diff --git a/langgraph/graph/graph.py b/langgraph/graph/graph.py
index 4caac7a16..b5e317334 100644
--- a/langgraph/graph/graph.py
+++ b/langgraph/graph/graph.py
@@ -29,6 +29,7 @@ class Graph:
         self.nodes: dict[str, Runnable] = {}
         self.edges = set[tuple[str, str]]()
         self.branches: defaultdict[str, list[Branch]] = defaultdict(list)
+        self.support_multiple_edges = False
 
     def add_node(self, key: str, action: RunnableLike) -> None:
         if key in self.nodes:
@@ -46,8 +47,9 @@ class Graph:
         if end_key not in self.nodes and end_key != END:
             raise ValueError(f"Need to add_node `{end_key}` first")
 
-        # TODO: support multiple message passing
-        if start_key in set(start for start, _ in self.edges):
+        if not self.support_multiple_edges and start_key in set(
+            start for start, _ in self.edges
+        ):
             raise ValueError(f"Already found path for {start_key}")
 
         self.edges.add((start_key, end_key))
@@ -111,7 +113,7 @@ class Graph:
             outgoing = outgoing_edges[key]
             edges_key = f"{key}:edges"
             if outgoing or key in self.branches:
-                nodes[edges_key] = Channel.subscribe_to(key)
+                nodes[edges_key] = Channel.subscribe_to(key, tags=["langsmith:hidden"])
             if outgoing:
                 nodes[edges_key] |= Channel.write_to(*[dest for dest in outgoing])
             if key in self.branches:
diff --git a/langgraph/graph/state.py b/langgraph/graph/state.py
index 3b708478a..5b5c658ca 100644
--- a/langgraph/graph/state.py
+++ b/langgraph/graph/state.py
@@ -21,6 +21,8 @@ class StateGraph(Graph):
         super().__init__()
         self.schema = schema
         self.channels = _get_channels(schema)
+        if any(isinstance(c, BinaryOperatorAggregate) for c in self.channels.values()):
+            self.support_multiple_edges = True
 
     def compile(self) -> Pregel:
         self.validate()
@@ -49,7 +51,9 @@ class StateGraph(Graph):
             outgoing = outgoing_edges[key]
             edges_key = f"{key}:edges"
             if outgoing or key in self.branches:
-                nodes[edges_key] = Channel.subscribe_to(key) | ChannelRead(state_keys)
+                nodes[edges_key] = Channel.subscribe_to(
+                    key, tags=["langsmith:hidden"]
+                ) | ChannelRead(state_keys)
             if outgoing:
                 nodes[edges_key] |= Channel.write_to(*[dest for dest in outgoing])
             if key in self.branches:
@@ -59,12 +63,12 @@ class StateGraph(Graph):
                     )
 
         nodes[START] = (
-            Channel.subscribe_to(f"{START}:inbox")
+            Channel.subscribe_to(f"{START}:inbox", tags=["langsmith:hidden"])
             | _update_state
             | Channel.write_to(START)
         )
         nodes[f"{START}:edges"] = (
-            Channel.subscribe_to(START)
+            Channel.subscribe_to(START, tags=["langsmith:hidden"])
             | ChannelRead(state_keys)
             | Channel.write_to(f"{self.entry_point}:inbox")
         )
diff --git a/langgraph/pregel/__init__.py b/langgraph/pregel/__init__.py
index c37a0e74c..b61381548 100644
--- a/langgraph/pregel/__init__.py
+++ b/langgraph/pregel/__init__.py
@@ -84,8 +84,10 @@ class Channel:
     def subscribe_to(
         cls,
         channels: str,
+        *,
         key: Optional[str] = None,
         when: Optional[Callable[[Any], bool]] = None,
+        tags: Optional[Sequence[str]] = None,
     ) -> ChannelInvoke:
         ...
 
@@ -94,8 +96,10 @@ class Channel:
     def subscribe_to(
         cls,
         channels: Sequence[str],
+        *,
         key: None = None,
         when: Optional[Callable[[Any], bool]] = None,
+        tags: Optional[Sequence[str]] = None,
     ) -> ChannelInvoke:
         ...
 
