fix: support MCP json schema tools

apps/desktop/package.json

@@ -61,6 +61,7 @@
     "@sigstore/bundle": "5.0.0",
     "@sigstore/tuf": "5.0.0",
     "@sigstore/verify": "4.1.2",
+    "ajv": "^8.20.0",
     "electron-updater": "^6.8.9",
     "node-pty": "^1.2.0-beta.15",
     "qrcode": "^1.5.4",
@@ -84,6 +85,7 @@
     "@types/react-dom": "^19.2.4",
     "@types/ws": "^8.18.1",
     "@vitejs/plugin-react": "^6.1.0",
+    "ai": "7.0.70",
     "@xterm/addon-fit": "^0.11.0",
     "@xterm/xterm": "^6.0.0",
     "electron": "43.4.1",

apps/desktop/src/main/__tests__/runtime-host-desktop-candidate.test.ts

@@ -544,30 +544,29 @@ test('rolls back only candidate-owned IPC after a registration collision', async
   assert.equal(host.closeCalls, 1);
 });
 
-test('closes the claimed Host connection when native capability construction fails', async () => {
+test('does not drop the Host connection when a native tool schema is invalid', async () => {
+  // Per-tool isolation: one bad tool is skipped and the provider still
+  // constructs, so the Host connection stays alive.
   const ipc = ipcHarness();
   const host = connectionHarness('invalid-capability');
   const invalidTool = {
     ...nativeTool(),
     parameters: z.string(),
   } as unknown as MakaTool;
 
-  await assert.rejects(
-    () =>
-      createDesktopRuntimeHostCandidate(
-        host.connection,
-        deps(ipc, {
-          browserTools: [invalidTool],
-          resolveBrowserUrl: () => 'https://example.com/',
-          releaseBrowserSession() {},
-          computerUseTools: emptyComputerUseTools(),
-          releaseComputerUseSession() {},
-        }),
-      ),
-    /tool schema must be an object/,
+  const candidate = await createDesktopRuntimeHostCandidate(
+    host.connection,
+    deps(ipc, {
+      browserTools: [invalidTool],
+      resolveBrowserUrl: () => 'https://example.com/',
+      releaseBrowserSession() {},
+      computerUseTools: emptyComputerUseTools(),
+      releaseComputerUseSession() {},
+    }),
   );
 
-  assert.equal(ipc.size, 0);
+  assert.equal(host.closeCalls, 0);
+  await candidate.close();
   assert.equal(host.closeCalls, 1);
 });