feat(MCP): add RedisVL MCP CLI

redisvl/cli/main.py

@@ -14,6 +14,7 @@ def _usage():
         "rvl <command> [<args>]\n",
         "Commands:",
         "\tindex       Index manipulation (create, delete, etc.)",
+        "\tmcp         Run the RedisVL MCP server",
         "\tversion     Obtain the version of RedisVL",
         "\tstats       Obtain statistics about an index",
     ]
@@ -42,6 +43,12 @@ def index(self):
         Index()
         exit(0)
 
+    def mcp(self):
+        from redisvl.cli.mcp import MCP
+
+        MCP()
+        exit(0)
+
     def version(self):
         Version()
         exit(0)

redisvl/cli/mcp.py

@@ -0,0 +1,136 @@
+"""CLI entrypoint for the RedisVL MCP server."""
+
+import argparse
+import asyncio
+import inspect
+import sys
+
+
+class _MCPArgumentParser(argparse.ArgumentParser):
+    """ArgumentParser variant that reports usage errors with exit code 1."""
+
+    def error(self, message):
+        self.print_usage(sys.stderr)
+        self.exit(1, "%s: error: %s\n" % (self.prog, message))
+
+
+class MCP:
+    """Command handler for `rvl mcp`."""
+
+    description = "Expose a configured Redis index to MCP clients for search and optional upsert operations."
+    epilog = (
+        "Use this command when wiring RedisVL into an MCP client.\n\n"
+        "Example:\n"
+        "  uvx --from redisvl[mcp] rvl mcp --config /path/to/mcp_config.yaml"
+    )
+    usage = "\n".join(
+        [
+            "rvl mcp --config <path> [--read-only]\n",
+            "\n",
+        ]
+    )
+
+    def __init__(self):
+        """Parse CLI arguments and run the MCP server command."""
+        parser = _MCPArgumentParser(
+            usage=self.usage,
+            description=self.description,
+            epilog=self.epilog,
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+        )
+        parser.add_argument("--config", help="Path to MCP config file", required=True)
+        parser.add_argument(
+            "--read-only",
+            help="Disable the upsert tool",
+            action="store_true",
+            dest="read_only",
+            default=None,
+        )
+
+        args = parser.parse_args(sys.argv[2:])
+        self._run(args)
+        raise SystemExit(0)
+
+    def _run(self, args):
+        """Validate the environment, build the server, and serve stdio requests."""
+        try:
+            self._ensure_supported_python()
+            settings_cls, server_cls = self._load_mcp_components()
+            settings = settings_cls.from_env(
+                config=args.config,
+                read_only=args.read_only,
+            )
+            server = server_cls(settings)
+            self._run_awaitable(self._serve(server))
+        except KeyboardInterrupt:
+            raise SystemExit(0)
+        except Exception as exc:
+            self._print_error(str(exc))
+            raise SystemExit(1)
+
+    @staticmethod
+    def _ensure_supported_python():
+        """Fail fast when the current interpreter cannot support MCP extras."""
+        if sys.version_info < (3, 10):
+            version = "%s.%s.%s" % (
+                sys.version_info.major,
+                sys.version_info.minor,
+                sys.version_info.micro,
+            )
+            raise RuntimeError(
+                "RedisVL MCP CLI requires Python 3.10 or newer. "
+                "Current runtime is Python %s." % version
+            )
+
+    @staticmethod
+    def _load_mcp_components():
+        """Import optional MCP dependencies only on the `rvl mcp` code path."""
+        try:
+            from redisvl.mcp import MCPSettings, RedisVLMCPServer
+        except (ImportError, ModuleNotFoundError) as exc:
+            raise RuntimeError(
+                "RedisVL MCP support requires optional dependencies. "
+                "Install them with `pip install redisvl[mcp]`.\n"
+                "Original error: %s" % exc
+            )
+
+        return MCPSettings, RedisVLMCPServer
+
+    @staticmethod
+    def _run_awaitable(awaitable):
+        """Bridge the synchronous CLI entrypoint to async server lifecycle code."""
+        return asyncio.run(awaitable)
+
+    async def _serve(self, server):
+        """Run startup, stdio serving, and shutdown on one event loop."""
+        started = False
+
+        try:
+            await server.startup()
+            started = True
+
+            # Prefer FastMCP's async transport path so startup, serving, and
+            # shutdown all share the same event loop.
+            run_async = getattr(server, "run_async", None)
+            if callable(run_async):
+                await run_async(transport="stdio")
+            else:
+                result = server.run(transport="stdio")
+                if inspect.isawaitable(result):
+                    await result
+        finally:
+            if started:
+                try:
+                    result = server.shutdown()
+                    if inspect.isawaitable(result):
+                        await result
+                except RuntimeError as exc:
+                    # KeyboardInterrupt during stdio shutdown can leave FastMCP
+                    # tearing down after the loop is already closing.
+                    if "Event loop is closed" not in str(exc):
+                        raise
+
+    @staticmethod
+    def _print_error(message):
+        """Emit user-facing command errors to stderr."""
+        print(message, file=sys.stderr)