@@ -103,8 +107,10 @@ class Channel:
     def subscribe_to(
         cls,
         channels: Union[str, Sequence[str]],
+        *,
         key: Optional[str] = None,
         when: Optional[Callable[[Any], bool]] = None,
+        tags: Optional[Sequence[str]] = None,
     ) -> ChannelInvoke:
         """Runs process.invoke() each time channels are updated,
         with a dict of the channel values as input."""
@@ -121,6 +127,7 @@ class Channel:
             ),
             triggers=[channels] if isinstance(channels, str) else channels,
             when=when,
+            tags=tags,
         )
 
     @classmethod
@@ -154,6 +161,8 @@ class Pregel(
 
     hidden: Sequence[str] = Field(default_factory=list)
 
+    interrupt: Sequence[str] = Field(default_factory=list)
+
     input: Union[str, Sequence[str]] = "input"
 
     step_timeout: Optional[float] = None
@@ -222,13 +231,16 @@ class Pregel(
         run_manager: CallbackManagerForChainRun,
         config: RunnableConfig,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
     ) -> Iterator[Union[dict[str, Any], Any]]:
         if config["recursion_limit"] < 1:
             raise ValueError("recursion_limit must be at least 1")
         # assign defaults
-        if output is None:
-            output = [chan for chan in self.channels if chan not in self.hidden]
+        if output_keys is None:
+            output_keys = [chan for chan in self.channels if chan not in self.hidden]
+        if input_keys is None:
+            input_keys = self.input
         # copy nodes to ignore mutations during execution
         processes = {**self.nodes}
         # get checkpoint from saver, or create an empty one
@@ -242,7 +254,7 @@ class Pregel(
             _apply_writes(
                 checkpoint,
                 channels,
-                deque(w for c in input for w in map_input(self.input, c)),
+                deque(w for c in input for w in map_input(input_keys, c)),
                 config,
                 0,
             )
@@ -307,10 +319,10 @@ class Pregel(
                     print_checkpoint(step, channels)
 
                 # yield current value and checkpoint view
-                if step_output := map_output(output, pending_writes, channels):
+                if step_output := map_output(output_keys, pending_writes, channels):
                     yield step_output
                     # we can detect updates when output is multiple channels (ie. dict)
-                    if not isinstance(output, str):
+                    if not isinstance(output_keys, str):
                         # if view was updated, apply writes to channels
                         _apply_writes_from_view(checkpoint, channels, step_output)
 
@@ -319,6 +331,10 @@ class Pregel(
                     checkpoint = create_checkpoint(checkpoint, channels)
                     self.saver.put(config, checkpoint)
 
+                # interrupt if any channel written to is in interrupt list
+                if any(chan for chan, _ in pending_writes if chan in self.interrupt):
+                    break
+
             # save end of run checkpoint
             if self.saver is not None and self.saver.at == CheckpointAt.END_OF_RUN:
                 checkpoint = create_checkpoint(checkpoint, channels)
@@ -330,7 +346,8 @@ class Pregel(
         run_manager: AsyncCallbackManagerForChainRun,
         config: RunnableConfig,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
     ) -> AsyncIterator[Union[dict[str, Any], Any]]:
         if config["recursion_limit"] < 1:
             raise ValueError("recursion_limit must be at least 1")
@@ -344,8 +361,10 @@ class Pregel(
             None,
         )
         # assign defaults
-        if output is None:
-            output = [chan for chan in self.channels if chan not in self.hidden]
+        if output_keys is None:
+            output_keys = [chan for chan in self.channels if chan not in self.hidden]
+        if input_keys is None:
+            input_keys = self.input
         # copy nodes to ignore mutations during execution
         processes = {**self.nodes}
         # get checkpoint from saver, or create an empty one
@@ -357,7 +376,7 @@ class Pregel(
             _apply_writes(
                 checkpoint,
                 channels,
-                deque([w async for c in input for w in map_input(self.input, c)]),
+                deque([w async for c in input for w in map_input(input_keys, c)]),
                 config,
                 0,
             )
@@ -427,10 +446,10 @@ class Pregel(
                     print_checkpoint(step, channels)
 
                 # yield current value and checkpoint view
-                if step_output := map_output(output, pending_writes, channels):
+                if step_output := map_output(output_keys, pending_writes, channels):
                     yield step_output
                     # we can detect updates when output is multiple channels (ie. dict)
-                    if not isinstance(output, str):
+                    if not isinstance(output_keys, str):
                         # if view was updated, apply writes to channels
                         _apply_writes_from_view(checkpoint, channels, step_output)
 
