a2a-source-edit: write agent.py

agent.py

@@ -63,6 +63,10 @@ class QuoteJudgeStudioV1Config(BaseModel):
     """Runtime config is intentionally empty; the app uses platform auth + DB."""
 
 
+class QuoteJudgeState(BaseModel):
+    """Card-visible durable state marker; data lives in managed Postgres."""
+
+
 class QuoteInput(BaseModel):
     vendor: str = Field(..., min_length=1, max_length=120)
     quantity: int = Field(..., ge=1, le=1_000_000)
@@ -129,6 +133,7 @@ class QuoteJudgeStudioV1(A2AAgent[QuoteJudgeStudioV1Config, PlatformUserAuth]):
     auth_model = PlatformUserAuth
 
     state = State.DURABLE
+    state_model = QuoteJudgeState
     pricing = Pricing(
         price_per_call_usd=0.0,
         caller_pays_llm=False,