Idempotent approved side effects

"""OpenAI Agents SDK 0.24.0: keep an approved side effect from running twice.
Real failure modes shown (the SDK itself does NOT re-run an approved tool on a single resume):
  A) duplicate resume: the same saved RunState gets resumed twice (double-click, worker retry, queue redelivery)
  B) whole-run retry: the run crashes AFTER the tool ran (here: the model call fails), app retries from scratch
NAIVE tool: charges every time it's invoked.  FIXED tool: idempotency key from stable run data
(order_id from the run context + tool name), deduped by the (fake) payment API.
MOCK: only the model (fake_model.ScriptedModel, a real agents.Model subclass) and the payment API."""
import asyncio
from dataclasses import dataclass
from agents import Agent, Runner, RunConfig, RunState, RunContextWrapper, function_tool
from agents.tool_context import ToolContext
from fake_model import ScriptedModel

class FakePaymentAPI:
    def __init__(self): self.charges = []; self.by_key = {}
    def charge(self, amount, key=None):
        if key and key in self.by_key: return self.by_key[key]
        cid = f"ch_{len(self.charges)+1}"; self.charges.append((cid, amount))
        if key: self.by_key[key] = cid
        return cid

@dataclass
class Ctx:
    order_id: str
    api: FakePaymentAPI

@function_tool(needs_approval=True)
def charge_naive(ctx: RunContextWrapper[Ctx], amount: int) -> str:

# ... PREVIEW ENDS HERE: first 28 of 84 lines (setup + the NAIVE version).
# The FIXED version and the runnable scenarios are in the Signal Pro pack.

openai-agents==0.24.0

RunState context of type Ctx is not serializable; storing empty context. Provide context_serializer to preserve it.
RunState context of type Ctx is not serializable; storing empty context. Provide context_serializer to preserve it.
== NAIVE / A) duplicate resume ==
  paused: ['charge_naive'], charges=0
  after 2 resumes of same snapshot: charges=[('ch_1', 1999), ('ch_2', 1999)]
== NAIVE / B) retry after crash ==
  attempt 1: failed after tool ran (model API 503 (simulated)); charges so far=1; retrying from scratch
  attempt 2: ok -> Model saw tool outputs: call_0=ch_2
  final charges=[('ch_1', 1999), ('ch_2', 1999)]
== FIXED / A) duplicate resume ==
  paused: ['charge_fixed'], charges=0
  after 2 resumes of same snapshot: charges=[('ch_1', 1999)]
== FIXED / B) retry after crash ==
  attempt 1: failed after tool ran (model API 503 (simulated)); charges so far=1; retrying from scratch
  attempt 2: ok -> Model saw tool outputs: call_0=ch_1
  final charges=[('ch_1', 1999)]

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