perf(mcp): optimize test performance with parallel connections and reduced retries

- Connect to MCP servers concurrently instead of sequentially
- Reduce retry settings in test mode (IS_TEST=True):
  - 1 attempt instead of 3
  - 100ms retry delay instead of 1s
  - 2s timeout instead of 30-120s

Reduces MCP E2E test time from ~16s to under 1s.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/services/mcp/client_manager.py

@@ -122,16 +122,24 @@ class MCPClientManager:
             )
 
     async def _connect_all_servers(self) -> None:
-        """Connect to all enabled MCP servers."""
+        """Connect to all enabled MCP servers concurrently."""
+        import asyncio
+
         enabled_servers = self._registry.get_enabled_configs()
 
-        for name, config in enabled_servers.items():
+        async def connect_server(name: str, config: "MCPServerConfig") -> None:
             try:
                 await self._pool.get_connection(name, config)
                 logger.info("Connected to MCP server: %s", name)
             except Exception as e:
                 logger.error("Failed to connect to MCP server %s: %s", name, e)
 
+        # Connect to all servers concurrently for faster startup
+        await asyncio.gather(
+            *(connect_server(name, config) for name, config in enabled_servers.items()),
+            return_exceptions=True,
+        )
+
     async def shutdown(self) -> None:
         """
         Shutdown the MCP client manager.

backend/app/services/mcp/config.py

@@ -179,6 +179,8 @@ def load_mcp_config(path: str | Path | None = None) -> MCPConfig:
     2. MCP_CONFIG_PATH environment variable
     3. Default path (backend/mcp_servers.yaml)
     4. Empty config if no file exists
+
+    In test mode (IS_TEST=True), retry settings are reduced for faster tests.
     """
     if path is None:
         path = os.environ.get("MCP_CONFIG_PATH", str(DEFAULT_CONFIG_PATH))
@@ -189,7 +191,18 @@ def load_mcp_config(path: str | Path | None = None) -> MCPConfig:
         # Return empty config if no file exists (allows runtime registration)
         return MCPConfig()
 
-    return MCPConfig.from_yaml(path)
+    config = MCPConfig.from_yaml(path)
+
+    # In test mode, reduce retry settings to speed up tests
+    is_test = os.environ.get("IS_TEST", "").lower() in ("true", "1", "yes")
+    if is_test:
+        for server_config in config.mcp_servers.values():
+            server_config.retry_attempts = 1  # Single attempt
+            server_config.retry_delay = 0.1  # 100ms instead of 1s
+            server_config.retry_max_delay = 0.5  # 500ms max
+            server_config.timeout = 2  # 2s timeout instead of 30-120s
+
+    return config
 
 
 def create_default_config() -> MCPConfig: