Lain MCP Server

LAIN builds a map of how all the code in your project connects - what calls what, what depends on what, which files tend to change together. Then it lets your AI coding assistant ask questions about that map. So instead of the AI just looking at one file and guessing, it can ask "if I change this function, what else breaks?" and get a real answer. It plugs into any AI agent that supports MCP and runs in the…

People connecting coding agent tools to Claude, Cursor, VS Code, or another MCP client. The project is written in Rust.

VERIFIED ACTIVE

LAST COMMIT 2026-08-21 · ★ 6 · #71 OF 194 MAINTAINED CODING AGENT · VERIFIED 2026-08-25

MIT · Rust servers · how we verify → /methodology

01 · Install Lain

before you install - you'll need

Set LAIN_EMBEDDING_MODEL before connecting.

Claude Code

claude mcp add spuentesp-lain -- npx -y @spuentesp/lain-mcp

Claude Desktop / Cursor / VS Code - add to config

{
  "mcpServers": {
    "spuentesp-lain": {
      "command": "npx",
      "args": [
        "-y",
        "@spuentesp/lain-mcp"
      ]
    }
  }
}

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions

license MIT - declared in the repository

npm package @spuentesp/lain-mcp - published under the repo owner's npm scope (@spuentesp)

registry namespace io.github.spuentesp is GitHub-verified and matches the repo owner

03 · What Lain can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

Latest releases

v0.6.0 · 2026-08-20

v0.5.0 · 2026-08-11

Highlights · Two new first-class coding agents · OpenCode (--agent opencode): writes opencode.json (project) or ~/.config/opencode/opencode.json (user) with the verified mcp.<name> shape - type: "local", command…

v0.4.2 · 2026-08-07

04 · Who maintains Lain

lain is maintained by spuentesp. It's the only MCP server we track from this author; the repo dates to Apr 2026.

05 · Facts

repository: github.com/spuentesp/lain
category: coding agent - ranked #71 of 194 actively-maintained coding agent servers as of 2026-08-25.
release cadence: 6 releases in the last 90 days (latest 2026-08-20)
registry: io.github.spuentesp/lain (active, first published 2026-05-02)
packages: npm:@spuentesp/lain-mcp

06 · Lain FAQ

What is Lain?

Is Lain still maintained?

Yes - as of 2026-08-25, its last commit was 2026-08-21 and it shipped 6 releases in the last 90 days. We re-verify nightly.

How do I install Lain?

Run `npx -y @spuentesp/lain-mcp`. The README documents one environment variable (LAIN_EMBEDDING_MODEL) to set first. Set LAIN_EMBEDDING_MODEL before connecting. You can also paste the ready-made client config above.

Does Lain run locally?

Yes - it's a stdio server: it runs on your machine (via npx) with your user's permissions. Your data stays local unless the server itself calls external APIs.

07 · Alternatives to Lain

Alternatives to Lain

Maintained coding agent servers if Lain isn't the fit.

Pairs well with

Servers that cover what Lain doesn't - only shown when the pairing reason fits the companion.

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