perf(mcp): persist list_tools discovery in connector.config.cached_tools

Skip the ~1-3s MCP initialize + list_tools handshake on every cache miss
by reading tool definitions from the connector row we already load. Lazy
populate on first miss, self-heal on corrupt cache, zero schema migration.

surfsense_backend/tests/unit/agents/new_chat/tools/test_mcp_tools_cache.py

@@ -0,0 +1,130 @@
+"""Unit tests for ``mcp_tools_cache``."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from types import SimpleNamespace
+
+import pytest
+
+from app.agents.new_chat.tools.mcp_tools_cache import (
+    CachedMCPToolDef,
+    CachedMCPTools,
+    read_cached_tools,
+)
+
+pytestmark = pytest.mark.unit
+
+
+def _make_connector(config: dict | None) -> SimpleNamespace:
+    return SimpleNamespace(id=42, config=config)
+
+
+def test_read_returns_none_when_config_is_none() -> None:
+    assert read_cached_tools(_make_connector(None)) is None
+
+
+def test_read_returns_none_when_cached_tools_missing() -> None:
+    assert read_cached_tools(_make_connector({"server_config": {}})) is None
+
+
+def test_read_returns_none_when_cached_tools_is_not_a_dict() -> None:
+    assert read_cached_tools(_make_connector({"cached_tools": []})) is None
+    assert read_cached_tools(_make_connector({"cached_tools": "stale"})) is None
+
+
+def test_read_parses_minimal_valid_payload() -> None:
+    parsed = read_cached_tools(
+        _make_connector(
+            {
+                "cached_tools": {
+                    "discovered_at": "2026-05-20T10:00:00+00:00",
+                    "tools": [
+                        {
+                            "name": "list_issues",
+                            "description": "List Linear issues",
+                            "input_schema": {"type": "object"},
+                        }
+                    ],
+                }
+            }
+        )
+    )
+    assert parsed is not None
+    assert parsed.server_version is None
+    assert parsed.server_name is None
+    assert parsed.transport is None
+    assert len(parsed.tools) == 1
+    assert parsed.tools[0].name == "list_issues"
+
+
+def test_read_parses_full_payload_with_serverinfo() -> None:
+    parsed = read_cached_tools(
+        _make_connector(
+            {
+                "cached_tools": {
+                    "discovered_at": "2026-05-20T10:00:00+00:00",
+                    "server_version": "1.2.3",
+                    "server_name": "atlassian-mcp",
+                    "transport": "streamable-http",
+                    "tools": [
+                        {"name": "create_issue", "input_schema": {}},
+                        {"name": "list_issues", "input_schema": {}},
+                    ],
+                }
+            }
+        )
+    )
+    assert parsed is not None
+    assert parsed.server_version == "1.2.3"
+    assert parsed.server_name == "atlassian-mcp"
+    assert parsed.transport == "streamable-http"
+    assert [t.name for t in parsed.tools] == ["create_issue", "list_issues"]
+
+
+def test_read_returns_none_for_corrupt_payload(caplog) -> None:
+    parsed = read_cached_tools(
+        _make_connector(
+            {
+                "cached_tools": {
+                    "discovered_at": "not-a-date",
+                    "tools": "should-be-a-list",
+                }
+            }
+        )
+    )
+    assert parsed is None
+    assert any("corrupt cached_tools" in r.getMessage() for r in caplog.records)
+
+
+def test_read_returns_none_when_tools_missing() -> None:
+    parsed = read_cached_tools(
+        _make_connector(
+            {"cached_tools": {"discovered_at": "2026-05-20T10:00:00+00:00"}}
+        )
+    )
+    assert parsed is None
+
+
+def test_tool_def_defaults_description_and_schema() -> None:
+    td = CachedMCPToolDef.model_validate({"name": "ping"})
+    assert td.description == ""
+    assert td.input_schema == {}
+
+
+def test_model_dump_json_mode_is_round_trippable() -> None:
+    original = CachedMCPTools(
+        discovered_at=datetime(2026, 5, 20, 10, 0, 0, tzinfo=UTC),
+        server_version="1.2.3",
+        server_name="atlassian-mcp",
+        transport="streamable-http",
+        tools=[CachedMCPToolDef(name="list_issues")],
+    )
+    payload = original.model_dump(mode="json")
+
+    assert payload["discovered_at"] == "2026-05-20T10:00:00Z"
+    assert payload["tools"][0]["name"] == "list_issues"
+
+    reparsed = CachedMCPTools.model_validate(payload)
+    assert reparsed.discovered_at == original.discovered_at
+    assert reparsed.tools[0].name == "list_issues"