---
title: "LangSmith A2A SendMessage supports non-blocking configuration: 2026-10-21 | Harbyn"
description: "LangSmith A2A SendMessage supports non-blocking configuration, announced Oct 21, 2026."
canonical: "https://harbyn.com/changes/langsmith/2026-10-21-a2a-sendmessage-supports-non-blocking-configuration"
last-updated: 2026-10-25
---

# LangSmith A2A SendMessage supports non-blocking configuration

Markdown version of <https://harbyn.com/changes/langsmith/2026-10-21-a2a-sendmessage-supports-non-blocking-configuration>.

Behavior change - LangSmith. low severity. In effect.

Setting configuration.returnImmediately to true, or the legacy blocking setting to false, returns the new task immediately with its submitted or working state so it can be polled with GetTask. Blocking remains the default. Non-boolean flag values return an invalid params error.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [LangSmith](https://harbyn.com/vendors/langsmith.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Oct 21, 2026 (undated by the vendor; the day it first appeared) |
| Added to Harbyn | Oct 25, 2026 |
| Lead time | No dated deadline |
| Symbols | `configuration.returnImmediately`, `blocking`, `GetTask` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses LangSmith, from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://docs.langchain.com/langsmith/changelog> (changelog, fetched 2026-10-21 14:31 UTC, sha256 `d39a828b21bd46938346d79499bbe68803acdbe628779a519db84c2fa1348e09`)

## Related changes

### More from LangSmith

- [BYOC sandboxes can use the full node](https://harbyn.com/changes/langsmith/2026-10-21-byoc-sandboxes-can-use-the-full-node.md) (Behavior change, announced Oct 21, 2026)
- [Context Hub webhook limit removed](https://harbyn.com/changes/langsmith/2026-10-21-context-hub-webhook-limit-removed.md) (Behavior change, announced Oct 21, 2026)
- [Engine permissions are split](https://harbyn.com/changes/langsmith/2026-10-21-engine-permissions-are-split.md) (Behavior change, announced Oct 21, 2026)
- [Engine pull requests are ready for review](https://harbyn.com/changes/langsmith/2026-10-21-engine-pull-requests-are-ready-for-review.md) (Behavior change, announced Oct 21, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: ORDER\_CHANGE notifications add PreFulfillmentStatusChange for Amazon Autos](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-3.md) (effective Oct 28, 2026)
- [BigCommerce: 301 redirects will apply only to storefront channels](https://harbyn.com/changes/bigcommerce/2026-10-07-301-redirects-now-apply-to-storefront-channels-only.md) (effective Nov 10, 2026)
- [GitHub: Secret scanning audit log business field changes to enterprise slug](https://harbyn.com/changes/github/2026-10-20-updates-to-github-secret-scanning-7.md) (effective Nov 12, 2026)
- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)