fix(mcp): fail fast for noninteractive oauth without tokens

tests/hermes_cli/test_mcp_config.py

@@ -11,6 +11,14 @@ from pathlib import Path
 import pytest
 
 
+def _set_interactive_stdin(monkeypatch, *, is_tty: bool = True) -> None:
+    from unittest.mock import MagicMock
+
+    mock_stdin = MagicMock()
+    mock_stdin.isatty.return_value = is_tty
+    monkeypatch.setattr("tools.mcp_oauth.sys.stdin", mock_stdin)
+
+
 # ---------------------------------------------------------------------------
 # Fixtures
 # ---------------------------------------------------------------------------
@@ -649,6 +657,7 @@ class TestMcpRemoveEvictsManager:
             "hermes_cli.mcp_config.get_hermes_home", lambda: tmp_path
         )
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        _set_interactive_stdin(monkeypatch)
 
         from tools.mcp_oauth_manager import get_manager, reset_manager_for_tests
         reset_manager_for_tests()
@@ -745,4 +754,3 @@ class TestMcpLogin:
 
         assert "Authenticated — 3 tool(s) available" in out
         assert "no OAuth token" not in out
-

tests/tools/test_mcp_oauth.py

@@ -26,6 +26,12 @@ from tools.mcp_oauth import (
 )
 
 
+def _set_interactive_stdin(monkeypatch, *, is_tty: bool = True) -> None:
+    mock_stdin = MagicMock()
+    mock_stdin.isatty.return_value = is_tty
+    monkeypatch.setattr("tools.mcp_oauth.sys.stdin", mock_stdin)
+
+
 # ---------------------------------------------------------------------------
 # HermesTokenStorage
 # ---------------------------------------------------------------------------
@@ -164,6 +170,7 @@ class TestBuildOAuthAuth:
             pytest.skip("MCP SDK auth not available")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        _set_interactive_stdin(monkeypatch)
         auth = build_oauth_auth("test", "https://example.com/mcp")
         assert isinstance(auth, OAuthClientProvider)
 
@@ -180,6 +187,7 @@ class TestBuildOAuthAuth:
             pytest.skip("MCP SDK auth not available")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        _set_interactive_stdin(monkeypatch)
         build_oauth_auth("slack", "https://slack.example.com/mcp", {
             "client_id": "my-app-id",
             "client_secret": "my-secret",
@@ -199,6 +207,7 @@ class TestBuildOAuthAuth:
             pytest.skip("MCP SDK auth not available")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        _set_interactive_stdin(monkeypatch)
         provider = build_oauth_auth("scoped", "https://example.com/mcp", {
             "scope": "read write admin",
         })
@@ -403,6 +412,7 @@ class TestOAuthPortSharing:
             pytest.skip("MCP SDK auth not available")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        _set_interactive_stdin(monkeypatch)
         build_oauth_auth("test-port", "https://example.com/mcp")
         assert mod._oauth_port is not None
         assert isinstance(mod._oauth_port, int)
@@ -479,32 +489,21 @@ class TestWaitForCallbackNoBlocking:
 class TestBuildOAuthAuthNonInteractive:
     """build_oauth_auth() in non-interactive mode."""
 
-    def test_noninteractive_without_cached_tokens_warns(self, tmp_path, monkeypatch, caplog):
-        """Without cached tokens, non-interactive mode logs a clear warning."""
-        try:
-            from mcp.client.auth import OAuthClientProvider
-        except ImportError:
-            pytest.skip("MCP SDK auth not available")
+    def test_noninteractive_without_cached_tokens_fails_fast(self, tmp_path, monkeypatch):
+        """Without cached tokens, non-interactive mode skips browser auth."""
+        pytest.importorskip("mcp.client.auth")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
         mock_stdin = MagicMock()
         mock_stdin.isatty.return_value = False
         monkeypatch.setattr("tools.mcp_oauth.sys.stdin", mock_stdin)
 
-        import logging
-        with caplog.at_level(logging.WARNING, logger="tools.mcp_oauth"):
-            auth = build_oauth_auth("atlassian", "https://mcp.atlassian.com/v1/mcp")
-
-        assert auth is not None
-        assert "no cached tokens found" in caplog.text.lower()
-        assert "non-interactive" in caplog.text.lower()
+        with pytest.raises(OAuthNonInteractiveError, match="non-interactive"):
+            build_oauth_auth("atlassian", "https://mcp.atlassian.com/v1/mcp")
 
     def test_noninteractive_with_cached_tokens_no_warning(self, tmp_path, monkeypatch, caplog):
         """With cached tokens, non-interactive mode logs no 'no cached tokens' warning."""
-        try:
-            from mcp.client.auth import OAuthClientProvider
-        except ImportError:
-            pytest.skip("MCP SDK auth not available")
+        pytest.importorskip("mcp.client.auth")
 
         monkeypatch.setenv("HERMES_HOME", str(tmp_path))
         mock_stdin = MagicMock()

tests/tools/test_mcp_oauth_integration.py

@@ -18,6 +18,14 @@ import pytest
 pytest.importorskip("mcp.client.auth.oauth2", reason="MCP SDK 1.26.0+ required")
 
 
+def _set_interactive_stdin(monkeypatch, *, is_tty: bool = True) -> None:
+    from unittest.mock import MagicMock
+
+    mock_stdin = MagicMock()
+    mock_stdin.isatty.return_value = is_tty
+    monkeypatch.setattr("tools.mcp_oauth.sys.stdin", mock_stdin)
+
+
 @pytest.mark.asyncio
 async def test_external_refresh_picked_up_without_restart(tmp_path, monkeypatch):
     """Simulate Cthulhu's cron workflow end-to-end.
@@ -160,6 +168,7 @@ async def test_handle_401_returns_false_when_no_provider(tmp_path, monkeypatch):
 async def test_invalidate_if_disk_changed_handles_missing_file(tmp_path, monkeypatch):
     """invalidate_if_disk_changed returns False when tokens file doesn't exist."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
     from tools.mcp_oauth_manager import MCPOAuthManager, reset_manager_for_tests
     reset_manager_for_tests()
 
