refactor: streamline chat flow and improve diagnostics

Store server.log inside OLLAMA_WEB_DATA_DIR and manage the ollama-web file handler through the Starlette lifespan. Close and detach the handler on shutdown to prevent duplicate records and Windows file locks when applications are recreated.

Stop converting DuckDuckGo provider failures into empty search results. Record a query-safe traceback, re-raise the original exception, and let ToolRegistry expose the exception type and message as a tool error without adding or spoofing Referer headers.

Remove the unused non-streaming chat_with_tools implementation and its private helpers. Move capability, options, standard tool, MCP tool, and final tools=[] regression coverage onto the production streaming path.

Add integration coverage for data/server.log placement, handler cleanup, repeated lifespans, and provider 403 diagnostics. Update the Unreleased changelog entry.

Validated with 118 tests, Ruff, mypy, diff checks, real DuckDuckGo searches, successful result-page fetches, and observable 401/403 responses from sites that reject automated retrieval.

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/test_tools.py b/tests/test_tools.py
index a94ea52..387cbe2 100644
--- a/tests/test_tools.py
+++ b/tests/test_tools.py
@@ -114,6 +114,55 @@ def test_web_search_mocked():
     assert result[0]["title"] == "T"
 
 
+def test_web_search_returns_empty_list_for_no_provider_results() -> None:
+    from ollama_web.tools import search as search_mod
+
+    class EmptyDDGS:
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *args):
+            return None
+
+        def text(self, query, max_results=5):
+            return []
+
+    with patch.object(search_mod, "DDGS", EmptyDDGS):
+        assert search_mod.web_search("nothing found") == []
+
+
+def test_web_search_logs_and_propagates_provider_errors(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    from ollama_web.tools import search as search_mod
+
+    class FailingDDGS:
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *args):
+            return None
+
+        def text(self, query, max_results=5):
+            raise RuntimeError("403 Forbidden")
+
+    with (
+        patch.object(search_mod, "DDGS", FailingDDGS),
+        caplog.at_level("ERROR", logger="ollama_web.tools.search"),
+    ):
+        with pytest.raises(RuntimeError, match="403 Forbidden"):
+            search_mod.web_search("private search terms")
+
+    assert "DuckDuckGo web search failed" in caplog.text
+    assert "private search terms" not in caplog.text
+
+    registry = ToolRegistry()
+    registry.register(search_mod.web_search)
+    with patch.object(search_mod, "DDGS", FailingDDGS):
+        result = json.loads(registry.execute("web_search", {"query": "test"}))
+    assert result == {"error": "RuntimeError: 403 Forbidden"}
+
+
 # ---------------------------------------------------------------------------
 # scrape_url tests (existing + pagination)
 # ---------------------------------------------------------------------------