Stop conditions - Phaseo Docs

Use stop conditions to give every agent a clear execution budget. Conditions are checked against completed steps and cumulative usage.

Combine built-in limits

import {
  maxCost,
  maxDuration,
  maxTokensUsed,
  stepCountIs,
} from "@phaseo/agent-sdk";

const agent = createAgent({
  id: "bounded-research",
  stopWhen: [
    stepCountIs(12),
    maxTokensUsed(40_000),
    maxCost(2),
    maxDuration(60_000),
  ],
});

The first matching condition records its reason and returns a run with status: "stopped".

Available helpers

Helper	Stops when
`stepCountIs(limit)`	The completed step count reaches the limit
`maxTokensUsed(limit)`	Cumulative token usage reaches the limit
`maxCost(limit)`	Cumulative reported cost reaches the limit
`maxDuration(ms)`	Elapsed runtime reaches the duration
`hasToolCall(name)`	A step contains the named tool call
`finishReasonIs(reason)`	A model step reports the finish reason

Add a custom condition

A condition can return false, true, or a reason string:

const stopAfterRepeatedFailures = ({ steps }) => {
  const failures = steps.filter((step) => step.status === "failed").length;
  return failures >= 2 ? "repeated_failures" : false;
};

const agent = createAgent({
  id: "support-agent",
  stopWhen: [stepCountIs(10), stopAfterRepeatedFailures],
});

Prefer a reason string when operators or product interfaces need to explain why a run ended.

Last modified on October 18, 2026