feature: Implement post_model_hook and HumanInterruptNode (#4583)

2026-09-12 04:37:51 +02:00 · 2025-05-19 14:07:42 -04:00
parent 95f92069a7
commit 7bd8616b1e
5 changed files with 579 additions and 25 deletions
@@ -0,0 +1,191 @@
+import pytest
+from langchain_core.messages import ToolMessage
+from langchain_core.runnables import RunnableConfig
+
+from langgraph.checkpoint.base import BaseCheckpointSaver
+from langgraph.prebuilt import create_react_agent
+from langgraph.prebuilt.interrupt import HumanInterruptConfig, InterruptToolNode
+from langgraph.types import Command
+from tests.model import FakeToolCallingModel
+
+
+def hello_tool(name: str) -> str:
+    """Return a greeting for the provided person."""
+    return f"Hello, {name}!"
+
+
+post_model_hook = InterruptToolNode(
+    hello_tool=HumanInterruptConfig(
+        allow_accept=True,
+        allow_edit=True,
+        allow_ignore=True,
+        allow_respond=True,
+    )
+)
+
+default_model = FakeToolCallingModel(
+    tool_calls=[
+        [
+            {
+                "name": "hello_tool",
+                "args": {"name": "lady gaga"},
+                "id": "some-random-id",
+            }
+        ]
+    ]
+)
+
+
+def test_interrupt_surfaced(
+    request: pytest.FixtureRequest,
+    sync_checkpointer: BaseCheckpointSaver,
+) -> None:
+    agent = create_react_agent(
+        default_model,
+        [hello_tool],
+        checkpointer=sync_checkpointer,
+        post_model_hook=post_model_hook,
+    )
+    config: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    result = agent.invoke({"messages": [("user", "Say hi to lady gaga!")]}, config)
+
+    interrupt_data = result["__interrupt__"]
+    assert interrupt_data[0].value == [
+        {
+            "action_request": {"action": "hello_tool", "args": {"name": "lady gaga"}},
+            "config": {
+                "allow_accept": True,
+                "allow_edit": True,
+                "allow_ignore": True,
+                "allow_respond": True,
+            },
+            "description": "Please review tool call for `hello_tool` before execution.",
+        }
+    ]
+
+    response = agent.invoke(Command(resume={"type": "accept"}), config=config)
+    tool_message: ToolMessage = response["messages"][-2]
+    assert tool_message.content == "Hello, lady gaga!"
+    assert tool_message.name == "hello_tool"
+
+
+@pytest.mark.parametrize(
+    "resume, expected_content",
+    [
+        ({"type": "accept"}, "Hello, lady gaga!"),
+        (
+            {"type": "ignore"},
+            "User ignored the tool call for `hello_tool` with id some-random-id",
+        ),
+        (
+            {
+                "type": "edit",
+                "args": {"action": "hello_tool", "args": {"name": "bruno mars"}},
+            },
+            "Hello, bruno mars!",
+        ),
+    ],
+)
+def test_interrupt_resume_variants(
+    request: pytest.FixtureRequest,
+    sync_checkpointer: BaseCheckpointSaver,
+    resume: dict,
+    expected_content: str,
+) -> None:
+    agent = create_react_agent(
+        default_model,
+        [hello_tool],
+        checkpointer=sync_checkpointer,
+        post_model_hook=post_model_hook,
+    )
+
+    config: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    agent.invoke({"messages": [("user", "Say hi to lady gaga!")]}, config)
+
+    response = agent.invoke(Command(resume=resume), config=config)
+    tool_message: ToolMessage = response["messages"][-2]
+    assert tool_message.name == "hello_tool"
+    assert tool_message.content == expected_content
+
+    if resume["type"] == "edit":
+        ai_msg = response["messages"][-1]
+        assert ai_msg.tool_calls == [
+            {
+                "name": "hello_tool",
+                "args": {"name": "lady gaga"},
+                "id": "some-random-id",
+                "type": "tool_call",
+            }
+        ]
+
+
+def test_resume_with_response(
+    request: pytest.FixtureRequest,
+    sync_checkpointer: BaseCheckpointSaver,
+) -> None:
+    model = FakeToolCallingModel(
+        tool_calls=[
+            [
+                {
+                    "name": "hello_tool",
+                    "args": {"name": "lady gaga"},
+                    "id": "some-random-id",
+                }
+            ],
+            [
+                {
+                    "name": "hello_tool",
+                    "args": {"name": "bruno mars"},
+                    "id": "some-random-id-2",
+                }
+            ],
+        ]
+    )
+
+    agent = create_react_agent(
+        model,
+        [hello_tool],
+        checkpointer=sync_checkpointer,
+        post_model_hook=post_model_hook,
+    )
+
+    config: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    agent.invoke({"messages": [("user", "Say hi to lady gaga!")]}, config)
+
+    # Provide user response
+    agent.invoke(
+        Command(
+            resume={
+                "type": "response",
+                "args": "actually, please say hello to bruno mars",
+            }
+        ),
+        config=config,
+    )
+
+    # Accept the updated call
+    response = agent.invoke(Command(resume={"type": "accept"}), config=config)
+
+    assert len(response["messages"]) == 6
+    tool_message: ToolMessage = response["messages"][-2]
+    assert tool_message.name == "hello_tool"
+    assert tool_message.content == "Hello, bruno mars!"
+
+
+def test_resume_with_type_not_allowed(sync_checkpointer: BaseCheckpointSaver) -> None:
+    agent = create_react_agent(
+        default_model,
+        [hello_tool],
+        checkpointer=sync_checkpointer,
+        post_model_hook=post_model_hook,
+    )
+    config: RunnableConfig = {"configurable": {"thread_id": "1"}}
+    agent.invoke({"messages": [("user", "Say hi to lady gaga!")]}, config)
+
+    with pytest.raises(ValueError) as exc_info:
+        agent.invoke(Command(resume={"type": "not-allowed"}), config=config)
+
+    assert (
+        str(exc_info.value)
+        == "Unexpected human response: {'type': 'not-allowed'}. Expected one with `'type'` in ['accept', 'edit', 'response', 'ignore'] based on hello_tool's interrupt configuration."
+    )