[eric] tests: the discover gate refuses tokenless env_vars servers at the route level, spawn provably untouched

backend/tests/test_tools_discover_gate.py

@@ -0,0 +1,63 @@
+"""Discovery must refuse to spawn a credential-driven MCP server that has no credentials yet.
+
+The Slack case: a tokenless `npx slack-mcp-server` dies at boot and the npm wrapper buries the one
+useful line under a Node crash dump, which is exactly the toast users saw. The right answer is a
+clean 409 before any spawn, and an untouched spawn path once credentials exist.
+"""
+
+from __future__ import annotations
+
+import pytest
+from unittest.mock import patch
+from fastapi.testclient import TestClient
+
+from backend.main import app
+
+
+@pytest.fixture
+def client():
+    import backend.auth as auth_mod
+    if not auth_mod.TOKEN:
+        import secrets
+        auth_mod.TOKEN = secrets.token_urlsafe(32)
+    return TestClient(app, headers={"Authorization": f"Bearer {auth_mod.TOKEN}"})
+
+
+def p_create_tool(client: TestClient, credentials: dict) -> str:
+    res = client.post("/api/tools/create", json={
+        "name": "SlackGateTest",
+        "description": "gate test",
+        "command": "",
+        "mcp_config": {"type": "stdio", "command": "npx", "args": ["-y", "slack-mcp-server@1.3.0", "--transport", "stdio"]},
+        "credentials": credentials,
+        "auth_type": "env_vars",
+        "auth_status": "configured",
+    })
+    assert res.status_code == 200
+    return res.json()["tool"]["id"]
+
+
+def test_credentialless_env_vars_tool_gets_409_and_no_spawn(client):
+    tool_id = p_create_tool(client, credentials={})
+    try:
+        with patch("backend.apps.tools_lib.tools_lib.discover_mcp_tools_stdio") as spawn:
+            res = client.post(f"/api/tools/{tool_id}/discover")
+        assert res.status_code == 409
+        assert "Connect" in res.json()["detail"]
+        spawn.assert_not_called()
+    finally:
+        client.delete(f"/api/tools/{tool_id}")
+
+
+def test_credentialed_tool_still_reaches_the_spawn_path(client):
+    tool_id = p_create_tool(client, credentials={"SLACK_MCP_XOXC_TOKEN": "xoxc-test", "SLACK_MCP_XOXD_TOKEN": "xoxd-test"})
+    try:
+        async def p_fake_discover(**kwargs):
+            assert kwargs["env"]["SLACK_MCP_XOXC_TOKEN"] == "xoxc-test"
+            return [{"name": "channels_list", "description": "", "inputSchema": None}]
+        with patch("backend.apps.tools_lib.tools_lib.discover_mcp_tools_stdio", side_effect=p_fake_discover):
+            res = client.post(f"/api/tools/{tool_id}/discover")
+        assert res.status_code == 200
+        assert "channels_list" in res.json()["tool"]["tool_permissions"]
+    finally:
+        client.delete(f"/api/tools/{tool_id}")