Add FastAPI example

examples/model_serving/agent_fastapi_serving.py

@@ -0,0 +1,65 @@
+from fastapi import FastAPI
+from agents import Agent, Runner, InputGuardrail, GuardrailFunctionOutput
+from pydantic import BaseModel
+
+app = FastAPI()
+
+class Query(BaseModel):
+    query: str
+
+class HomeworkOutput(BaseModel):
+    is_homework: bool
+    reasoning: str
+
+general_agent = Agent(
+        name="Assistant",
+        instructions="You are a helpful assistant that can answer questions and help with tasks.",
+    )
+
+guardrail_agent = Agent(
+    name="Guardrail check",
+    instructions="Check if the user is asking about homework.",
+    output_type=HomeworkOutput,
+)
+
+math_tutor_agent = Agent(
+    name="Math Tutor",
+    handoff_description="Specialist agent for math questions",
+    instructions="You provide help with math problems. Explain your reasoning at each step and include examples",
+)
+
+history_tutor_agent = Agent(
+    name="History Tutor",
+    handoff_description="Specialist agent for historical questions",
+    instructions="You provide assistance with historical queries. Explain important events and context clearly.",
+)
+
+
+async def homework_guardrail(ctx, agent, input_data):
+    result = await Runner.run(guardrail_agent, input_data, context=ctx.context)
+    final_output = result.final_output_as(HomeworkOutput)
+    return GuardrailFunctionOutput(
+        output_info=final_output,
+        tripwire_triggered=not final_output.is_homework,
+    )
+
+triage_agent = Agent(
+    name="Triage Agent",
+    instructions="You determine which agent to use based on the user's homework question",
+    handoffs=[history_tutor_agent, math_tutor_agent],
+    input_guardrails=[
+        InputGuardrail(guardrail_function=homework_guardrail),
+    ],
+)
+
+@app.get("/")
+async def read_root():
+    result = await Runner.run(general_agent, "Tell me about SF.")
+    print(result.final_output)
+    return {"message": result.final_output}
+
+@app.post("/")
+async def read_root(query: Query):
+    result = await Runner.run(triage_agent, query.query)
+    print(result.final_output)
+    return {"message": result.final_output}