feat(conditions): SHACKLE — budget-enforcing, loop-detecting termination condition

[Fame510]

Summary

Adds ShackleGuard — a pre-execution circuit breaker as an AutoGen TerminationCondition.

Usage:

from autogen_agentchat.conditions import ShackleGuard

guard = ShackleGuard(budget=0.25, max_repeat_calls=3, timeout_seconds=300)
team.run(task, termination_condition=guard)

What it does

Monitors both ToolCallRequestEvent (before execution) and ToolCallExecutionEvent (after execution) across all agents in a team.

Guard layers:

1. Budget enforcement — stops team when cumulative tool cost exceeds budget
2. Loop detection — blocks repeated identical tool calls
3. Error amplification — tightens repeat limits when 401/403/500/timeout detected
4. Wall-clock timeout — caps session duration
5. Circuit breaker — once tripped, raises TerminatedException

Motivation

Directly addresses #7770 — the $106K AWS disaster where an agent destroyed infrastructure because no pre-execution budget guard existed. This condition would have terminated the team at $0.25.

Fully implements the TerminationCondition and Component protocols — drop-in compatible with any AutoGen team.

[Fame510]

@microsoft-github-policy-service agree company="Sovereign Logic"