init commit

agents/shared/mcp_client.py

@@ -0,0 +1,137 @@
+"""Multi-server MCP client using fastmcp composition.
+
+Composes the three domain-scoped MCP servers into namespaced configurations
+that agents connect to as a single client.
+"""
+
+import json
+from contextlib import asynccontextmanager
+from typing import Any
+
+from fastmcp import Client
+
+
+# Server configurations for stdio transport
+SERVERS = {
+    "shared": {
+        "command": "uv",
+        "args": ["run", "python", "-m", "mcp_servers.shared"],
+    },
+    "ops": {
+        "command": "uv",
+        "args": ["run", "python", "-m", "mcp_servers.ops"],
+    },
+    "passenger": {
+        "command": "uv",
+        "args": ["run", "python", "-m", "mcp_servers.passenger"],
+    },
+}
+
+# Agent profiles — which servers each agent connects to
+AGENT_PROFILES = {
+    "efhas": ["shared", "ops", "passenger"],
+    "handover": ["shared", "ops"],
+}
+
+
+class MCPMultiClient:
+    """Manages connections to multiple MCP servers via fastmcp Client."""
+
+    def __init__(self) -> None:
+        self._clients: dict[str, Client] = {}
+
+    async def connect(self, server_names: list[str]) -> None:
+        """Connect to the specified MCP servers."""
+        for name in server_names:
+            if name not in SERVERS:
+                raise ValueError(f"Unknown server: {name}. Available: {list(SERVERS.keys())}")
+            config = {"mcpServers": {"default": SERVERS[name]}}
+            client = Client(config)
+            await client.__aenter__()
+            self._clients[name] = client
+
+    async def close(self) -> None:
+        """Close all server connections."""
+        for client in self._clients.values():
+            try:
+                await client.__aexit__(None, None, None)
+            except (Exception, BaseException):
+                pass
+        self._clients.clear()
+
+    async def call_tool(self, server: str, tool_name: str, arguments: dict) -> Any:
+        """Call a tool on a specific server. Returns parsed result."""
+        client = self._clients.get(server)
+        if not client:
+            raise ValueError(f"Not connected to server: {server}")
+
+        result = await client.call_tool(tool_name, arguments)
+
+        # Parse the result content
+        if isinstance(result, list):
+            texts = [c.text for c in result if hasattr(c, "text")]
+        elif hasattr(result, "content"):
+            texts = [c.text for c in result.content if hasattr(c, "text")]
+        else:
+            return result
+
+        if len(texts) == 1:
+            try:
+                return json.loads(texts[0])
+            except (json.JSONDecodeError, TypeError):
+                return texts[0]
+        elif len(texts) > 1:
+            parsed = []
+            for t in texts:
+                try:
+                    parsed.append(json.loads(t))
+                except (json.JSONDecodeError, TypeError):
+                    parsed.append(t)
+            return parsed
+        return None
+
+    async def read_resource(self, server: str, uri: str) -> Any:
+        """Read a resource from a specific server."""
+        client = self._clients.get(server)
+        if not client:
+            raise ValueError(f"Not connected to server: {server}")
+
+        result = await client.read_resource(uri)
+        if isinstance(result, str):
+            try:
+                return json.loads(result)
+            except (json.JSONDecodeError, TypeError):
+                return result
+        return result
+
+    async def get_prompt(self, server: str, prompt_name: str, arguments: dict) -> str:
+        """Get a rendered prompt from a specific server."""
+        client = self._clients.get(server)
+        if not client:
+            raise ValueError(f"Not connected to server: {server}")
+
+        result = await client.get_prompt(prompt_name, arguments)
+        if isinstance(result, str):
+            return result
+        # Handle structured prompt response
+        texts = []
+        if hasattr(result, "messages"):
+            for msg in result.messages:
+                if hasattr(msg.content, "text"):
+                    texts.append(msg.content.text)
+                elif isinstance(msg.content, list):
+                    for c in msg.content:
+                        if hasattr(c, "text"):
+                            texts.append(c.text)
+        return "\n".join(texts) if texts else str(result)
+
+
+@asynccontextmanager
+async def connect_servers(server_names: list[str]):
+    """Context manager for multi-server MCP connections."""
+    client = MCPMultiClient()
+    try:
+        await client.connect(server_names)
+        yield client
+    finally:
+        await client.close()