diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 9c29927c5cb..7f8b94d0b8f 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -13399,3 +13399,23 @@ async def dynamic_mcp_route(mcp_server_name: str, request: Request):
 app.mount(path=BASE_MCP_ROUTE, app=mcp_app)
 app.include_router(mcp_rest_endpoints_router)
 app.include_router(mcp_discoverable_endpoints_router)
+
+
+# Rewrite /mcp -> /mcp/ internally to avoid 307 redirect from Starlette's
+# mounted sub-application routing.  Many MCP clients (e.g. Claude Code) send
+# POST /mcp and do not follow redirects for POST, which drops the request body.
+# Using a pure ASGI middleware (not BaseHTTPMiddleware) keeps SSE streaming intact.
+class _MCPTrailingSlashMiddleware:
+    """Transparently append '/' to the MCP mount path so Starlette serves it
+    directly instead of responding with 307 Temporary Redirect."""
+
+    def __init__(self, app: Any) -> None:  # noqa: F811
+        self.app = app
+
+    async def __call__(self, scope: Any, receive: Any, send: Any) -> None:
+        if scope["type"] == "http" and scope.get("path") == BASE_MCP_ROUTE:
+            scope = dict(scope, path=BASE_MCP_ROUTE + "/")
+        await self.app(scope, receive, send)
+
+
+app.add_middleware(_MCPTrailingSlashMiddleware)