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Workflow.until()

The .until() method repeats a step until a specified condition becomes true. This creates a loop that continues executing the specified step until the condition is satisfied.

Usage​

workflow.step(incrementStep).until(condition, incrementStep).then(finalStep);

Parameters​

condition:

Function | ReferenceCondition
A function or reference condition that determines when to stop looping

step:

Step
The step to repeat until the condition is met

Condition Types​

Function Condition​

You can use a function that returns a boolean:

workflow
  .step(incrementStep)
  .until(async ({ context }) => {
    const result = context.getStepResult<{ value: number }>("increment");
    return (result?.value ?? 0) >= 10; // Stop when value reaches or exceeds 10
  }, incrementStep)
  .then(finalStep);

Reference Condition​

You can use a reference-based condition with comparison operators:

workflow
  .step(incrementStep)
  .until(
    {
      ref: { step: incrementStep, path: "value" },
      query: { $gte: 10 }, // Stop when value is greater than or equal to 10
    },
    incrementStep,
  )
  .then(finalStep);

Comparison Operators​

When using reference-based conditions, you can use these comparison operators:

OperatorDescriptionExample
$eqEqual to{ $eq: 10 }
$neNot equal to{ $ne: 0 }
$gtGreater than{ $gt: 5 }
$gteGreater than or equal to{ $gte: 10 }
$ltLess than{ $lt: 20 }
$lteLess than or equal to{ $lte: 15 }

Returns​

workflow:

Workflow
The workflow instance for chaining

Example​

import { LegacyWorkflow, LegacyStep } from "@mastra/core/workflows/legacy";
import { z } from "zod";

// Create a step that increments a counter
const incrementStep = new LegacyStep({
  id: "increment",
  description: "Increments the counter by 1",
  outputSchema: z.object({
    value: z.number(),
  }),
  execute: async ({ context }) => {
    // Get current value from previous execution or start at 0
    const currentValue =
      context.getStepResult<{ value: number }>("increment")?.value ||
      context.getStepResult<{ startValue: number }>("trigger")?.startValue ||
      0;

    // Increment the value
    const value = currentValue + 1;
    console.log(`Incrementing to ${value}`);

    return { value };
  },
});

// Create a final step
const finalStep = new LegacyStep({
  id: "final",
  description: "Final step after loop completes",
  execute: async ({ context }) => {
    const finalValue = context.getStepResult<{ value: number }>(
      "increment",
    )?.value;
    console.log(`Loop completed with final value: ${finalValue}`);
    return { finalValue };
  },
});

// Create the workflow
const counterWorkflow = new LegacyWorkflow({
  name: "counter-workflow",
  triggerSchema: z.object({
    startValue: z.number(),
    targetValue: z.number(),
  }),
});

// Configure the workflow with an until loop
counterWorkflow
  .step(incrementStep)
  .until(async ({ context }) => {
    const targetValue = context.triggerData.targetValue;
    const currentValue =
      context.getStepResult<{ value: number }>("increment")?.value ?? 0;
    return currentValue >= targetValue;
  }, incrementStep)
  .then(finalStep)
  .commit();

// Execute the workflow
const run = counterWorkflow.createRun();
const result = await run.start({
  triggerData: { startValue: 0, targetValue: 5 },
});
// Will increment from 0 to 5, then stop and execute finalStep