@@ -439,6 +458,10 @@ class Pregel(
                     checkpoint = create_checkpoint(checkpoint, channels)
                     await self.saver.aput(config, checkpoint)
 
+                # interrupt if any channel written to is in interrupt list
+                if any(chan for chan, _ in pending_writes if chan in self.interrupt):
+                    break
+
             # save end of run checkpoint
             if self.saver is not None and self.saver.at == CheckpointAt.END_OF_RUN:
                 checkpoint = create_checkpoint(checkpoint, channels)
@@ -449,14 +472,16 @@ class Pregel(
         input: Union[dict[str, Any], Any],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> Union[dict[str, Any], Any]:
         latest: Union[dict[str, Any], Any] = None
         for chunk in self.stream(
             input,
             config,
-            output=output if output is not None else self.output,
+            output_keys=output_keys if output_keys is not None else self.output,
+            input_keys=input_keys,
             **kwargs,
         ):
             latest = chunk
@@ -467,21 +492,34 @@ class Pregel(
         input: Union[dict[str, Any], Any],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> Iterator[Union[dict[str, Any], Any]]:
-        return self.transform(iter([input]), config, output=output, **kwargs)
+        return self.transform(
+            iter([input]),
+            config,
+            output_keys=output_keys,
+            input_keys=input_keys,
+            **kwargs,
+        )
 
     def transform(
         self,
         input: Iterator[Union[dict[str, Any], Any]],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> Iterator[Union[dict[str, Any], Any]]:
         for chunk in self._transform_stream_with_config(
-            input, self._transform, config, output=output, **kwargs
+            input,
+            self._transform,
+            config,
+            output_keys=output_keys,
+            input_keys=input_keys,
+            **kwargs,
         ):
             yield chunk
 
@@ -490,14 +528,16 @@ class Pregel(
         input: Union[dict[str, Any], Any],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> Union[dict[str, Any], Any]:
         latest: Union[dict[str, Any], Any] = None
         async for chunk in self.astream(
             input,
             config,
-            output=output if output is not None else self.output,
+            output_keys=output_keys if output_keys is not None else self.output,
+            input_keys=input_keys,
             **kwargs,
         ):
             latest = chunk
@@ -508,14 +548,19 @@ class Pregel(
         input: Union[dict[str, Any], Any],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> AsyncIterator[Union[dict[str, Any], Any]]:
         async def input_stream() -> AsyncIterator[Union[dict[str, Any], Any]]:
             yield input
 
         async for chunk in self.atransform(
-            input_stream(), config, output=output, **kwargs
+            input_stream(),
+            config,
+            output_keys=output_keys,
+            input_keys=input_keys,
+            **kwargs,
         ):
             yield chunk
 
@@ -524,11 +569,17 @@ class Pregel(
         input: AsyncIterator[Union[dict[str, Any], Any]],
         config: Optional[RunnableConfig] = None,
         *,
-        output: Optional[Union[str, Sequence[str]]] = None,
+        output_keys: Optional[Union[str, Sequence[str]]] = None,
+        input_keys: Optional[Union[str, Sequence[str]]] = None,
         **kwargs: Any,
     ) -> AsyncIterator[Union[dict[str, Any], Any]]:
         async for chunk in self._atransform_stream_with_config(
-            input, self._atransform, config, output=output, **kwargs
+            input,
+            self._atransform,
+            config,
+            output_keys=output_keys,
+            input_keys=input_keys,
+            **kwargs,
         ):
             yield chunk
 
diff --git a/langgraph/pregel/read.py b/langgraph/pregel/read.py
index 11c1a050b..ebba367b9 100644
--- a/langgraph/pregel/read.py
+++ b/langgraph/pregel/read.py
@@ -90,6 +90,7 @@ class ChannelInvoke(RunnableBindingBase):
         channels: Mapping[None, str] | Mapping[str, str],
         triggers: Sequence[str],
         when: Optional[Callable[[Any], bool]] = None,
+        tags: Optional[Sequence[str]] = None,
         *,
         bound: Optional[Runnable[Any, Any]] = None,
         kwargs: Optional[Mapping[str, Any]] = None,
@@ -102,7 +103,7 @@ class ChannelInvoke(RunnableBindingBase):
             when=when,
             bound=bound or default_bound,
             kwargs=kwargs or {},
-            config=config,
+            config={**(config or {}), "tags": tags or []},
             **other_kwargs,
         )
 
