fix: Address remaining PR review feedback

- Cache node trackers in langgraph_callback_handler flush() to avoid
  creating multiple trackers per node with different runIds
- Read graph key directly from config instead of instantiating a
  tracker just for debug logging in langgraph_agent_graph_runner
- Simplify redundant except (json.JSONDecodeError, Exception) to
  except Exception in tracker.py from_resumption_token

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jsonbailey

packages/ai-providers/server-ai-langchain/src/ldai_langchain/langgraph_agent_graph_runner.py

@@ -260,8 +260,7 @@ def route(state: WorkflowState) -> str:
 
         self._graph.traverse(fn=handle_traversal)
 
-        tracker = self._graph.create_tracker() if self._graph.create_tracker is not None else None
-        graph_key_str = tracker.graph_key if tracker else 'unknown'
+        graph_key_str = self._graph._agent_graph.key or 'unknown'
         log.debug(
             f"LangGraphAgentGraphRunner: graph='{graph_key_str}', root='{root_key}', "
             f"structure: {' | '.join(graph_structure)}"

packages/ai-providers/server-ai-langchain/src/ldai_langchain/langgraph_callback_handler.py

@@ -196,13 +196,17 @@ def flush(self, graph: AgentGraphDefinition) -> None:
 
         :param graph: The AgentGraphDefinition whose nodes hold the LD config trackers.
         """
+        node_trackers: Dict[str, Any] = {}
         for node_key in self._path:
+            if node_key in node_trackers:
+                continue
             node = graph.get_node(node_key)
             if not node:
                 continue
             config_tracker = node.get_config().create_tracker()
             if not config_tracker:
                 continue
+            node_trackers[node_key] = config_tracker
 
             usage = self._node_tokens.get(node_key)
             if usage:

packages/sdk/server-ai/src/ldai/tracker.py

@@ -153,7 +153,7 @@ def from_resumption_token(cls, token: str, ld_client: LDClient, context: Context
             payload = json.loads(
                 base64.urlsafe_b64decode(padded.encode("utf-8")).decode("utf-8")
             )
-        except (json.JSONDecodeError, Exception) as e:
+        except Exception as e:
             return Result.fail(f"Invalid resumption token: {e}", e)
 
         for field in ("runId", "configKey", "version"):