Mastra workflows have suspend/resume functionality enabling to wait for humans in the loop. That works in playground now!
Here’s a demo:
We also shipped an API for automatically closing streams when a workflow suspends, allowing them to be resumed later
resumeStream
The default behavior of suspend() is to leave the stream open. We shipped a closeOnSuspend option to close a stream automatically when a workflow suspends.
Now, when you’re ready to resume, use resumeStream to pick up your stream exactly where the workflow left off.
As an example:
1// 1. Initial execution with closeOnSuspend enabled
2const run = await workflow.createRunAsync();
3const output = run.stream({
4 inputData: { task: "approval_needed" },
5 closeOnSuspend: true, // 🔑 Stream will close when workflow suspends
6});
7
8// Stream events until suspension
9for await (const chunk of stream.fullStream) {
10 console.log(chunk.type, chunk.payload);
11 // Stream automatically closes when workflow suspends
12}
13
14const result = await stream.result;
15console.log(result.status); // 'suspended'
16
17// --- Time passes, user provides input ---
18
19// 2. Resume and get a NEW stream for the continuation
20const resumedOutput = await run.resumeStream({
21 resumeData: { userInput: "approved" },
22 step: "approval-step", // Optional - auto-detected if omitted
23});
24
25// Stream remaining events from the new stream
26for await (const chunk of resumedStream.fullStream) {
27 console.log("Resumed:", chunk.type, chunk.payload);
28}
29
30const finalResult = await resumedStream.result;
31console.log(finalResult.status); // 'success' or 'failed'We hope this helps you build more human-in-the-loop workflows in Mastra. Happy building! 🚀
