diff --git a/apps/sim/lib/execution/remote-sandbox/code-failure.test.ts b/apps/sim/lib/execution/remote-sandbox/code-failure.test.ts
new file mode 100644
index 00000000000..fdec0aac400
--- /dev/null
+++ b/apps/sim/lib/execution/remote-sandbox/code-failure.test.ts
@@ -0,0 +1,193 @@
+import { describe, expect, it } from 'vitest'
+import { processCodeFailure } from '@/lib/execution/remote-sandbox/code-failure'
+
+/** Node 22's crash report when `fetch` loses its socket before any response bytes. */
+const FETCH_SOCKET_CLOSED = `node:internal/deps/undici/undici:13510
+      Error.captureStackTrace(err);
+            ^
+
+TypeError: fetch failed
+    at node:internal/deps/undici/undici:13510:13
+    at async file:///home/user/.sim-function-abc.mjs:1:1 {
+  [cause]: SocketError: other side closed
+      at Socket.<anonymous> (node:internal/deps/undici/undici:6294:28)
+      at process.processTicksAndRejections (node:internal/process/task_queues:90:21) {
+    code: 'UND_ERR_SOCKET',
+    socket: {
+      remotePort: 443,
+      timeout: undefined,
+      bytesWritten: 171,
+      bytesRead: 0
+    }
+  }
+}
+
+Node.js v22.19.0
+`
+
+/** An error carrying its own properties, which Node prints indented after the stack. */
+const CUSTOM_ERROR_WITH_PROPERTIES = `file:///home/user/.sim-function-abc.mjs:1
+throw new QuotaExceeded('over quota')
+^
+
+QuotaExceeded: over quota
+    at file:///home/user/.sim-function-abc.mjs:1:109 {
+  limit: 5
+}
+
+Node.js v22.19.0
+`
+
+const NODE_CODED_ERROR = `node:internal/modules/package_json_reader:266
+  throw new ERR_MODULE_NOT_FOUND(packageName, fileURLToPath(base), null);
+        ^
+
+Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'left-pad' imported from /home/user/.sim-function-abc.mjs
+    at packageResolve (node:internal/modules/esm/resolve:767:81) {
+  code: 'ERR_MODULE_NOT_FOUND'
+}
+
+Node.js v22.19.0
+`
+
+/** An error printed without a stack (here a rejected `Promise.any`), bracketed by Node. */
+const STACKLESS_ERROR = `node:internal/modules/run_main:123
+    triggerUncaughtException(
+    ^
+
+[AggregateError: All promises were rejected] {
+  [errors]: [
+    Error: a
+        at file:///home/user/.sim-function-abc.mjs:1:35,
+    Error: b
+        at file:///home/user/.sim-function-abc.mjs:1:67
+  ]
+}
+
+Node.js v22.19.0
+`
+
+/** A thrown non-error leaves only Node's source-location header, which is not an error name. */
+const THROWN_STRING = `
+node:internal/modules/run_main:123
+    triggerUncaughtException(
+    ^
+just a string
+(Use \`node --trace-uncaught ...\` to show where the exception was thrown)
+
+Node.js v22.19.0
+`
+
+/** A thrown non-error object Node labels in brackets, like an error printed without a stack. */
+const THROWN_NULL_PROTOTYPE_OBJECT = `
+node:internal/modules/run_main:123
+    triggerUncaughtException(
+    ^
+[Object: null prototype] {
+  alpha: 'x',
+  gamma: 3
+}
+
+Node.js v22.19.0
+`
+
+const THROWN_FUNCTION = `
+node:internal/modules/run_main:123
+    triggerUncaughtException(
+    ^
+[Function: myHandler]
+
+Node.js v22.19.0
+`
+
+const STACKLESS_RANGE_ERROR = `file:///home/user/.sim-function-abc.mjs:1
+throw e
+^
+
+[RangeError: limit hit]
+
+Node.js v22.19.0
+`
+
+const STACKLESS_PLAIN_ERROR = `file:///home/user/.sim-function-abc.mjs:1
+throw e
+^
+
+[Error: plain failure]
+
+Node.js v22.19.0
+`
+
+const STACKLESS_ERROR_WITH_INLINE_PROPERTIES = `file:///home/user/.sim-function-abc.mjs:1
+throw e
+^
+
+[TypeError: bad thing] { code: 'E1' }
+
+Node.js v22.19.0
+`
+
+const STACKLESS_MULTILINE_ERROR = `file:///home/user/.sim-function-abc.mjs:1
+throw e
+^
+
+[TypeError: first line
+second line] {
+  code: 'E2'
+}
+
+Node.js v22.19.0
+`
+
+const PYTHON_TRACEBACK = `Traceback (most recent call last):
+  File "/home/user/.sim-function-abc.py", line 2, in <module>
+    raise QuotaExceeded('over quota')
+__main__.QuotaExceeded: over quota
+`
+
+describe('processCodeFailure', () => {
+  it.each([
