from langchain.agents import create_agent
from langchain.agents.structured_output import ToolStrategy
from langchain_core.language_models.fake_chat_models import GenericFakeChatModel
from langchain_core.messages import AIMessage
from langgraph.checkpoint.memory import InMemorySaver
from pydantic import BaseModel, field_validator


class Answer(BaseModel):
    text: str

    @field_validator("text")
    @classmethod
    def not_bad(cls, v: str) -> str:
        if v == "BAD":
            raise ValueError("bad sentinel")
        return v


def msg(text: str, call_id: str) -> AIMessage:
    return AIMessage(content="", tool_calls=[{"name": "Answer", "args": {"text": text}, "id": call_id}])


class FakeModel(GenericFakeChatModel):
    def bind_tools(self, tools, **kwargs):
        return self


model = FakeModel(messages=iter([msg("Hi", "1"), msg("BAD", "2"), msg("Bye", "3")]))

agent = create_agent(
    model=model,
    tools=[],
    response_format=ToolStrategy(schema=Answer, handle_errors=True),
    checkpointer=InMemorySaver(),
)
thread = {"configurable": {"thread_id": "t"}}

r1 = agent.invoke({"messages": [("user", "say hi")]}, config=thread)
r2 = agent.invoke({"messages": [("user", "say bye")]}, config=thread)
print(r1["structured_response"], "|", r2["structured_response"])


"""
**Expected:** turn 2 returns `Answer(text='Bye')` (retry consumes the third queued response).
**Actual:** turn 2 returns `Answer(text='Hi')` — stale from turn 1; third response is never consumed.
"""

---



---

# _make_model_to_tools_edge, step 5 (factory.py:1752-1754)
if "structured_response" in state:
    return end_destination

# _make_model_to_model_edge, step 2 (factory.py:1779-1781)
if "structured_response" in state:
    return end_destination

---

System Information
------------------
> OS:  Darwin
> OS Version:  Darwin Kernel Version 25.4.0: Thu Mar 19 19:33:25 PDT 2026; root:xnu-12377.101.15~1/RELEASE_ARM64_T6041
> Python Version:  3.14.4 (v3.14.4:23116f998f6, Apr  7 2026, 09:45:22) [Clang 17.0.0 (clang-1700.6.4.2)]

Package Information
-------------------
> langchain_core: 1.2.8
> langchain: 1.2.8
> langsmith: 0.7.17
> langchain_anthropic: 1.3.1
> langchain_openai: 1.1.7
> langgraph_sdk: 0.3.3

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> anthropic: 0.77.0
> httpx: 0.28.1
> jsonpatch: 1.33
> langgraph: 1.0.7
> openai: 2.16.0
> orjson: 3.11.7
> packaging: 26.0
> pydantic: 2.12.5
> pyyaml: 6.0.3
> requests: 2.32.5
> requests-toolbelt: 1.0.0
> tenacity: 9.1.2
> tiktoken: 0.12.0
> typing-extensions: 4.15.0
> uuid-utils: 0.14.1
> websockets: 16.0
> xxhash: 3.6.0
> zstandard: 0.25.0