Restrict Gmail connections to an email domain

Accept a Gmail connection only when its mailbox address belongs to your allowed domain. This example connects an account, checks its address on the server, and prepares agent tools only after approval.

The check runs after Google authentication. It doesn't restrict Google's account picker or prove Google Workspace membership. For an organization-membership policy, follow Google's guidance on the validated hd claim.

Set up the project

Use Python 3.12 or Node.js 24.17 or newer. Install in a new project, using a virtual environment for Python:

uv add composio

Set a Composio project key and a fresh application user ID for this demo:

export COMPOSIO_API_KEY="your-composio-api-key"
export COMPOSIO_USER_ID="domain-check-demo"

In your application, derive the user ID from your authenticated session. Keep the API key and this code on the server. If you use a scoped project key, enable Proxy execute.

The script calls Gmail's users.getProfile endpoint with me, which selects the authenticated mailbox. It reads the returned emailAddress. The endpoint requires a Gmail scope such as https://www.googleapis.com/auth/gmail.readonly; openid and email alone don't grant this access. Ensure your Gmail auth config requests gmail.readonly if the agent will also read messages. See Controlling scopes to configure scopes and reconnect after changing them.

Connect and check the account

Replace example.com in the script with your allowed domain. Run the script, open the printed Connect Link, and complete authentication within five minutes. The script polls its own connection request, so it doesn't need an HTTP callback handler.

import os
from email.headerregistry import Address

from composio import Composio

ALLOWED_DOMAIN = "example.com"


def approved_email(data):
    email = data["emailAddress"]
    address = Address(addr_spec=email)
    if (
        not address.username
        or address.addr_spec != email
        or address.domain.lower() != ALLOWED_DOMAIN.lower()
    ):
        raise ValueError("Mailbox address is not allowed")
    return email


composio = Composio()
user_id = os.environ["COMPOSIO_USER_ID"]
onboarding = composio.create(
    user_id=user_id,
    toolkits=["gmail"],
    manage_connections=False,
    sandbox={"enable": False},
)
request = onboarding.authorize("gmail")
print(f"Connect Gmail: {request.redirect_url}", flush=True)

try:
    account = request.wait_for_connection(timeout=300)  # Python uses seconds.
    response = composio.tools.proxy(
        endpoint="https://gmail.googleapis.com/gmail/v1/users/me/profile",
        method="GET",
        connected_account_id=account.id,
    )
    if response["status"] != 200:
        raise RuntimeError("Gmail profile request failed")
    email = approved_email(response["data"])
except Exception:
    # Also reject missing identity, insufficient scopes, and timeouts.
    composio.connected_accounts.disable(request.id)
    raise SystemExit(
        f"Connection disabled. Rerun and connect a Gmail account at {ALLOWED_DOMAIN}. "
        "If you used that domain, check the Gmail scopes and try again."
    ) from None

session = composio.create(
    user_id=user_id,
    toolkits=["gmail"],
    connected_accounts={"gmail": [account.id]},
    manage_connections=False,
    sandbox={"enable": False},
)
tools = session.tools()
print(f"Connected as {email}. Agent tools are ready for this account.")

python restrict_gmail.py

For an approved account, the script prints Connected as alice@example.com. Agent tools are ready for this account. Pass the returned tools to your agent framework using this approved session. The default SDK provider returns OpenAI-compatible tools; configure your framework's provider when constructing Composio if needed.

For a rejected account, the script disables the connection and exits before creating the agent session. If disabling fails, the script stops with that error and still doesn't create the agent session. Resolve the failure before retrying. Disabling a connection blocks Composio tool execution; it doesn't revoke Google's OAuth grant.

Keep the check in the execution path

The onboarding session never supplies tools to an agent. The second session selects the approved account explicitly and disables in-chat connection management, so the agent can't connect another account through that session. Don't expose the onboarding session to clients or reuse other sessions that can select unchecked accounts. Apply the same validation whenever you accept a new or replacement connection.

The domain comparison ignores case and requires an exact match. alice@EXAMPLE.COM passes; alice@gmail.com, alice@sub.example.com, and alice@notexample.com don't. Missing or malformed profile data and failed profile requests also prevent approval. An alias such as work-gmail or the account's displayName isn't the input to this decision.

To display identity without a domain policy, see Identify the connected account. For session account selection, see Managing multiple connected accounts.