Fail CSVAnswers persistence closed

tests/test_full_stack_contract.py

@@ -50,6 +50,9 @@ def test_full_stack_product_contract():
     assert {"analyze_csv", "get_analysis", "analyze_csv_upload_base64", "analyze_csv_file", "list_analyses"} <= skill_names
     analyze_schema = next(skill.input_schema for skill in card.skills if skill.name == "analyze_csv")
     assert set(analyze_schema["required"]) == {"analysis_id", "csv_text", "question"}
+    assert analyze_schema["properties"]["analysis_id"]["maxLength"] == 128
+    assert analyze_schema["properties"]["csv_text"]["maxLength"] == agent_module.MAX_CSV_BYTES
+    assert analyze_schema["properties"]["question"]["maxLength"] == 500
     upload_schema = next(skill.input_schema for skill in card.skills if skill.name == "analyze_csv_file")
     assert upload_schema["properties"]["file"]["x-a2a-file-upload"]["max_bytes"] == agent_module.MAX_CSV_BYTES
     databases = card.runtime.platform_resources.databases
@@ -60,7 +63,7 @@ def test_full_stack_product_contract():
 
 
 def test_success_reload_and_receipt_persist_locally(monkeypatch):
-    monkeypatch.delenv("DATABASE_URL", raising=False)
+    monkeypatch.setattr(agent_module, "_connect", lambda: None)
     _reset_local_state_for_tests()
     app = CsvAnswersStudioV1()
 
@@ -92,7 +95,7 @@ def test_malformed_csv_rejected_deterministically(monkeypatch):
 
 
 def test_browser_base64_bridge(monkeypatch):
-    monkeypatch.delenv("DATABASE_URL", raising=False)
+    monkeypatch.setattr(agent_module, "_connect", lambda: None)
     _reset_local_state_for_tests()
     app = CsvAnswersStudioV1()
     upload = {
@@ -107,7 +110,7 @@ def test_browser_base64_bridge(monkeypatch):
 
 
 def test_mcp_tools_list_and_call(monkeypatch):
-    monkeypatch.delenv("DATABASE_URL", raising=False)
+    monkeypatch.setattr(agent_module, "_connect", lambda: None)
     _reset_local_state_for_tests()
     app = CsvAnswersStudioV1()
     server = MCPServer(app, context_builder=lambda skill_name: make_ctx(f"mcp-{skill_name}"))
@@ -140,3 +143,26 @@ def test_mcp_tools_list_and_call(monkeypatch):
         "params": {"name": "get_analysis", "arguments": {"analysis_id": "studio-csv-v1"}},
     }))
     assert reopened["result"]["structuredContent"]["ok"] is True
+
+
+def test_database_unavailable_fails_closed(monkeypatch):
+    def unavailable():
+        raise RuntimeError("database unavailable")
+
+    monkeypatch.setattr(agent_module, "_connect", unavailable)
+    app = CsvAnswersStudioV1()
+
+    result = run(
+        app.invoke(
+            "analyze_csv",
+            make_ctx(),
+            analysis_id="studio-csv-db-failure",
+            csv_text=SUCCESS_CSV,
+            question="Which month has the highest revenue?",
+        )
+    )
+
+    assert result.ok is False
+    assert result.code == "database_error"
+    assert result.saved is False
+    assert "RuntimeError" not in (result.message or "")