Short answers to common questions. For setup problems in a particular client, see Troubleshooting.
Do I need an account, an API key or OAuth?
No. The server is public and has no sign-in of any kind. If a client asks how to authenticate, choose none. Security and Privacy explains why.
Does it cost anything?
No. There is no account or key, so there is nothing to pay for. Each IP address can make 600 requests a minute; Limits and Errors lists the rest.
Which mindc release does it cover?
The release in the current index, named in three places: the version field of every lookup_symbol result, the mind://about resource, and _meta["dev.mindlang/index"].release in the server/discover result. At the time of writing it is mindc 0.10.2. Standard-library signatures come from that release's sources, not from a development branch.
How fresh is the index?
The index is built from a snapshot of the mindlang.dev docs and the pinned public releases, and ships with each update of the server. mind://about shows the build id and the snapshot date. A docs page published after that date is not in the index yet; read it on mindlang.dev.
Can it compile or check my code?
Not today. The server only reads the docs, the standard library and the error reference. Compile and check code with mindc on your own machine, then use explain_error on the codes it reports.
Why did search return mode: "lexical"?
Search matches by meaning and by keyword, and reports mode: "hybrid". When the embedding model is unavailable, or one client sends more than 30 searches a minute, it matches by keyword alone instead of failing, and reports mode: "lexical". The passages and their citations are correct in both modes, and nothing in your setup needs to change. See Tools Reference.
Why does GET /mcp return 405, and why does my /sse URL fail?
The server speaks Streamable HTTP, where every message is a POST. It never opens a server-sent event stream, so a GET gets 405. The older HTTP+SSE transport, which MCP has retired, was never served here, and a /sse URL answers 404. Use https://mcp.mindlang.dev/mcp with the client's HTTP (Streamable HTTP) option. The route table has every path.
My client lists the server but shows no tools
Usually the client read the URL under the wrong configuration key or transport. Troubleshooting lists the keys each client expects.
Does the server see my code or files?
Only what your client sends in a request: a search query, a symbol name, an error code, or the code you pass to the port_to_mind prompt. It is used to answer that request and is not stored. The server cannot reach your files. What is recorded lists the counts it keeps.
Is there a local version?
There is one server, hosted at https://mcp.mindlang.dev/mcp. A client that can only start local (stdio) servers reaches it through a small bridge, shown under Claude Desktop (JSON config).
Related pages
- MCP Server: setup for every client
- Tools Reference: what each tool takes and returns
- Limits and Errors: limits, error codes and routes
- Changelog: what changed in each server version