Responses background mode doesn't work with external MCPs

API Bugs
1

I have a Responses configuration, that has two MCP servers – Slack and Gmail.

When I run it with background: true, it gets forever stuck in "status": "in_progress".
The only output I see is

"output": [
        {
            "id": "mcpl_68541983e64c8199873505a425805edb069b91f51c8e3f2d",
            "type": "mcp_list_tools",
            "server_label": "slack",
            "tools": []
        },
        {
            "id": "mcpl_68541983e67c8199a76794edf5ddc3b6069b91f51c8e3f2d",
            "type": "mcp_list_tools",
            "server_label": "gmail",
            "tools": []
        }
    ],

So I tried both stream and background stream: true, background: true and this at least ends in error:

event: error
data: {"type":"error","sequence_number":7,"error":{"message":"An error occurred while processing the request.","param":null,"type":"server_error","code":null}}

Then, when I run it without background: true, everything works as expected. I would really appreciate the background mode, but I’d have to hack it for now. It would be amazing if someone could look into this and fix it.

I kinda suspect the <redacted> in URL, isn’t it possible that it gets replaced in the config and then it doesn’t work in the background mode?

"tools": [
        {
            "type": "mcp",
            "allowed_tools": [
                "SLACK_ADD_REACTION_TO_AN_ITEM",
                "SLACK_CONVERSATIONS_HISTORY",
                "SLACK_FETCH_CONVERSATION_HISTORY",
                "SLACK_FETCH_ITEM_REACTIONS",
                "SLACK_SEARCH_MESSAGES",
                "SLACK_SENDS_A_MESSAGE_TO_A_SLACK_CHANNEL",
                "SLACK_USERS_LIST"
            ],
            "headers": null,
            "require_approval": "never",
            "server_label": "slack",
            "server_url": "https://mcp.composio.dev/<redacted>"
        },
        {
            "type": "mcp",
            "allowed_tools": [
                "GMAIL_ADD_LABEL_TO_EMAIL",
                "GMAIL_CREATE_EMAIL_DRAFT",
                "GMAIL_CREATE_LABEL",
                "GMAIL_DELETE_DRAFT",
                "GMAIL_DELETE_MESSAGE",
                "GMAIL_FETCH_EMAILS",
                "GMAIL_FETCH_MESSAGE_BY_MESSAGE_ID",
                "GMAIL_FETCH_MESSAGE_BY_THREAD_ID",
                "GMAIL_GET_ATTACHMENT",
                "GMAIL_GET_CONTACTS",
                "GMAIL_GET_PEOPLE",
                "GMAIL_GET_PROFILE",
                "GMAIL_LIST_DRAFTS",
                "GMAIL_LIST_LABELS",
                "GMAIL_LIST_THREADS",
                "GMAIL_MODIFY_THREAD_LABELS",
                "GMAIL_MOVE_TO_TRASH",
                "GMAIL_REMOVE_LABEL",
                "GMAIL_REPLY_TO_THREAD",
                "GMAIL_SEARCH_PEOPLE",
                "GMAIL_SEND_EMAIL"
            ],
            "headers": null,
            "require_approval": "never",
            "server_label": "gmail",
            "server_url": "https://mcp.composio.dev/<redacted>"
        }
    ],