# @cursor/sdk 1.0.18 Unhandled promise rejection on session auth error crashes host process

**URL:** <https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620>\
**Category:** Bug Reports\
**Tags:** cursor-sdk, crashes\
**Created:** [June 19, 2026, 9:31am UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620 "2026-06-19T09:31:57Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![yaakov\_fg](https://avatars.discourse-cdn.com/v4/letter/y/3be4f8/32.png) [@yaakov\_fg](https://forum.cursor.com/u/yaakov_fg)\
**Post date:** [June 19, 2026, 9:31am UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620/1 "2026-06-19T09:31:57Z")

</div>

### Where does the bug appear (feature/product)?

Cursor SDK

### Describe the Bug

When using `@cursor/sdk` (^1.0.18) in a long-running Node.js service, if an Agent  
instance goes idle for approximately 30-44 minutes and then `agent.send()` is called  
again, the SDK’s internal gRPC stream processor throws a `ConnectError` (code 16 /  
UNAUTHENTICATED) as an **unhandled Promise rejection** that crashes the host process.

The error bypasses the SDK’s own `convertConnectError()` error conversion layer and  
never reaches the `run.wait()` Promise. The caller’s `try/catch` around `run.wait()`  
is never triggered. The raw `ConnectError` appears in a parallel internal Promise  
chain that the host application has no access to.

This makes it impossible to build a resilient long-running service with the SDK  
without relying on `process.on('unhandledRejection')` as a blunt safety net.

### Steps to Reproduce

1. Create an Agent: `const agent = await Agent.create({ apiKey, model, mode: "agent", local: { cwd, store, settingSources: ["project"] } })`
2. Send a message and wait for completion:

```typescript
const run = await agent.send("hello", { mcpServers });
const result = await run.wait(); // succeeds

```

3. Wait 30-45 minutes without any activity on this agent instance
4. Send another message on the SAME agent instance:

```typescript
try {
  const run2 = await agent.send("follow up", { mcpServers });
  const result2 = await run2.wait();
} catch (err) {
  // THIS CATCH NEVER FIRES
  console.error("caught:", err);
}

```

5. **Observed:** Node.js process exits with code 1. The `catch` block is never reached.

### Expected Behavior

- The `run.wait()` Promise should reject with an `AuthenticationError` (via the SDK’s `convertConnectError()` mapping)
- OR `agent.send()` should reject with `AuthenticationError`
- In either case, the caller’s `try/catch` should be able to handle the error gracefully
- The host process should NOT crash

### Operating System

MacOS

### Version Information

- `@cursor/sdk`: 1.0.18 (installed via `^1.0.18`)
- `@connectrpc/connect`: bundled with SDK (transport layer where error originates)
- Node.js: 20.12.2

### Additional Information

Stack trace of the unhandled rejection:

```auto
ConnectError: [unauthenticated] Error
    at errorFromJson (file:///.../node_modules/@connectrpc/connect/dist/esm/protocol-connect/error-json.js:53:19)
    at endStreamFromJson (file:///.../node_modules/@connectrpc/connect/dist/esm/protocol-connect/end-stream.js:64:11)
    at Object.parse (file:///.../node_modules/@connectrpc/connect/dist/esm/protocol-connect/end-stream.js:118:24)
    at file:///.../node_modules/@connectrpc/connect/dist/esm/protocol/async-iterable.js:399:75
    at Generator.next (<anonymous>)
    at resume (file:///.../node_modules/@connectrpc/connect/dist/esm/protocol/async-iterable.js:28:44)
    at fulfill (file:///.../node_modules/@connectrpc/connect/dist/esm/protocol/async-iterable.js:30:31)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

```

### Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

---

<div class="post-metadata">

**Author:** ![mohitjain](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/mohitjain/32/100229_2.png) [@mohitjain](https://forum.cursor.com/u/mohitjain)\
**Post date:** [June 19, 2026, 10:20am UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620/7 "2026-06-19T10:20:55Z")

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This is a known issue, and the host-process crash is already fixed.

The fix shipped in `@cursor/sdk` 1.0.19 (the current latest on npm). You’re on 1.0.18, which predates it, so upgrading should resolve the crash:

```auto
npm install @cursor/sdk@latest

```

One expectation to set: surfacing that underlying error as a typed, catchable error on `run.wait()` (so your `try/catch` receives an `AuthenticationError` instead of the run resolving with a bare `status: "error"`) is a separate improvement we’re still working on. After upgrading, a failed run may still resolve with `status: "error"` rather than throwing — but it won’t crash the process.

If you still see the process exit after moving to 1.0.19, reply here with the version and stack trace and I’ll dig in further.

---

<div class="post-metadata">

**Author:** ![yaakov\_fg](https://avatars.discourse-cdn.com/v4/letter/y/3be4f8/32.png) [@yaakov\_fg](https://forum.cursor.com/u/yaakov_fg)\
**Post date:** [June 19, 2026, 11:52am UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620/8 "2026-06-19T11:52:11Z")

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Thanks for the update. Would be nice if you could have detailed change logs for your different products so that folks are able to tell what is fixed and when (and not just a /changelog that is more like a blog)

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<div class="post-metadata">

**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\
**Post date:** [June 21, 2026, 11:52am UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620/10 "2026-06-21T11:52:47Z")

</div>

This topic was automatically closed 2 days after the last reply. New replies are no longer allowed.

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<div class="post-metadata">

**Author:** ![Colin](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/colin/32/90452_2.png) [@Colin](https://forum.cursor.com/u/Colin)\
**Post date:** [August 27, 2026, 1:06pm UTC](https://forum.cursor.com/t/cursor-sdk-1-0-18-unhandled-promise-rejection-on-session-auth-error-crashes-host-process/163620/14 "2026-08-27T13:06:45Z")

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Hi @yaakov_fg!

Happy to let you know that the issue should be fixed in the next cut of the Cursor SDK.