test(harness): a Deep Agents reference agent for the hosted path (TH-8810)

.github/workflows/sdk-smoke.yml

@@ -97,6 +97,7 @@ jobs:
           tests/harness/test_agent_type_refusal.py
           tests/harness/test_python_source_codecs.py
           tests/harness/test_executor_completed_counts.py
+          tests/harness/test_deep_agents_reference.py
           tests/harness/test_reading_entry.py
           tests/harness/test_agent_reading.py
           tests/harness/test_scan_walk.py

examples/harness/deep_agents_support/.python-version

@@ -0,0 +1 @@
+3.12

examples/harness/deep_agents_support/README.md

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+# Deep Agents support agent
+
+A customer support chat agent built on LangChain's Deep Agents. It has three tools over a
+small in-memory set of orders: `look_up_order`, `start_return` and `return_policy`.
+
+## How the kit runs it
+
+`langgraph.json` names the one graph, `agent.py:graph`, which is built once when the module
+is imported. The kit runs it with its LangGraph adapter: each turn the adapter sends the
+whole conversation as `messages` and replies with the last message's text. Tool calls are
+not returned: the graph runs the tools itself, and the kit's tool tracer records each call
+made to the three tool functions, including the ones made from a worker thread. Deep
+Agents' own built-in tools (files, planning, sub-agents) are not traced.
+
+## Environment
+
+- `OPENAI_API_KEY`: the key for the endpoint (required for a turn; without it the module
+  still imports, with a placeholder key, and the turn fails).
+- `OPENAI_BASE_URL`: the endpoint's base URL. Set it to the model gateway for the default model; unset means the OpenAI API, which then needs `OPENAI_MODEL` set to an OpenAI model.
+- `OPENAI_MODEL`: the model name, default `vertex_ai/gemini-3.7-flash` (a gateway name).
+
+The endpoint must speak chat completions: the model is built with `use_responses_api=False`.
+Install with `pip install -r requirements.txt` on Python 3.12.

examples/harness/deep_agents_support/agent.py

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+import os
+
+from deepagents import create_deep_agent
+from langchain_openai import ChatOpenAI
+
+MODEL = os.getenv("OPENAI_MODEL", "vertex_ai/gemini-3.7-flash")
+
+_ORDERS = {
+    "A1001": {"item": "trail running shoes", "status": "delivered", "return": None},
+    "A1002": {"item": "rain jacket", "status": "shipped", "return": None},
+    "A1003": {"item": "water bottle", "status": "delivered", "return": None},
+}
+
+
+def look_up_order(order_id: str) -> str:
+    """Look up an order by its id and report its item, status and any return."""
+    order = _ORDERS.get(order_id)
+    if order is None:
+        return f"No order {order_id} exists."
+    returned = order["return"] or "none"
+    return f"Order {order_id}: {order['item']}, status {order['status']}, return: {returned}."
+
+
+def start_return(order_id: str, reason: str) -> str:
+    """Start a return for a delivered order, giving the customer's reason."""
+    order = _ORDERS.get(order_id)
+    if order is None:
+        return f"No order {order_id} exists."
+    if order["status"] != "delivered":
+        return f"Order {order_id} is {order['status']} and cannot be returned yet."
+    if order["return"] is not None:
+        return f"Order {order_id} already has a return started."
+    order["return"] = reason
+    return f"Return started for order {order_id}: {reason}."
+
+
+def return_policy() -> str:
+    """State the store's return policy."""
+    return "Delivered items can be returned within 30 days for a full refund."
+
+
+# Built once at import, which is how a graph named in langgraph.json is loaded. The client
+# is built eagerly and refuses a missing key, so a placeholder keeps the import alive and
+# the turn is what fails without a real key. `use_responses_api=False` because ChatOpenAI
+# switches to the Responses API by itself for some models and arguments, and the gateway
+# serves that only for OpenAI-format routes.
+graph = create_deep_agent(
+    model=ChatOpenAI(
+        model=MODEL,
+        base_url=os.getenv("OPENAI_BASE_URL"),
+        api_key=os.getenv("OPENAI_API_KEY") or "unset",
+        use_responses_api=False,
+    ),
+    tools=[look_up_order, start_return, return_policy],
+    system_prompt=(
+        "You are a customer support agent for an online store. Use the order tools to "
+        "look up orders and start returns, and never guess an order's status. Answer "
+        "briefly."
+    ),
+)

examples/harness/deep_agents_support/langgraph.json

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+{
+  "dependencies": ["."],
+  "graphs": {
+    "support": "./agent.py:graph"
+  }
+}

examples/harness/deep_agents_support/requirements.txt

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+deepagents==0.7.32
+langchain-openai==1.7.3