Connect Zed to Semlith over MCP

How to connect Zed to Semlith over MCP, the command or file that adds it, and how to check the connection works.

Every stanza writes ${SEMLITH_BIN} where the binary goes, the path which semlith prints. Set up your agent client explains it and the HTTP form.

Zed — ~/.config/zed/settings.json on macOS and Linux ($XDG_CONFIG_HOME/zed when that is set, and ~/.var/app/dev.zed.Zed/config/zed for the Flatpak), and %APPDATA%\Zed\settings.json on Windows; the zed: open settings file command opens whichever it is. Zed calls MCP servers context servers, under context_servers. Its remote support has moved between versions and older builds start local processes only, so this is the stdio form, which needs no key: semlith mcp proxies to the running daemon. Zed has no registration CLI, so semlith setup --register-all writes the entry into that file.

Zed allows comments and trailing commas in settings.json, which a strict JSON parser rejects. When the file has either, semlith leaves it untouched and prints the stanza below with the reason, for you to paste in.

~/.config/zed/settings.json (macOS and Linux)

{
  "context_servers": {
    "semlith": {
      "source": "custom",
      "command": "${SEMLITH_BIN}",
      "args": ["mcp"]
    }
  }
}

%APPDATA%\Zed\settings.json (Windows)

{
  "context_servers": {
    "semlith": {
      "source": "custom",
      "command": "${SEMLITH_BIN}",
      "args": ["mcp"]
    }
  }
}

Its user-level instructions file, read on every session, to which semlith setup --register-all appends the rule block — see https://github.com/zed-industries/zed/blob/main/docs/src/ai/rules.md.

~/.config/zed/AGENTS.md (macOS and Linux)

${SEMLITH_RULES}

%APPDATA%\Zed\AGENTS.md (Windows)

${SEMLITH_RULES}