
@@ -5126,7 +5153,7 @@ snapshots:
       - tsx
       - yaml
 
-  vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1):
+  vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0):
     dependencies:
       esbuild: 0.25.12
       fdir: 6.5.0(picomatch@4.0.3)
@@ -5139,8 +5166,9 @@ snapshots:
       fsevents: 2.3.3
       jiti: 2.6.1
       lightningcss: 1.31.1
+      tsx: 4.21.0
 
-  vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1):
+  vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0):
     dependencies:
       esbuild: 0.27.3
       fdir: 6.5.0(picomatch@4.0.3)
@@ -5153,12 +5181,13 @@ snapshots:
       fsevents: 2.3.3
       jiti: 2.6.1
       lightningcss: 1.31.1
+      tsx: 4.21.0
 
-  vitest@3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3)):
+  vitest@3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(tsx@4.21.0):
     dependencies:
       '@types/chai': 5.2.3
       '@vitest/expect': 3.2.4
-      '@vitest/mocker': 3.2.4(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1))
+      '@vitest/mocker': 3.2.4(msw@2.12.13(@types/node@22.19.15)(typescript@5.9.3))(vite@7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0))
       '@vitest/pretty-format': 3.2.4
       '@vitest/runner': 3.2.4
       '@vitest/snapshot': 3.2.4
@@ -5176,8 +5205,8 @@ snapshots:
       tinyglobby: 0.2.15
       tinypool: 1.1.1
       tinyrainbow: 2.0.0
-      vite: 7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
-      vite-node: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)
+      vite: 7.3.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
+      vite-node: 3.2.4(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.31.1)(tsx@4.21.0)
       why-is-node-running: 2.3.0
     optionalDependencies:
       '@types/node': 22.19.15