- 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_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_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 == ""