fix(ai): garantir une reponse finale quand la boucle d'agent epuise son budget (BUG-052)

tests/test_agent_loop.py

@@ -182,6 +182,40 @@ class TestConfirmationAndLimits:
         assert result.iterations == 2
         assert len(result.tool_calls) == 2
 
+    @pytest.mark.asyncio
+    async def test_max_iterations_synthesizes_final_answer(self, monkeypatch):
+        """BUG-052: exhausting the budget must still produce an answer."""
+        _register(monkeypatch, "_echo", lambda ctx, params: {"value": 1})
+        llm = ScriptedLLM([
+            LLMResponse(tool_calls=[ToolCall(id="1", name="_echo", arguments={})]),
+            LLMResponse(tool_calls=[ToolCall(id="2", name="_echo", arguments={})]),
+            LLMResponse(content="synthèse finale"),
+        ])
+        result = await run_agent(
+            [{"role": "user", "content": "loop"}], ctx=_ctx(), llm=llm, max_iterations=2
+        )
+        assert result.stopped == STOP_MAX_ITERATIONS
+        assert result.content == "synthèse finale"
+        # The last call is tool-less and carries the synthesis instruction.
+        assert llm.calls[-1]["tools"] == []
+        assert "N'appelle plus aucun outil" in llm.calls[-1]["messages"][-1]["content"]
+
+    @pytest.mark.asyncio
+    async def test_max_iterations_falls_back_to_sources(self, monkeypatch):
+        """An empty/failed synthesis still returns the gathered sources."""
+        _register(monkeypatch, "_search", lambda ctx, params: {
+            "results": [{"title": "T", "url": "https://ex.dev/a"}]
+        })
+        llm = ScriptedLLM([
+            LLMResponse(tool_calls=[ToolCall(id="1", name="_search", arguments={})]),
+            LLMResponse(content=""),
+        ])
+        result = await run_agent(
+            [{"role": "user", "content": "loop"}], ctx=_ctx(), llm=llm, max_iterations=1
+        )
+        assert result.stopped == STOP_MAX_ITERATIONS
+        assert "https://ex.dev/a" in result.content
+
 
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