feat(examples/python): add runnable example

Author: AgentPatterns

examples/agent-patterns/routing-agent/python/gateway.py

@@ -44,14 +44,22 @@ def _normalize_for_hash(value: Any) -> Any:
     return value
 
 
+def _normalize_ticket(value: str) -> str:
+    return " ".join(value.strip().split())
+
+
 def args_hash(args: dict[str, Any]) -> str:
     normalized = _normalize_for_hash(args or {})
     raw = _stable_json(normalized)
     return hashlib.sha256(raw.encode("utf-8")).hexdigest()[:12]
 
 
 def validate_route_action(
-    action: Any, *, allowed_routes: set[str]
+    action: Any,
+    *,
+    allowed_routes: set[str],
+    previous_target: str | None = None,
+    previous_status: str | None = None,
 ) -> dict[str, Any]:
     if not isinstance(action, dict):
         raise StopRun("invalid_route:not_object")
@@ -81,8 +89,13 @@ def validate_route_action(
     ticket = args.get("ticket")
     if not isinstance(ticket, str) or not ticket.strip():
         raise StopRun("invalid_route:missing_ticket")
+    ticket = _normalize_ticket(ticket)
+    normalized_args = {**args, "ticket": ticket}
+
+    if previous_status == "needs_reroute" and target == previous_target:
+        raise StopRun("invalid_route:repeat_target_after_reroute")
 
-    return {"kind": "route", "target": target, "args": args}
+    return {"kind": "route", "target": target, "args": normalized_args}
 
 
 class RouteGateway:

examples/agent-patterns/routing-agent/python/llm.py

@@ -25,6 +25,7 @@ class LLMEmpty(Exception):
 
 Rules:
 - Choose exactly one target from available_routes.
+- Never choose targets from forbidden_targets.
 - Keep args minimal and valid for that target.
 - If previous attempts failed with needs_reroute, choose a different target.
 - Respect routing budgets and avoid unnecessary retries.
@@ -97,6 +98,7 @@ def decide_route(
     *,
     max_route_attempts: int,
     remaining_attempts: int,
+    forbidden_targets: list[str],
 ) -> dict[str, Any]:
     recent_history = history[-3:]
     payload = {
@@ -105,6 +107,7 @@ def decide_route(
             "max_route_attempts": max_route_attempts,
             "remaining_attempts": remaining_attempts,
         },
+        "forbidden_targets": forbidden_targets,
         "state_summary": _build_state_summary(history),
         "recent_history": recent_history,
         "available_routes": ROUTE_CATALOG,

examples/agent-patterns/routing-agent/python/main.py

@@ -55,12 +55,36 @@ def run_routing(goal: str) -> dict[str, Any]:
                 "history": history,
             }
 
+        previous_step = history[-1] if history else None
+        previous_observation = (
+            previous_step.get("observation")
+            if isinstance(previous_step, dict)
+            else None
+        )
+        previous_route = previous_step.get("route") if isinstance(previous_step, dict) else None
+        previous_status = (
+            previous_observation.get("status")
+            if isinstance(previous_observation, dict)
+            else None
+        )
+        previous_target = (
+            previous_route.get("target")
+            if isinstance(previous_route, dict)
+            else None
+        )
+        forbidden_targets = (
+            [previous_target]
+            if previous_status == "needs_reroute" and isinstance(previous_target, str)
+            else []
+        )
+
         try:
             raw_route = decide_route(
                 goal=goal,
                 history=history,
                 max_route_attempts=BUDGET.max_route_attempts,
                 remaining_attempts=(BUDGET.max_route_attempts - attempt + 1),
+                forbidden_targets=forbidden_targets,
             )
         except LLMTimeout:
             return {
@@ -75,6 +99,8 @@ def run_routing(goal: str) -> dict[str, Any]:
             route_action = validate_route_action(
                 raw_route,
                 allowed_routes=ALLOWED_ROUTE_TARGETS_POLICY,
+                previous_target=previous_target,
+                previous_status=previous_status,
             )
         except StopRun as exc:
             return {
@@ -88,33 +114,6 @@ def run_routing(goal: str) -> dict[str, Any]:
 
         target = route_action["target"]
         route_args = route_action["args"]
-        previous_step = history[-1] if history else None
-        previous_observation = (
-            previous_step.get("observation")
-            if isinstance(previous_step, dict)
-            else None
-        )
-        previous_route = previous_step.get("route") if isinstance(previous_step, dict) else None
-        previous_status = (
-            previous_observation.get("status")
-            if isinstance(previous_observation, dict)
-            else None
-        )
-        previous_target = (
-            previous_route.get("target")
-            if isinstance(previous_route, dict)
-            else None
-        )
-
-        if previous_status == "needs_reroute" and target == previous_target:
-            return {
-                "status": "stopped",
-                "stop_reason": "invalid_route:repeat_target_after_reroute",
-                "phase": "route",
-                "route": route_action,
-                "trace": trace,
-                "history": history,
-            }
 
         try:
             observation = gateway.call(target, route_args)
@@ -166,6 +165,8 @@ def run_routing(goal: str) -> dict[str, Any]:
                 "stop_reason": "route_bad_observation",
                 "phase": "delegate",
                 "route": route_action,
+                "expected_statuses": ["needs_reroute", "done"],
+                "received_status": observation_status,
                 "bad_observation": observation,
                 "trace": trace,
                 "history": history,