Composable Termination Conditions

Problem

Inlining these stop conditions as ad-hoc `if` statements in the orchestrator loop scatters the termination logic, makes its precedence implicit, and prevents reuse across loops. Adding a new condition requires editing the loop. Combining conditions (stop on max_messages OR external signal AND a specific tool call) becomes an unreadable nest. Operators reading a trace cannot tell why a run ended without re-reading the loop code.

Solution

Define a small set of primitive termination conditions: MaxMessages, TokenBudget, TextMention, FunctionCall, Handoff, Timeout, ExternalSignal, Cancellation. Each implements a single method `is_terminated(state) -> bool, reason`. Define a Composite that combines conditions with `any` (OR) or `all` (AND) semantics. The orchestrator loop consults the composite once per step. The trip cause (which leaf condition fired) is logged with the termination event.

When to use

• An agent loop must combine multiple heterogeneous stop criteria.
• Operators need structured trip-cause for postmortem.
• External signals (cancellation, kill-switch) need to share termination semantics with intrinsic stops.