+    ['a fetch that lost its socket', FETCH_SOCKET_CLOSED, 'TypeError', 'fetch failed'],
+    [
+      'an error with its own properties',
+      CUSTOM_ERROR_WITH_PROPERTIES,
+      'QuotaExceeded',
+      'over quota',
+    ],
+    [
+      "Node's coded error",
+      NODE_CODED_ERROR,
+      'Error [ERR_MODULE_NOT_FOUND]',
+      "Cannot find package 'left-pad' imported from /home/user/.sim-function-abc.mjs",
+    ],
+    [
+      'an error printed without a stack',
+      STACKLESS_ERROR,
+      'AggregateError',
+      'All promises were rejected',
+    ],
+    ['a stackless error with no properties', STACKLESS_RANGE_ERROR, 'RangeError', 'limit hit'],
+    ['a stackless plain Error', STACKLESS_PLAIN_ERROR, 'Error', 'plain failure'],
+    [
+      'a stackless error with inline properties',
+      STACKLESS_ERROR_WITH_INLINE_PROPERTIES,
+      'TypeError',
+      'bad thing',
+    ],
+    ['a stackless multiline error', STACKLESS_MULTILINE_ERROR, 'TypeError', 'first line'],
+    ['a thrown string', THROWN_STRING, 'Error', 'Execution failed'],
+    ['a thrown null-prototype object', THROWN_NULL_PROTOTYPE_OBJECT, 'Error', 'Execution failed'],
+    ['a thrown function', THROWN_FUNCTION, 'Error', 'Execution failed'],
+    ['a Python traceback', PYTHON_TRACEBACK, '__main__.QuotaExceeded', 'over quota'],
+  ])('names the error of %s from its headline', (_case, stderr, name, value) => {
+    const { error } = processCodeFailure({ stdout: '', stderr, exitCode: 1 })
+
+    expect(error).toEqual({ name, value, traceback: stderr })
+  })
+
+  it('reads the traceback from stdout when stderr is empty', () => {
+    const { error } = processCodeFailure({ stdout: PYTHON_TRACEBACK, stderr: '', exitCode: 1 })
+
+    expect(error?.name).toBe('__main__.QuotaExceeded')
+  })
+})
diff --git a/apps/sim/lib/execution/remote-sandbox/code-failure.ts b/apps/sim/lib/execution/remote-sandbox/code-failure.ts
index a7cc62f873e..d4a3ae80f3f 100644
--- a/apps/sim/lib/execution/remote-sandbox/code-failure.ts
+++ b/apps/sim/lib/execution/remote-sandbox/code-failure.ts
@@ -1,16 +1,31 @@
 import type { SandboxCodeResult, SandboxCommandResult } from '@/lib/execution/remote-sandbox/types'
 
+/**
+ * A top-level error headline in a Python traceback or Node crash report: `Name: message`,
+ * Node's `Name [CODE]: message`, or `[NameError: message]` (any inline properties after it)
+ * for an error printed without a stack. It starts the line, so the properties Node prints indented beneath an error
+ * (`code: 'X'`, `bytesRead: 0`) never match, and a space follows the colon, so
+ * source-location headers (`node:internal/x:12`, `file:///x.mjs:3`) don't either. The
+ * bracketed form needs an error-type name, since Node brackets other thrown values the
+ * same way (`[Object: null prototype] {`, `[Function: handler]`).
+ */
+const ERROR_HEADLINE =
+  /^(?:\[(?:[A-Za-z_$][\w.$]*)?(?:Error|Exception)|[A-Za-z_$][\w.$]*(?: \[[\w.$-]+\])?):(?:\s|$)/
+
 /**
  * Converts a failed code command into a code result, naming the error from the
- * last `Name: message` line of the traceback (stderr, else stdout).
+ * last error headline of the traceback (stderr, else stdout).
  */
 export function processCodeFailure(result: SandboxCommandResult): SandboxCodeResult {
   const traceback = result.stderr || result.stdout
-  const errorLine = traceback
+  const headline = traceback
     .split('\n')
     .reverse()
-    .find((line) => /^[A-Za-z_$][\w.$]*(?:Error|Exception|Interrupt|Exit)?:\s*/.test(line.trim()))
-    ?.trim()
+    .find((line) => ERROR_HEADLINE.test(line))
+  // A bracketed headline closes on this line, or on a later one for a multiline message.
+  const errorLine = (
+    headline?.startsWith('[') ? headline.slice(1).replace(/\](?: \{.*)?$/, '') : headline
+  )?.trim()
   const separator = errorLine?.indexOf(':') ?? -1
   const parsedErrorLine = errorLine ?? ''
   const name = separator > 0 ? parsedErrorLine.slice(0, separator) : 'Error'