Additional agent DAG tests (#750)

- test_agent_provenance.py: test_session_parent_uri,
  test_session_no_parent_uri, and 6 synthesis tests (types,
  single/multiple parents, document, label)
- test_on_action_callback.py: 3 tests — fires before tool, skipped
  for Final, works when None
- test_callback_message_id.py: 7 tests — message_id on think/observe/
  answer callbacks (streaming + non-streaming) and
  send_final_response
- test_parse_chunk_message_id.py (5 tests) - _parse_chunk propagates
  message_id for thought, observation, answer; handles missing
  gracefully
- test_explainability_parsing.py (+1) -
  test_dispatches_analysis_with_tooluse - Analysis+ToolUse mixin still
  dispatches to Analysis
- test_explainability.py (+1) -
  test_observation_found_via_subtrace_synthesis
- chain walker follows from sub-trace Synthesis to find Observation
  and
  Conclusion in correct order
- test_agent_provenance.py (+8) - session parent_uri (2), synthesis
  single/multiple parents, types, document, label (6)

tests/unit/test_agent/test_callback_message_id.py

@@ -0,0 +1,122 @@
+"""
+Tests that streaming callbacks set message_id on AgentResponse.
+"""
+
+import pytest
+from unittest.mock import AsyncMock, MagicMock
+
+from trustgraph.agent.orchestrator.pattern_base import PatternBase
+from trustgraph.schema import AgentResponse
+
+
+@pytest.fixture
+def pattern():
+    processor = MagicMock()
+    return PatternBase(processor)
+
+
+class TestThinkCallbackMessageId:
+
+    @pytest.mark.asyncio
+    async def test_streaming_think_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/i1/thought"
+        think = pattern.make_think_callback(capture, streaming=True, message_id=msg_id)
+        await think("hello", is_final=False)
+
+        assert len(responses) == 1
+        assert responses[0].message_id == msg_id
+        assert responses[0].chunk_type == "thought"
+
+    @pytest.mark.asyncio
+    async def test_non_streaming_think_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/i1/thought"
+        think = pattern.make_think_callback(capture, streaming=False, message_id=msg_id)
+        await think("hello")
+
+        assert responses[0].message_id == msg_id
+        assert responses[0].end_of_message is True
+
+
+class TestObserveCallbackMessageId:
+
+    @pytest.mark.asyncio
+    async def test_streaming_observe_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/i1/observation"
+        observe = pattern.make_observe_callback(capture, streaming=True, message_id=msg_id)
+        await observe("result", is_final=True)
+
+        assert responses[0].message_id == msg_id
+        assert responses[0].chunk_type == "observation"
+
+
+class TestAnswerCallbackMessageId:
+
+    @pytest.mark.asyncio
+    async def test_streaming_answer_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/final"
+        answer = pattern.make_answer_callback(capture, streaming=True, message_id=msg_id)
+        await answer("the answer")
+
+        assert responses[0].message_id == msg_id
+        assert responses[0].chunk_type == "answer"
+
+    @pytest.mark.asyncio
+    async def test_no_message_id_default(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        answer = pattern.make_answer_callback(capture, streaming=True)
+        await answer("the answer")
+
+        assert responses[0].message_id == ""
+
+
+class TestSendFinalResponseMessageId:
+
+    @pytest.mark.asyncio
+    async def test_streaming_final_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/final"
+        await pattern.send_final_response(
+            capture, streaming=True, answer_text="answer",
+            message_id=msg_id,
+        )
+
+        # Should get content chunk + end-of-dialog marker
+        assert all(r.message_id == msg_id for r in responses)
+
+    @pytest.mark.asyncio
+    async def test_non_streaming_final_has_message_id(self, pattern):
+        responses = []
+        async def capture(r):
+            responses.append(r)
+
+        msg_id = "urn:trustgraph:agent:sess/final"
+        await pattern.send_final_response(
+            capture, streaming=False, answer_text="answer",
+            message_id=msg_id,
+        )
+
+        assert len(responses) == 1
+        assert responses[0].message_id == msg_id
+        assert responses[0].end_of_dialog is True

tests/unit/test_agent/test_explainability_parsing.py

@@ -22,6 +22,7 @@ from trustgraph.api.explainability import (
     TG_SYNTHESIS,
     TG_ANSWER_TYPE,
     TG_OBSERVATION_TYPE,
+    TG_TOOL_USE,
     TG_ANALYSIS,
     TG_CONCLUSION,
     TG_DOCUMENT,
@@ -76,6 +77,13 @@ class TestFromTriplesDispatch:
         entity = ExplainEntity.from_triples("urn:a", triples)
         assert isinstance(entity, Analysis)
 
+    def test_dispatches_analysis_with_tooluse(self):
+        """Analysis+ToolUse mixin still dispatches to Analysis."""
+        triples = _make_triples("urn:a",
+                                [PROV_ENTITY, TG_ANALYSIS, TG_TOOL_USE])
+        entity = ExplainEntity.from_triples("urn:a", triples)
+        assert isinstance(entity, Analysis)
+
     def test_dispatches_observation(self):
         triples = _make_triples("urn:o", [PROV_ENTITY, TG_OBSERVATION_TYPE])
         entity = ExplainEntity.from_triples("urn:o", triples)

