feat: add CORS middleware support for SSE and HTTP transports in MCP server

cognee-mcp/src/server.py

@@ -20,6 +20,9 @@ from cognee.modules.search.types import SearchType
 from cognee.shared.data_models import KnowledgeGraph
 from cognee.modules.storage.utils import JSONEncoder
 from starlette.responses import JSONResponse
+from starlette.middleware import Middleware
+from starlette.middleware.cors import CORSMiddleware
+import uvicorn
 
 
 try:
@@ -39,8 +42,59 @@ mcp = FastMCP("Cognee")
 logger = get_logger()
 
 
+cors_middleware = Middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
+    allow_headers=["*"],
+)
+
+
+async def run_sse_with_cors():
+    """Custom SSE transport with CORS middleware."""
+    sse_app = mcp.sse_app()
+    sse_app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
+        allow_headers=["*"],
+    )
+
+    config = uvicorn.Config(
+        sse_app,
+        host=mcp.settings.host,
+        port=mcp.settings.port,
+        log_level=mcp.settings.log_level.lower(),
+    )
+    server = uvicorn.Server(config)
+    await server.serve()
+
+
+async def run_http_with_cors():
+    """Custom HTTP transport with CORS middleware."""
+    http_app = mcp.streamable_http_app()
+    http_app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
+        allow_headers=["*"],
+    )
+
+    config = uvicorn.Config(
+        http_app,
+        host=mcp.settings.host,
+        port=mcp.settings.port,
+        log_level=mcp.settings.log_level.lower(),
+    )
+    server = uvicorn.Server(config)
+    await server.serve()
+
+
 @mcp.custom_route("/health", methods=["GET"])
-async def health_check(request) -> dict:
+async def health_check(request):
     return JSONResponse({"status": "ok"})
 
 
@@ -981,12 +1035,12 @@ async def main():
         await mcp.run_stdio_async()
     elif args.transport == "sse":
         logger.info(f"Running MCP server with SSE transport on {args.host}:{args.port}")
-        await mcp.run_sse_async()
+        await run_sse_with_cors()
     elif args.transport == "http":
         logger.info(
             f"Running MCP server with Streamable HTTP transport on {args.host}:{args.port}{args.path}"
         )
-        await mcp.run_streamable_http_async()
+        await run_http_with_cors()
 
 
 if __name__ == "__main__":