@@ -181,6 +190,7 @@ async def test_provider_is_reused_across_reconnects(tmp_path, monkeypatch):
     first post-reconnect auth flow would spuriously "detect" a change.
     """
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
     from tools.mcp_oauth_manager import MCPOAuthManager, reset_manager_for_tests
     reset_manager_for_tests()
 

tests/tools/test_mcp_oauth_manager.py

@@ -7,6 +7,7 @@ cache. See `tools/mcp_oauth_manager.py` for design rationale.
 import json
 import os
 import time
+from unittest.mock import MagicMock
 
 import pytest
 
@@ -16,6 +17,12 @@ pytest.importorskip(
 )
 
 
+def _set_interactive_stdin(monkeypatch, *, is_tty: bool = True) -> None:
+    mock_stdin = MagicMock()
+    mock_stdin.isatty.return_value = is_tty
+    monkeypatch.setattr("tools.mcp_oauth.sys.stdin", mock_stdin)
+
+
 def test_manager_is_singleton():
     """get_manager() returns the same instance across calls."""
     from tools.mcp_oauth_manager import get_manager, reset_manager_for_tests
@@ -28,6 +35,7 @@ def test_manager_is_singleton():
 def test_manager_get_or_build_provider_caches(tmp_path, monkeypatch):
     """Calling get_or_build_provider twice with same name returns same provider."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
     from tools.mcp_oauth_manager import MCPOAuthManager
 
     mgr = MCPOAuthManager()
@@ -39,6 +47,7 @@ def test_manager_get_or_build_provider_caches(tmp_path, monkeypatch):
 def test_manager_get_or_build_rebuilds_on_url_change(tmp_path, monkeypatch):
     """Changing the URL discards the cached provider."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
     from tools.mcp_oauth_manager import MCPOAuthManager
 
     mgr = MCPOAuthManager()
@@ -50,6 +59,7 @@ def test_manager_get_or_build_rebuilds_on_url_change(tmp_path, monkeypatch):
 def test_manager_remove_evicts_cache(tmp_path, monkeypatch):
     """remove(name) evicts the provider from cache AND deletes disk files."""
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
     from tools.mcp_oauth_manager import MCPOAuthManager
 
     # Pre-seed tokens on disk
@@ -131,6 +141,7 @@ def test_manager_builds_hermes_provider_subclass(tmp_path, monkeypatch):
     )
     reset_manager_for_tests()
     monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch)
 
     mgr = MCPOAuthManager()
     provider = mgr.get_or_build_provider("srv", "https://example.com/mcp", None)
@@ -139,3 +150,17 @@ def test_manager_builds_hermes_provider_subclass(tmp_path, monkeypatch):
     assert isinstance(provider, _HERMES_PROVIDER_CLS)
     assert provider._hermes_server_name == "srv"
 
+
+def test_manager_fails_fast_noninteractive_without_cached_tokens(tmp_path, monkeypatch):
+    """A daemon without cached MCP OAuth tokens must not enter browser auth."""
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    _set_interactive_stdin(monkeypatch, is_tty=False)
+    from tools.mcp_oauth import OAuthNonInteractiveError
+    from tools.mcp_oauth_manager import MCPOAuthManager
+
+    mgr = MCPOAuthManager()
+
+    with pytest.raises(OAuthNonInteractiveError, match="non-interactive"):
+        mgr.get_or_build_provider("linear", "https://mcp.linear.app/mcp", None)
+
+    assert mgr._entries["linear"].provider is None

tools/mcp_oauth.py

@@ -754,12 +754,12 @@ def build_oauth_auth(
     storage = HermesTokenStorage(server_name)
 
     if not _is_interactive() and not storage.has_cached_tokens():
-        logger.warning(
-            "MCP OAuth for '%s': non-interactive environment and no cached tokens "
+        raise OAuthNonInteractiveError(
+            "MCP OAuth for "
+            f"'{server_name}': non-interactive environment and no cached tokens "
             "found. The OAuth flow requires browser authorization. Run "
-            "interactively first to complete the initial authorization, then "
-            "cached tokens will be reused.",
-            server_name,
+            f"`hermes mcp login {server_name}` interactively first to complete "
+            "initial authorization, then cached tokens will be reused."
         )
 
     _configure_callback_port(cfg)

tools/mcp_oauth_manager.py

@@ -408,6 +408,7 @@ class MCPOAuthManager:
         # Local imports avoid circular deps at module import time.
         from tools.mcp_oauth import (
             HermesTokenStorage,
+            OAuthNonInteractiveError,
             _OAUTH_AVAILABLE,
             _build_client_metadata,
             _configure_callback_port,
@@ -424,11 +425,12 @@ class MCPOAuthManager:
         storage = HermesTokenStorage(server_name)
 
         if not _is_interactive() and not storage.has_cached_tokens():
-            logger.warning(
-                "MCP OAuth for '%s': non-interactive environment and no "
-                "cached tokens found. Run interactively first to complete "
-                "initial authorization.",
-                server_name,
+            raise OAuthNonInteractiveError(
+                "MCP OAuth for "
+                f"'{server_name}': non-interactive environment and no "
+                "cached tokens found. Run `hermes mcp login "
+                f"{server_name}` interactively first to complete initial "
+                "authorization."
             )
 
         _configure_callback_port(cfg)