fix: ensure args delta on manual tool call are always string (#472)

ranst91 · web-flow · commit 58dbafd624c5 · 2025-10-03T18:13:08.000+02:00
diff --git a/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py b/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py
@@ -651,7 +651,13 @@ async def _handle_single_event(self, event: Any, state: State) -> AsyncGenerator
                     )
                 )
                 yield self._dispatch_event(
-                    ToolCallArgsEvent(type=EventType.TOOL_CALL_ARGS, tool_call_id=event["data"]["id"], delta=event["data"]["args"], raw_event=event)
+                    ToolCallArgsEvent(
+                        type=EventType.TOOL_CALL_ARGS,
+                        tool_call_id=event["data"]["id"],
+                        delta=event["data"]["args"] if isinstance(event["data"]["args"], str) else json.dumps(
+                            event["data"]["args"]),
+                        raw_event=event
+                    )
                 )
                 yield self._dispatch_event(
                     ToolCallEndEvent(type=EventType.TOOL_CALL_END, tool_call_id=event["data"]["id"], raw_event=event)

Original file line number	Diff line number	Diff line change
`@@ -651,7 +651,13 @@ async def _handle_single_event(self, event: Any, state: State) -> AsyncGenerator`
`651`	`651`	`)`
`652`	`652`	`)`
`653`	`653`	`yield self._dispatch_event(`
`654`		`- ToolCallArgsEvent(type=EventType.TOOL_CALL_ARGS, tool_call_id=event["data"]["id"], delta=event["data"]["args"], raw_event=event)`
	`654`	`+ ToolCallArgsEvent(`
	`655`	`+ type=EventType.TOOL_CALL_ARGS,`
	`656`	`+ tool_call_id=event["data"]["id"],`
	`657`	`+ delta=event["data"]["args"] if isinstance(event["data"]["args"], str) else json.dumps(`
	`658`	`+ event["data"]["args"]),`
	`659`	`+ raw_event=event`
	`660`	`+ )`
`655`	`661`	`)`
`656`	`662`	`yield self._dispatch_event(`
`657`	`663`	`ToolCallEndEvent(type=EventType.TOOL_CALL_END, tool_call_id=event["data"]["id"], raw_event=event)`