Don't require input schema in subagents (splunk#30)

mateusz834 · web-flow · commit 14580854cd56 · 2026-01-29T11:52:24.000+01:00
diff --git a/splunklib/ai/engines/langchain.py b/splunklib/ai/engines/langchain.py
@@ -218,10 +218,24 @@ def _denormalize_agent_name(name: str) -> str:
 
 
 def _agent_as_tool(agent: BaseAgent[OutputT]):
-    assert agent.name, "Agent must have a name to be used by other Agents"
-    assert agent.input_schema, (
-        "Agent must have an input schema to be used by other Agents"
-    )
+    if not agent.name:
+        raise AssertionError("Agent must have a name to be used by other Agents")
+
+    # TODO: we should enforce uniqueness of subagent names.
+
+    if agent.input_schema is None:
+
+        async def _run(content: str) -> str:
+            result = await agent.invoke([HumanMessage(content=content)])
+            assert agent.output_schema is None
+            return result.messages[-1].content
+
+        return StructuredTool.from_function(
+            coroutine=_run,
+            name=_normalize_agent_name(agent.name),
+            description=agent.description,
+            infer_schema=True,
+        )
 
     InputSchema = agent.input_schema
 
diff --git a/tests/integration/ai/test_agent.py b/tests/integration/ai/test_agent.py
@@ -262,6 +262,46 @@ class NicknameGeneratorInput(BaseModel):
             assert subagent_message, "No subagent message found in response"
             assert "Chris-zilla" in response, "Agent did generate valid nickname"
 
+    @pytest.mark.asyncio
+    async def test_subagent_without_input_schema(self):
+        pytest.importorskip("langchain_openai")
+        model = OpenAIModel(
+            model="ministral-3:8b",
+            base_url=OPENAI_BASE_URL,
+            api_key=OPENAI_API_KEY,
+            temperature=0.0,
+        )
+
+        async with (
+            Agent(
+                model=model,
+                system_prompt=(
+                    "You are a helpful assistant that generates nicknames"
+                    "If prompted for nickname you MUST append '-zilla' to provided name to create nickname."
+                    "Remember the dash and lowercase zilla. Example: Stefan -> Stefan-zilla"
+                ),
+                service=self.service,
+                name="NicknameGeneratorAgent",
+                description="Generates nicknames for people. Pass a name and get a nickname",
+            ) as subagent,
+            Agent(
+                model=model,
+                system_prompt="You are a supervisor agent that MUST use other agents",
+                agents=[subagent],
+                service=self.service,
+            ) as supervisor,
+        ):
+            result = await supervisor.invoke(
+                [
+                    HumanMessage(
+                        content="hi, my name is Chris. Generate a nickname for me",
+                    )
+                ]
+            )
+
+            response = result.messages[-1].content
+            assert "Chris-zilla" in response, "Agent did generate valid nickname"
+
     @pytest.mark.asyncio
     async def test_agent_understands_other_agents(self):
         pytest.importorskip("langchain_openai")
