Build in Parallel

Documentation Index

Fetch the complete documentation index at: https://docs.replit.com/llms.txt

Use this file to discover all available pages before exploring further.

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What is the task system?

A task is a unit of work that Agent can plan and execute. Each task runs in its own thread — a separate conversation where Agent works independently. You can follow along, give feedback, or let it run in the background. The task system is how Agent breaks work into manageable chunks. When you describe what you want to build, Agent splits your request into discrete tasks and organizes them on a board with columns: Drafts, Active, Ready, and Done. Each task moves from left to right as it progresses, so you can see at a glance what’s planned, what Agent is working on, what’s ready for your review, and what’s finished. Background tasks queue automatically based on your plan, so work keeps moving without crowding your main thread. When a task is ready, you review the changes and apply them back to your main version — or dismiss them if they’re not what you wanted.

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How background tasks work

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Task states

Every task goes through a series of stages: from an idea to part of your app. Each stage has its own icon so you can tell what’s happening at a glance.

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The task board

All your tasks live on a board organized into columns. Here’s how the board looks as tasks move through each stage.

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Drafts and Active

When you describe what you want to build, Agent creates draft tasks — each with a title, description, and a step-by-step plan. You can review the plan, ask Agent to adjust it, or accept it as-is. Once you accept, tasks move to the Active column and Agent starts building them. Each task runs in its own isolated copy of your project, so nothing changes in your main version until you say so. Some tasks depend on others — for example, a task that builds a dashboard needs the database to be set up first. These tasks wait as queued until their dependencies finish. Tasks also queue if you’ve reached your plan’s limit for active background tasks.

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Ready and Done

When a task finishes building, it moves to Ready. This means the work is complete, but nothing has changed in your main version yet — you’re in control. You can apply changes in two ways:

• From the thread — Open the task’s thread and you’ll see a review prompt like the one below. Press Apply changes to main version to bring the work into your project, or Dismiss to discard it.

• From the board — Click the three-dot menu on any Ready task card to see your options, then press Apply changes

Once applied, the task card moves to the Done column. Agent handles conflicts automatically when you apply changes from multiple tasks. If something doesn’t look right, you can always ask Agent to fix it.

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Archiving and cancelling tasks

You can stop a task at any point in its lifecycle, but the option you see depends on where the task is on the board. Both Archive and Cancel move a task to the Done column, but they behave differently: In short: archive is for planning sessions you want to circle back on later, and cancel is the permanent stop button for tasks that are queued, already running, or finished building. You can find both archived planning sessions and cancelled tasks in the Done column on the far right of the task board, alongside completed tasks.

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Follow-up task suggestions

After you apply a task, Agent looks at the full context of your project and suggests follow-up tasks you might want next. These appear as inline rows right under the finished task in the Done column, so you can keep building without leaving your flow. Follow-up suggestions typically cover:

• New features to build — capabilities that pair naturally with what you just shipped
• Performance improvements — optimizations Agent noticed while working on the task
• User experience enhancements — polish and refinements that round out the feature

Review each suggestion, select Accept on the ones you want, and Agent sends them to the background. Rejected suggestions stay out of your way. You can hide all suggestions with Hide suggested tasks in the Done column header and bring them back later — a small badge on the parent task tells you how many follow-ups are hidden.

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What you can build

The task system works for any project. Here are a few patterns where it shines:

• Ship large features in smaller pieces — Split authentication, a dashboard, and an API layer into separate tasks so Agent can work through them cleanly
• Plan complex projects — Break a large feature into well-scoped tasks with dependencies, then execute with confidence
• Compare different design directions — Use separate tasks to try multiple UI approaches, then pick the best result

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Frequently asked questions

Do I need to change how I build?

No. The main thread works exactly the same. Agent automatically creates tasks behind the scenes when it helps. You can also use Plan mode to see and manage tasks explicitly.

Why are my tasks running one at a time?

Core runs 1 background task at a time. Pro supports up to 10 concurrent background tasks. Once you hit your plan’s limit, additional tasks queue and start as slots open up.

How does Agent handle conflicts when applying background tasks?

Agent uses AI-assisted conflict resolution. It understands what each task was trying to accomplish and applies the changes intelligently. If something looks off, you can ask Agent to fix it in the thread.

Can tasks depend on each other?

Yes. Agent automatically detects dependencies — for example, a task that builds a dashboard depends on the task that creates the database schema. Dependent tasks wait until their prerequisites complete.

What's the difference between archiving and cancelling a task?

Archive applies to planning sessions — drafts that haven’t started building yet. Archived planning sessions are preserved and can be restored from the Done column.Cancel applies to tasks that have already moved from planning into building. Cancelling stops the task and discards its work, and cancelled tasks can’t be restored — you’d need to start a new task instead.

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Availability