fix(mcp): default Slack registry entry to streamable HTTP with OAuth

Slack offers a hosted MCP server at https://mcp.slack.com/mcp over
streamable HTTP with OAuth, so the curated discovery preset should point
there instead of spawning the npx stdio bot-token server. Carry an
auth_type through the discovery entry into the create-server form so the
preset lands on OAuth by default.

litellm/proxy/mcp_registry.json

@@ -69,13 +69,10 @@
       "icon_url": "https://cdn.simpleicons.org/slack",
       "category": "Communication",
       "registry_url": null,
-      "transport": "stdio",
-      "command": "npx",
-      "args": ["-y", "@modelcontextprotocol/server-slack"],
-      "env_vars": [
-        {"name": "SLACK_BOT_TOKEN", "description": "Slack Bot User OAuth Token", "secret": true},
-        {"name": "SLACK_TEAM_ID", "description": "Slack Team/Workspace ID", "secret": false}
-      ]
+      "transport": "http",
+      "url": "https://mcp.slack.com/mcp",
+      "auth_type": "oauth2",
+      "env_vars": []
     },
     {
       "name": "discord",

tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_discovery.py

@@ -94,6 +94,17 @@ class TestMCPRegistryFile:
         assert linear["url"] == "https://mcp.linear.app/mcp"
         assert "/sse" not in linear["url"]
 
+    def test_slack_defaults_to_streamable_http_oauth(self, registry_path):
+        """Slack's MCP server should default to streamable HTTP with the hosted /mcp endpoint and OAuth."""
+        with open(registry_path, "r") as f:
+            data = json.load(f)
+        slack = next(s for s in data["servers"] if s["name"] == "slack")
+        assert slack["transport"] == "http"
+        assert slack["url"] == "https://mcp.slack.com/mcp"
+        assert slack["auth_type"] == "oauth2"
+        assert "command" not in slack
+        assert "args" not in slack
+
     def test_well_known_servers_present(self, registry_path):
         """Ensure key well-known MCPs are in the registry."""
         with open(registry_path, "r") as f:

ui/litellm-dashboard/src/components/mcp_tools/create_mcp_server.test.tsx

@@ -754,6 +754,30 @@ describe("CreateMCPServer", () => {
         expect(nameInput).toHaveValue("github_mcp");
       });
     });
+
+    it("prefills streamable HTTP, URL, and OAuth from a discovery preset like Slack", async () => {
+      const prefillData = {
+        name: "slack",
+        title: "Slack",
+        description: "Channel management, messaging, and Slack workspace integration",
+        category: "Communication",
+        transport: "http",
+        url: "https://mcp.slack.com/mcp",
+        auth_type: "oauth2",
+      };
+
+      render(<CreateMCPServer {...defaultProps} prefillData={prefillData} />);
+
+      await waitFor(() => {
+        const urlInput = screen.getByPlaceholderText("https://your-mcp-server.com");
+        expect(urlInput).toHaveValue("https://mcp.slack.com/mcp");
+      });
+
+      // Setting auth_type to oauth2 should render the OAuth form fields
+      await waitFor(() => {
+        expect(screen.getByText("OAuth Flow Type")).toBeInTheDocument();
+      });
+    });
   });
 
   describe("with back to discovery button", () => {

ui/litellm-dashboard/src/components/mcp_tools/create_mcp_server.tsx

@@ -273,6 +273,10 @@ const CreateMCPServer: React.FC<CreateMCPServerProps> = ({
       transport: transport,
     };
 
+    if (prefillData.auth_type) {
+      prefillValues.auth_type = prefillData.auth_type;
+    }
+
     if (transport === "stdio") {
       const stdioObj: Record<string, any> = {};
       if (prefillData.command) stdioObj.command = prefillData.command;

ui/litellm-dashboard/src/components/mcp_tools/types.tsx

@@ -332,6 +332,7 @@ export interface DiscoverableMCPServer {
   url?: string | null;
   command?: string | null;
   args?: string[] | null;
+  auth_type?: string | null;
   env_vars?: Array<{ name: string; description?: string; secret?: boolean }> | null;
 }