diff --git a/tests/test_pregel.py b/tests/test_pregel.py
index ded25a5f5..7553e4bc6 100644
--- a/tests/test_pregel.py
+++ b/tests/test_pregel.py
@@ -44,7 +44,7 @@ def test_invoke_single_process_in_out(mocker: MockerFixture) -> None:
     assert app.input_schema.schema() == {"title": "LangGraphInput", "type": "integer"}
     assert app.output_schema.schema() == {"title": "LangGraphOutput", "type": "integer"}
     assert app.invoke(2) == 3
-    assert app.invoke(2, output=["output"]) == {"output": 3}
+    assert app.invoke(2, output_keys=["output"]) == {"output": 3}
     assert repr(app), "does not raise recursion error"
 
     assert gapp.invoke(2) == 3
@@ -157,6 +157,8 @@ def test_invoke_two_processes_in_out(mocker: MockerFixture) -> None:
 
     assert app.invoke(2) == 4
 
+    assert app.invoke(2, input_keys="inbox") == 3
+
     for step, values in enumerate(app.stream(2), start=1):
         if step == 1:
             assert values == {
@@ -238,7 +240,7 @@ def test_invoke_two_processes_in_dict_out(mocker: MockerFixture) -> None:
         input=["input", "inbox"],
     )
 
-    assert [*app.stream({"input": 2, "inbox": 12}, output="output")] == [
+    assert [*app.stream({"input": 2, "inbox": 12}, output_keys="output")] == [
         13,
         4,
     ]  # [12 + 1, 2 + 1 + 1]
@@ -259,7 +261,7 @@ def test_batch_two_processes_in_out() -> None:
     app = Pregel(nodes={"one": one, "two": two})
 
     assert app.batch([3, 2, 1, 3, 5]) == [5, 4, 3, 5, 7]
-    assert app.batch([3, 2, 1, 3, 5], output=["output"]) == [
+    assert app.batch([3, 2, 1, 3, 5], output_keys=["output"]) == [
         {"output": 5},
         {"output": 4},
         {"output": 3},
diff --git a/tests/test_pregel_async.py b/tests/test_pregel_async.py
index 3f94cf86d..cbd5406ad 100644
--- a/tests/test_pregel_async.py
+++ b/tests/test_pregel_async.py
@@ -42,7 +42,7 @@ async def test_invoke_single_process_in_out(mocker: MockerFixture) -> None:
     assert app.input_schema.schema() == {"title": "LangGraphInput", "type": "integer"}
     assert app.output_schema.schema() == {"title": "LangGraphOutput", "type": "integer"}
     assert await app.ainvoke(2) == 3
-    assert await app.ainvoke(2, output=["output"]) == {"output": 3}
+    assert await app.ainvoke(2, output_keys=["output"]) == {"output": 3}
 
     assert await gapp.ainvoke(2) == 3
 
@@ -157,6 +157,8 @@ async def test_invoke_two_processes_in_out(mocker: MockerFixture) -> None:
 
     assert await app.ainvoke(2) == 4
 
+    assert await app.ainvoke(2, input_keys="inbox") == 3
+
     step = 0
     async for values in app.astream(2):
         step += 1
@@ -247,7 +249,7 @@ async def test_invoke_two_processes_in_dict_out(mocker: MockerFixture) -> None:
 
     # [12 + 1, 2 + 1 + 1]
     assert [
-        c async for c in pubsub.astream({"input": 2, "inbox": 12}, output="output")
+        c async for c in pubsub.astream({"input": 2, "inbox": 12}, output_keys="output")
     ] == [13, 4]
     assert [c async for c in pubsub.astream({"input": 2, "inbox": 12})] == [
         {"inbox": [3], "output": 13},
@@ -269,7 +271,7 @@ async def test_batch_two_processes_in_out() -> None:
     )
 
     assert await app.abatch([3, 2, 1, 3, 5]) == [5, 4, 3, 5, 7]
-    assert await app.abatch([3, 2, 1, 3, 5], output=["output"]) == [
+    assert await app.abatch([3, 2, 1, 3, 5], output_keys=["output"]) == [
         {"output": 5},
         {"output": 4},
         {"output": 3},