Docs by LangChain
Developer tools Listed by MCPBaySearch LangChain, LangGraph and LangSmith documentation with code examples and API reference
By: LangChain
The connection URL lives in your cabinet. Use "Add" above, then open "My MCPs" — the address for your AI client appears there.
About
The official documentation MCP server for LangChain's docs site. It lets an assistant answer questions about LangChain, LangGraph and LangSmith from the current documentation rather than from older training data — useful because these libraries change quickly.
Tools:
- search_docs_by_lang_chain — searches the documentation and returns relevant passages with links.
- query_docs_filesystem_docs_by_lang_chain — reads documentation pages directly when a full page is needed.
- submit_feedback — sends feedback about the docs back to the LangChain team.
Typical use: "How do I add human-in-the-loop interrupts to a LangGraph agent in Python?" — the assistant finds the current guide and answers with up-to-date code.
Who it is for: developers building LLM applications and agents with the LangChain ecosystem.
Notes: free, no account needed. Read-only access to public documentation.
Tools (3)
query_docs_filesystem_docs_by_lang_chainRun a read-only shell-like query against a virtualized, in-memory filesystem rooted at `/` that contains ONLY the Docs by LangChain documentation pages and OpenAPI specs. This is NOT a shell on any real machine — nothing runs on the user's computer, the server host, or any network. The filesystem is a sandbox backed by documentation chunks. This is how you read documentation pages: there is no separate "get page" tool. To read a page, pass its `.mdx` path to `head` or `cat` — a page at the URL path `/some/page` lives at `/some/page.mdx`. To search the docs with exact keyword or regex matches, use `rg`. To understand the docs structure, use `tree` or `ls`. **Paths are specific to this site — never guess them.** Discover real paths with `tree / -L 2`, `ls /`, or the search tool before reading. If a path does not exist, that only means the guess was wrong; it does NOT mean the topic is undocumented — use `rg -il "keyword" /` to find where it is covered. **Workflow:** Start with the search tool for broad or conceptual queries like "how to authenticate" or "rate limiting". Use this tool when you need exact keyword/regex matching, structural exploration, or to read the full content of a specific page by path. Supported commands: rg (ripgrep), grep, find, tree, ls, cat, head, tail, stat, wc, sort, uniq, cut, sed, awk, jq, plus basic text utilities. No writes, no network, no process control. Run `--help` on any command for usage. Each call is STATELESS: the working directory always resets to `/` and no shell variables, aliases, or history carry over between calls. If you need to operate in a subdirectory, chain commands in one call with `&&` or pass absolute paths (e.g., `cd /some-directory && ls` or `ls /some-directory`). Do NOT assume that `cd` in one call affects the next call. Examples (replace the placeholder paths with real ones from `tree` or search): - `tree / -L 2` — see the top-level directory layout - `rg -il "rate limit" /` — find all files mentioning "rate limit" - `rg -C 3 "apiKey" /some-directory/` — show matches with 3 lines of context around each hit - `head -80 /some/page.mdx` — read the top 80 lines of a specific page - `head -80 /page-one.mdx /page-two.mdx /section/page-three.mdx` — read multiple pages in one call - `cat /some/page.mdx` — read a full page when you need everything - `cat /openapi/langsmith/langsmith-platform-openapi.json | jq '.paths | keys'` — list OpenAPI endpoints OpenAPI specs for this site are mounted at: `/openapi/langsmith/langsmith-platform-openapi.json`, `'/openapi/https://api.host.langchain.com/openapi.json'`, `/openapi/langsmith/agent-server-openapi.json`. Use them to answer questions about endpoints, request/response schemas, parameters, and authentication. Output is truncated to 30KB per call. Prefer targeted `rg -C` or `head -N` over broad `cat` on large files. To read only the relevant sections of a large file, use `rg -C 3 "pattern" /path/file.mdx`. Batch multiple file reads into a single `head` or `cat` call whenever possible. When referencing pages in your response to the user, convert filesystem paths to URL paths by removing the `.mdx` extension. For example, `/some/page.mdx` becomes `/some/page`.
Search documentationSearch across the Docs by LangChain knowledge base to find relevant information, code examples, API references, and guides. Use this tool when you need to answer questions about Docs by LangChain, find specific documentation, understand how features work, or locate implementation details. The search returns contextual content with titles and direct links to the documentation pages. If you need the full content of a specific page, use the query_docs_filesystem tool to `head` or `cat` the page path (append `.mdx` to the path returned from search — e.g. a result at `/some/page` is read with `head -200 /some/page.mdx`).
Submit documentation feedbackReport a problem with this documentation site so the docs team can fix it. Use when a documentation page is incorrect, outdated, confusing, incomplete, or has a broken example. This is for feedback about the documentation content itself — not for product support requests or feedback about this tool or assistant.