---
title: "LangSmith Cancelled runs expose a cancellation reason: 2026-10-14 | Harbyn"
description: "LangSmith Cancelled runs expose a cancellation reason, announced Oct 14, 2026."
canonical: "https://harbyn.com/changes/langsmith/2026-10-14-cancelled-runs-expose-a-cancellation-reason"
last-updated: 2026-10-14
---

# LangSmith Cancelled runs expose a cancellation reason

Markdown version of <https://harbyn.com/changes/langsmith/2026-10-14-cancelled-runs-expose-a-cancellation-reason>.

Behavior change - LangSmith. low severity. In effect.

Cancelled runs now report why in cancel\_reason, and the thread error field holds only real failures. Paused threads whose run is cancelled or rolled back before its first checkpoint now stay interrupted instead of showing idle while interrupts are pending.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [LangSmith](https://harbyn.com/vendors/langsmith.md) |
| Kind | Behavior change |
| Severity | low |
| Status | In effect |
| Announced | Oct 14, 2026 (undated by the vendor; the day it first appeared) |
| Added to Harbyn | Oct 14, 2026 |
| Lead time | No dated deadline |
| Symbols | `cancel_reason` |
| 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 2026-10-14 17:17 UTC, sha256 `8b8952150ef8c1a6fb4c079e816ed4c7a61dea3642cff295155c073139c9a85b`)

## Related changes

### More from LangSmith

- [Agent list cursors from before the ordering change are rejected](https://harbyn.com/changes/langsmith/2026-10-14-agent-list-cursors-from-before-the-ordering-change-are-rejected.md) (Behavior change, announced Oct 14, 2026)
- [Deployment log requests read at most five backend pages](https://harbyn.com/changes/langsmith/2026-10-14-deployment-log-requests-read-at-most-five-backend-pages.md) (Behavior change, announced Oct 14, 2026)
- [MCP tunnel requests preserve authentication headers](https://harbyn.com/changes/langsmith/2026-10-14-mcp-tunnel-requests-preserve-authentication-headers.md) (Behavior change, announced Oct 14, 2026)
- [OpenTelemetry attributes outside the LangSmith schema are stored in run metadata](https://harbyn.com/changes/langsmith/2026-10-14-opentelemetry-attributes-outside-the-langsmith-schema-are-stored-in-run-metadata.md) (Behavior change, announced Oct 14, 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)