Why is mcpdoc (LangChain) not working in Claude Code?

It failed in our test on Oct 15, 2026. Errors we observed: no successful call to this server's tools; answer missing ['5173']; no tool result containing ['5173']

mcpdoc (LangChain) not working in Claude Code? Fixes

Failed It failed in our test on Oct 15, 2026. Below is the exact setup we used in Claude Code (2.1.296 (Claude Code)), every error we saw, and what to check, all from our own run log.

Date tested: Oct 15, 2026 · From our harness, not the maker’s claims · How we test

1. Use the install config we tested in Claude Code

claude mcp add -s local mcpdoc -- uvx --from mcpdoc mcpdoc --urls Vite:https://vite.dev/llms.txt --transport stdio

Replace any <YOUR_…> placeholder and local test paths with your own. Every client’s tested snippet is on the mcpdoc (LangChain) page.

2. Check that Claude Code connects to it

In our run the connect check was failed. Our check output:

mcpdoc: uvx --from mcpdoc mcpdoc --urls Vite:https://vite.dev/llms.txt --transport stdio - ✘ Failed to connect — CONNECTION_CLOSED: Connection closed

Errors we observed

agent task: docs fact: no successful call to this server's tools; answer missing ['5173']; no tool result containing ['5173']

Quoted from our run log. Secrets redacted. We list only what we saw.

More help

mcpdoc (LangChain): all results and setup · Full Claude Code run · General Claude Code MCP troubleshooting