diff --git a/packages/js-sdk/tests/sandbox/commands/sendStdin.test.ts b/packages/js-sdk/tests/sandbox/commands/sendStdin.test.ts
index 56bcd025a..b6914fc67 100644
--- a/packages/js-sdk/tests/sandbox/commands/sendStdin.test.ts
+++ b/packages/js-sdk/tests/sandbox/commands/sendStdin.test.ts
@@ -7,7 +7,6 @@ sandboxTest('send stdin to process', async ({ sandbox }) => {
 
   await sandbox.commands.sendStdin(cmd.pid, text)
 
-
   for (let i = 0; i < 5; i++) {
     if (cmd.stdout === text) {
       break
@@ -64,6 +63,5 @@ sandboxTest('send multiline string to stdin', async ({ sandbox }) => {
 
   await cmd.kill()
 
-
   assert.equal(cmd.stdout, text)
 })
diff --git a/packages/js-sdk/tests/sandbox/connect.test.ts b/packages/js-sdk/tests/sandbox/connect.test.ts
index 7311713a3..d5eb1b213 100644
--- a/packages/js-sdk/tests/sandbox/connect.test.ts
+++ b/packages/js-sdk/tests/sandbox/connect.test.ts
@@ -1,4 +1,4 @@
-import { test, assert } from 'vitest'
+import { assert, test } from 'vitest'
 
 import { Sandbox } from '../../src'
 import { isDebug, template } from '../setup.js'
@@ -19,3 +19,25 @@ test('connect', async () => {
     }
   }
 })
+
+test('connect to non-running sandbox', async () => {
+  const sbx = await Sandbox.create(template, { timeoutMs: 10_000 })
+  let isKilled = false
+
+  try {
+    const isRunning = await sbx.isRunning()
+    assert.isTrue(isRunning)
+    await sbx.kill()
+    isKilled = true
+
+    const sbxConnection = await Sandbox.connect(sbx.sandboxId)
+    const isRunning2 = await sbxConnection.isRunning()
+    assert.isFalse(isRunning2)
+
+    await sbxConnection.commands.run('echo "hello"')
+  } finally {
+    if (!isKilled) {
+      await sbx.kill()
+    }
+  }
+})
diff --git a/packages/js-sdk/tests/sandbox/host.test.ts b/packages/js-sdk/tests/sandbox/host.test.ts
index 3ff7c6964..80072149e 100644
--- a/packages/js-sdk/tests/sandbox/host.test.ts
+++ b/packages/js-sdk/tests/sandbox/host.test.ts
@@ -2,30 +2,56 @@ import { assert } from 'vitest'
 
 import { isDebug, sandboxTest, wait } from '../setup.js'
 
-sandboxTest('ping server in sandbox', async ({ sandbox }) => {
-  const cmd = await sandbox.commands.run('python -m http.server 8000', { background: true })
+sandboxTest.skipIf(isDebug)(
+  'ping server in running sandbox',
+  async ({ sandbox }) => {
+    const cmd = await sandbox.commands.run('python -m http.server 8000', {
+      background: true,
+    })
 
-  try {
-    await wait(1000)
+    try {
+      await wait(1000)
 
-    const host = sandbox.getHost(8000)
+      const host = sandbox.getHost(8000)
 
-    let res = await fetch(`${isDebug ? 'http' : 'https'}://${host}`)
+      let res = await fetch(`${isDebug ? 'http' : 'https'}://${host}`)
 
-    for (let i = 0; i < 20; i++) {
-      if (res.status === 200) {
-        break
-      }
+      for (let i = 0; i < 20; i++) {
+        if (res.status === 200) {
+          break
+        }
 
-      res = await fetch(`${isDebug ? 'http' : 'https'}://${host}`)
-      await wait(500)
-    }
-    assert.equal(res.status, 200)
-  } finally {
-    try {
-      await cmd.kill()
-    } catch (e) {
-      console.error(e)
+        res = await fetch(`${isDebug ? 'http' : 'https'}://${host}`)
+        await wait(500)
+      }
+      assert.equal(res.status, 200)
+    } finally {
+      try {
+        await cmd.kill()
+      } catch (e) {
+        console.error(e)
+      }
     }
+  },
+  60_000
+)
+
+sandboxTest.skipIf(isDebug)(
+  'ping server in non-running sandbox',
+  async ({ sandbox }) => {
+    const host = sandbox.getHost(49983)
+    const url = `${isDebug ? 'http' : 'https'}://${host}/health`
+
+    const res = await fetch(url)
+
+    assert.equal(res.status, 204)
+
+    await sandbox.kill()
+
+    const res2 = await fetch(url)
+    assert.equal(res2.status, 502)
+
+    const text = await res2.text()
+    assert.equal(text, 'Sandbox not found')
   }
-}, 60_000 )
+)