tests/unit/test_agent/test_on_action_callback.py

@@ -0,0 +1,132 @@
+"""
+Tests for the on_action callback in react() — verifies that it fires
+after action selection but before tool execution.
+"""
+
+import pytest
+from unittest.mock import AsyncMock, MagicMock
+
+from trustgraph.agent.react.agent_manager import AgentManager
+from trustgraph.agent.react.types import Action, Final, Tool, Argument
+
+
+class TestOnActionCallback:
+
+    @pytest.mark.asyncio
+    async def test_on_action_called_for_tool_use(self):
+        """on_action fires when react() selects a tool (not Final)."""
+        call_log = []
+
+        async def fake_on_action(act):
+            call_log.append(("on_action", act.name))
+
+        # Tool that records when it's invoked
+        async def tool_invoke(**kwargs):
+            call_log.append(("tool_invoke",))
+            return "tool result"
+
+        tool_impl = MagicMock()
+        tool_impl.return_value.invoke = AsyncMock(side_effect=tool_invoke)
+
+        tools = {
+            "search": Tool(
+                name="search",
+                description="Search",
+                implementation=tool_impl,
+                arguments=[Argument(name="query", type="string", description="q")],
+                config={},
+            ),
+        }
+
+        agent = AgentManager(tools=tools)
+
+        # Mock reason() to return an Action
+        action = Action(thought="thinking", name="search", arguments={"query": "test"}, observation="")
+        agent.reason = AsyncMock(return_value=action)
+
+        think = AsyncMock()
+        observe = AsyncMock()
+        context = MagicMock()
+
+        await agent.react(
+            question="test",
+            history=[],
+            think=think,
+            observe=observe,
+            context=context,
+            on_action=fake_on_action,
+        )
+
+        # on_action should fire before tool_invoke
+        assert len(call_log) == 2
+        assert call_log[0] == ("on_action", "search")
+        assert call_log[1] == ("tool_invoke",)
+
+    @pytest.mark.asyncio
+    async def test_on_action_not_called_for_final(self):
+        """on_action does not fire when react() returns Final."""
+        called = []
+
+        async def fake_on_action(act):
+            called.append(act)
+
+        agent = AgentManager(tools={})
+        agent.reason = AsyncMock(
+            return_value=Final(thought="done", final="answer")
+        )
+
+        think = AsyncMock()
+        observe = AsyncMock()
+        context = MagicMock()
+
+        result = await agent.react(
+            question="test",
+            history=[],
+            think=think,
+            observe=observe,
+            context=context,
+            on_action=fake_on_action,
+        )
+
+        assert isinstance(result, Final)
+        assert len(called) == 0
+
+    @pytest.mark.asyncio
+    async def test_on_action_none_accepted(self):
+        """react() works fine when on_action is None (default)."""
+        async def tool_invoke(**kwargs):
+            return "result"
+
+        tool_impl = MagicMock()
+        tool_impl.return_value.invoke = AsyncMock(side_effect=tool_invoke)
+
+        tools = {
+            "search": Tool(
+                name="search",
+                description="Search",
+                implementation=tool_impl,
+                arguments=[],
+                config={},
+            ),
+        }
+
+        agent = AgentManager(tools=tools)
+        agent.reason = AsyncMock(
+            return_value=Action(thought="t", name="search", arguments={}, observation="")
+        )
+
+        think = AsyncMock()
+        observe = AsyncMock()
+        context = MagicMock()
+
+        result = await agent.react(
+            question="test",
+            history=[],
+            think=think,
+            observe=observe,
+            context=context,
+            # on_action not passed — defaults to None
+        )
+
+        assert isinstance(result, Action)
+        assert result.observation == "result"

tests/unit/test_agent/test_parse_chunk_message_id.py

@@ -0,0 +1,74 @@
+"""
+Tests that _parse_chunk propagates message_id from wire format
+to AgentThought, AgentObservation, and AgentAnswer.
+"""
+
+import pytest
+
+from trustgraph.api.socket_client import SocketClient
+from trustgraph.api.types import AgentThought, AgentObservation, AgentAnswer
+
+
+@pytest.fixture
+def client():
+    # We only need _parse_chunk — don't connect
+    c = object.__new__(SocketClient)
+    return c
+
+
+class TestParseChunkMessageId:
+
+    def test_thought_message_id(self, client):
+        resp = {
+            "chunk_type": "thought",
+            "content": "thinking...",
+            "end_of_message": False,
+            "message_id": "urn:trustgraph:agent:sess/i1/thought",
+        }
+        chunk = client._parse_chunk(resp)
+        assert isinstance(chunk, AgentThought)
+        assert chunk.message_id == "urn:trustgraph:agent:sess/i1/thought"
+
+    def test_observation_message_id(self, client):
+        resp = {
+            "chunk_type": "observation",
+            "content": "result",
+            "end_of_message": True,
+            "message_id": "urn:trustgraph:agent:sess/i1/observation",
+        }
+        chunk = client._parse_chunk(resp)
+        assert isinstance(chunk, AgentObservation)
+        assert chunk.message_id == "urn:trustgraph:agent:sess/i1/observation"
+
+    def test_answer_message_id(self, client):
+        resp = {
+            "chunk_type": "answer",
+            "content": "the answer",
+            "end_of_message": False,
+            "end_of_dialog": False,
+            "message_id": "urn:trustgraph:agent:sess/final",
+        }
+        chunk = client._parse_chunk(resp)
+        assert isinstance(chunk, AgentAnswer)
+        assert chunk.message_id == "urn:trustgraph:agent:sess/final"
+
+    def test_thought_missing_message_id(self, client):
+        resp = {
+            "chunk_type": "thought",
+            "content": "thinking...",
+            "end_of_message": False,
+        }
+        chunk = client._parse_chunk(resp)
+        assert isinstance(chunk, AgentThought)
+        assert chunk.message_id == ""
+
+    def test_answer_missing_message_id(self, client):
+        resp = {
+            "chunk_type": "answer",
+            "content": "answer",
+            "end_of_message": True,
+            "end_of_dialog": True,
+        }
+        chunk = client._parse_chunk(resp)
+        assert isinstance(chunk, AgentAnswer)
+        assert chunk.message_id == ""