diff --git a/superset/mcp_service/composite_token_verifier.py b/superset/mcp_service/composite_token_verifier.py
new file mode 100644
index 00000000000..e4f5c6a5c43
--- /dev/null
+++ b/superset/mcp_service/composite_token_verifier.py
@@ -0,0 +1,80 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""
+Composite token verifier for MCP authentication.
+
+Routes Bearer tokens to the appropriate verifier based on prefix:
+- Tokens matching FAB_API_KEY_PREFIXES (e.g. ``sst_``) are passed through
+  to the Flask layer where ``_resolve_user_from_api_key()`` handles
+  actual validation via FAB SecurityManager.
+- All other tokens are delegated to the wrapped JWT verifier.
+"""
+
+import logging
+
+from fastmcp.server.auth import AccessToken
+from fastmcp.server.auth.providers.jwt import TokenVerifier
+
+logger = logging.getLogger(__name__)
+
+
+class CompositeTokenVerifier(TokenVerifier):
+    """Routes Bearer tokens between API key pass-through and JWT verification.
+
+    API key tokens (identified by prefix) are accepted at the transport layer
+    with a marker claim so that ``_resolve_user_from_jwt_context()`` can
+    detect them and fall through to ``_resolve_user_from_api_key()`` for
+    actual validation.
+
+    Args:
+        jwt_verifier: The wrapped JWT verifier for non-API-key tokens.
+        api_key_prefixes: List of prefixes that identify API key tokens
+            (e.g. ``["sst_"]``).
+    """
+
+    def __init__(
+        self,
+        jwt_verifier: TokenVerifier,
+        api_key_prefixes: list[str],
+    ) -> None:
+        super().__init__(
+            base_url=getattr(jwt_verifier, "base_url", None),
+            required_scopes=jwt_verifier.required_scopes,
+        )
+        self._jwt_verifier = jwt_verifier
+        self._api_key_prefixes = tuple(api_key_prefixes)
+
+    async def verify_token(self, token: str) -> AccessToken | None:
+        """Verify a Bearer token.
+
+        If the token starts with an API key prefix, return a pass-through
+        AccessToken with a ``_api_key_passthrough`` claim. The Flask-layer
+        ``_resolve_user_from_api_key()`` performs the real validation.
+
+        Otherwise, delegate to the wrapped JWT verifier.
+        """
+        if any(token.startswith(prefix) for prefix in self._api_key_prefixes):
+            logger.debug("API key token detected (prefix match), passing through")
+            return AccessToken(
+                token=token,
+                client_id="api_key",
+                scopes=[],
+                claims={"_api_key_passthrough": True},
+            )
+
+        return await self._jwt_verifier.verify_token(token)
diff --git a/tests/unit_tests/mcp_service/test_composite_token_verifier.py b/tests/unit_tests/mcp_service/test_composite_token_verifier.py
new file mode 100644
index 00000000000..537fe4d8f07
--- /dev/null
+++ b/tests/unit_tests/mcp_service/test_composite_token_verifier.py
@@ -0,0 +1,105 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Tests for CompositeTokenVerifier."""
+
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+from fastmcp.server.auth import AccessToken
+
+from superset.mcp_service.composite_token_verifier import CompositeTokenVerifier
+
+
+@pytest.fixture
+def mock_jwt_verifier():
+    verifier = MagicMock()
+    verifier.required_scopes = []
+    verifier.verify_token = AsyncMock()
+    return verifier
+
+
+@pytest.fixture
+def composite_verifier(mock_jwt_verifier):
+    return CompositeTokenVerifier(
+        jwt_verifier=mock_jwt_verifier,
+        api_key_prefixes=["sst_", "pat_"],
+    )
+
+
+@pytest.mark.asyncio
+async def test_api_key_token_returns_passthrough(composite_verifier) -> None:
+    """Tokens matching an API key prefix return a pass-through AccessToken."""
+    api_key = "sst_abc123secret"  # noqa: S105
+    result = await composite_verifier.verify_token(api_key)
+
+    assert result is not None
+    assert result.token == api_key
+    assert result.client_id == "api_key"
+    assert result.claims.get("_api_key_passthrough") is True
+
+
+@pytest.mark.asyncio
+async def test_second_prefix_matches(composite_verifier) -> None:
+    """All configured prefixes are checked, not just the first."""
+    result = await composite_verifier.verify_token("pat_mytoken")
+
+    assert result is not None
+    assert result.claims.get("_api_key_passthrough") is True
+
+
+@pytest.mark.asyncio
+async def test_jwt_token_delegates_to_wrapped_verifier(
+    composite_verifier, mock_jwt_verifier
+) -> None:
+    """Non-API-key tokens are delegated to the wrapped JWT verifier."""
+    jwt_token = "eyJhbGciOiJSUzI1NiJ9.jwt_payload"  # noqa: S105
+    jwt_result = AccessToken(
+        token=jwt_token,
+        client_id="oauth_client",
+        scopes=["read"],
+        claims={"sub": "user1"},
+    )
+    mock_jwt_verifier.verify_token.return_value = jwt_result
+
+    result = await composite_verifier.verify_token("eyJhbGciOiJSUzI1NiJ9.jwt_payload")
+
+    assert result is jwt_result
+    mock_jwt_verifier.verify_token.assert_awaited_once_with(
+        "eyJhbGciOiJSUzI1NiJ9.jwt_payload"
+    )
+
+
+@pytest.mark.asyncio
+async def test_invalid_jwt_returns_none(composite_verifier, mock_jwt_verifier) -> None:
+    """When the JWT verifier rejects a token, None is returned."""
+    mock_jwt_verifier.verify_token.return_value = None
+
+    result = await composite_verifier.verify_token("not_a_valid_token")
+
+    assert result is None
+    mock_jwt_verifier.verify_token.assert_awaited_once()
+
+
+@pytest.mark.asyncio
+async def test_api_key_does_not_call_jwt_verifier(
+    composite_verifier, mock_jwt_verifier
+) -> None:
+    """API key tokens bypass the JWT verifier entirely."""
+    await composite_verifier.verify_token("sst_test_key")
+
+    mock_jwt_verifier.verify_token.assert_not_awaited()