---
name: LangChain Changelog
slug: langchain-changelog
type: scrape
source_url: https://changelog.langchain.com
organization: LangChain
organization_slug: langchain
total_releases: 10
latest_date: 2026-03-19
last_updated: 2026-04-16
tracking_since: 2025-12-10
canonical: https://releases.sh/langchain/langchain-changelog
organization_url: https://releases.sh/langchain
---

<Summary type="rolling" window-days="90" release-count="7">
LangSmith shifted focus toward agent observability and collaboration tooling. The platform expanded baseline comparison to persist across experiment runs rather than require manual selection each time, and introduced unified cost tracking across the entire agent stack—moving beyond just LLM call accounting. Agent Builder (renamed to LangSmith Fleet in March) added collaborative features like a central chat interface, file uploads, and a shared tool registry, while the Insights Agent graduated to scheduled execution on custom cadences, eliminating manual report triggers. Deep Agents v0.4 shipped pluggable sandbox support and smarter conversation history summarization as the foundation for more complex agentic workflows.
</Summary>

<Summary type="monthly" period="March 2026" release-count="1">
LangSmith Fleet launched, replacing Agent Builder with a unified platform for deploying and managing agentic applications at scale.
</Summary>

<Release date="March 19, 2026" published="2026-03-19T00:00:00.000Z" url="https://changelog.langchain.com#agent-builder-is-now-langsmith-fleet">
## Agent Builder is now LangSmith Fleet

LangSmith Agent Builder has been renamed to LangSmith Fleet. The new name is reflected across the platform.
</Release>

<Release date="February 19, 2026" published="2026-02-19T00:00:00.000Z" url="https://changelog.langchain.com#pin-a-baseline-experiment-in-langsmith">
## Pin a baseline experiment in LangSmith

You can now pin any experiment as your baseline, so every subsequent run is automatically measured against it. Instead of manually selecting experiments for comparison, your chosen baseline persists across all future runs.
</Release>

<Release date="February 18, 2026" published="2026-02-18T00:00:00.000Z" url="https://changelog.langchain.com#agent-builder-chat-file-uploads-and-tool-registry">
## Agent Builder: chat, file uploads, and tool registry

Agent Builder enhancements centered around collaboration. There's now a central Chat agent with access to file uploads and a tool registry, making working with an agent feel like working with a teammate.
</Release>

<Release date="February 17, 2026" published="2026-02-17T00:00:00.000Z" url="https://changelog.langchain.com#scheduled-reports-for-insights-agent">
## Scheduled reports for Insights Agent

The LangSmith Insights Agent now runs on your schedule, no manual triggers required. Set a recurring cadence (daily, weekly, or a custom cron expression) and the agent generates reports automatically.
</Release>

<Release version="v0.4" date="February 10, 2026" published="2026-02-10T00:00:00.000Z" url="https://changelog.langchain.com#v0-4">
## Deep Agents v0.4

deepagents v0.4 ships pluggable sandbox support, smarter conversation history summarization, and Responses API as the default for OpenAI models. Agents now have enhanced capabilities for complex tasks.
</Release>

<Release version="v0.13.10" date="February 6, 2026" published="2026-02-06T00:00:00.000Z" url="https://changelog.langchain.com#v0-13-10">
## Customize trace previews in LangSmith

You can now configure which parts of a trace's inputs and outputs appear directly in the tracing table. This is especially useful for projects with custom data structures.
</Release>

<Release date="February 5, 2026" published="2026-02-05T00:00:00.000Z" url="https://changelog.langchain.com#track-costs-across-your-entire-agent-stack">
## Track costs across your entire agent stack

LangSmith now gives you a unified view of costs across your full agent workflow, not just LLM calls. Submit custom cost metadata for any run, whether that's API calls, compute, or other expenses.
</Release>

<Release version="v0.13" date="January 16, 2026" published="2026-01-16T00:00:00.000Z" url="https://changelog.langchain.com#v0-13">
## LangSmith Self-Hosted v0.13

This self-hosted release expands feature parity with LangSmith Cloud while improving performance, security, and operational control. It brings Insights and other cloud features to self-hosted deployments.
</Release>

<Release version="v0.12.61" date="December 17, 2025" published="2025-12-17T00:00:00.000Z" url="https://changelog.langchain.com#v0-12-61">
## Pairwise annotation queues for comparing agent outputs

Pairwise Annotation Queues in LangSmith are a fast, structured way to compare two agent outputs side-by-side and pick a winner. This makes scoring subjective tasks more efficient.
</Release>

<Release date="December 10, 2025" published="2025-12-10T00:00:00.000Z" url="https://changelog.langchain.com#langsmith-fetch-debug-agents-from-your-terminal">
## LangSmith Fetch: Debug agents from your terminal

LangSmith Fetch is a new CLI tool that brings full LangSmith trace access directly into your terminal, coding environment, or IDE, enabling seamless debugging workflows for agent builders.
</Release>