langsmith-mcp

LangChain Plugins

The official marketplace of LangChain ecosystem plugins for your coding agent. Add it once, then install skills and MCP servers that help you build with LangChain, LangGraph, and Deep Agents — and observe and evaluate your apps with LangSmith.

Works with deepagents-code (dcode), Claude Code, and OpenAI Codex.

What's inside

Plugin	What you get	Use it when
langchain-skills	Skills for building agents with LangChain, LangGraph, and Deep Agents — models, tools, RAG, streaming, middleware, persistence, HITL, and more	You're writing or debugging LangChain / LangGraph / Deep Agents code
langsmith-skills	Skills for tracing, building datasets, and running evaluations with LangSmith	You're debugging a run or setting up evals
langchain-mcp	Live LangChain Docs and API Reference MCP servers	You want your agent to look up current docs and API signatures
langsmith-mcp	The LangSmith MCP server — query your traces, datasets, prompts, and experiments from your agent	You want your agent to read your LangSmith workspace

Install

1. Add the marketplace

deepagents-code (dcode)

dcode plugin marketplace add langchain-ai/langchain-plugins

Claude Code

/plugin marketplace add langchain-ai/langchain-plugins

OpenAI Codex

codex plugin marketplace add langchain-ai/langchain-plugins

2. Install the plugins you want

Plugin IDs use the form plugin-name@langchain-plugins. Install any subset:

deepagents-code (dcode)

dcode plugin install langchain-skills@langchain-plugins
dcode plugin install langsmith-skills@langchain-plugins
dcode plugin install langchain-mcp@langchain-plugins
dcode plugin install langsmith-mcp@langchain-plugins

Then run /reload or start a new session.

Claude Code

/plugin install langchain-skills@langchain-plugins
/plugin install langsmith-skills@langchain-plugins
/plugin install langchain-mcp@langchain-plugins
/plugin install langsmith-mcp@langchain-plugins

OpenAI Codex (note: Codex uses add, not install)

codex plugin add langchain-skills@langchain-plugins
codex plugin add langsmith-skills@langchain-plugins
codex plugin add langchain-mcp@langchain-plugins
codex plugin add langsmith-mcp@langchain-plugins

Using the plugins

Skills activate automatically when your request matches what a skill covers — ask your agent to "build a LangGraph agent" or "help me set up a LangSmith eval" and the relevant skill kicks in. You can also invoke one explicitly (e.g. in dcode: /skill:langchain-skills@langchain-plugins:langchain-rag).

MCP servers become available once their plugin is enabled:

Server	Gives your agent	Sign-in
langchain-docs	Live LangChain / LangGraph / LangSmith documentation	None
langchain-reference	Up-to-date API reference lookups	None
langsmith	Read access to your traces, datasets, prompts, and experiments	LangSmith account (OAuth)

The LangSmith server signs in with OAuth — there are no API keys to paste. If your LangSmith workspace is in the EU, APAC, or AWS regions, point the server at your regional host per the LangSmith Remote MCP docs.

Requirements

• A supported agent CLI: deepagents-code, Claude Code, or OpenAI Codex.
• A LangSmith account — only needed for the langsmith-mcp plugin.

Staying current

The skill plugins track their upstream LangChain releases and are refreshed automatically, so installing from this marketplace keeps you on the latest published versions. Run your agent's marketplace update command periodically to pick up new releases: