sprut

sprut

sprut is an MCP Gateway. You list your MCP servers once, in one Config file, and give each AI Agent (Claude Code, Codex, Cursor, …) a single MCP server entry: sprut serve. Every Agent then sees all of your MCP servers' tools.

• One Config in the mcpServers JSON shape that MCP READMEs already show, so you can paste their snippets unchanged.
• Tools are exposed as <upstream>__<tool>, so tools from different Upstreams never collide.
• An Upstream that fails to start is skipped with a log line; the rest keep working.
• stdio and Streamable HTTP Upstreams. Legacy and modern (2026-07-28) MCP Agents and Upstreams work in any combination.
• One static binary. Each Agent runs its own sprut serve over stdio, with no daemon.

Install

From source (Go 1.27 or later):

go install github.com/marvell/sprut@latest

Or download a prebuilt binary for linux or darwin (amd64, arm64) from GitHub Releases and put sprut on your PATH.

Check it:

sprut --version

Config

sprut reads the first of these that is set:

1. sprut serve -c PATH (or --config PATH);
2. $SPRUT_CONFIG;
3. $XDG_CONFIG_HOME/sprut/config.json;
4. ~/.config/sprut/config.json.

{
  "mcpServers": {
    "memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    },
    "github": {
      "url": "https://api.githubcopilot.com/mcp/",
      "headers": { "Authorization": "Bearer ${GITHUB_TOKEN}" }
    },
    "postgres": {
      "command": "uvx",
      "args": ["postgres-mcp"],
      "env": { "DATABASE_URI": "${DATABASE_URI}" },
      "disabled": true
    }
  }
}

Each key under mcpServers names an Upstream. It must match ^[a-z0-9-]+$, and it becomes the prefix of that Upstream's tools (memory__read_graph).

${VAR} in args, env, url and headers is replaced from sprut's environment, so secrets stay out of the file. If a variable is unset, sprut skips that Upstream with a warning instead of substituting an empty string. Any other field is ignored with a warning.

Add sprut to your Agents

Each Agent runs sprut serve as a stdio MCP server. To give one Agent a different set of Upstreams, add -c PATH to its args.

Claude Code

claude mcp add --scope user sprut -- sprut serve

Codex (~/.codex/config.toml)

[mcp_servers.sprut]
command = "sprut"
args = ["serve"]

Cursor (~/.cursor/mcp.json), Gemini CLI (~/.gemini/settings.json), Claude Desktop (claude_desktop_config.json), and others using the same shape:

{
  "mcpServers": {
    "sprut": {
      "command": "sprut",
      "args": ["serve"]
    }
  }
}

VS Code (.vscode/mcp.json)

{
  "servers": {
    "sprut": {
      "type": "stdio",
      "command": "sprut",
      "args": ["serve"]
    }
  }
}

If the Agent does not find sprut on its PATH, use the binary's absolute path as the command.

Check your Config

--dry-run starts every Upstream exactly as a real run would and logs the same lines, then shuts them down. It exits 0 if every enabled Upstream started, and 1 if any failed:

$ sprut serve --dry-run
time=... level=WARN msg="unset variable GITHUB_TOKEN; upstream skipped" upstream=github
time=... level=INFO msg="upstream ready" upstream=memory tools=9 protocol=2025-06-18 duration=812ms
time=... level=INFO msg="gateway started" ready=1 failed=0 tools=9

Logs always go to stderr in logfmt, and stdout carries only MCP traffic. -v adds DEBUG lines: every Namespaced tool and every tool call. Each Upstream gets --startup-timeout (default 30s) to start.

Exit codes

License

MIT