Ask the agent to delegate independent parts of your task to subagents. Each subagent works in a separate conversation and reports back to the agent in your original thread, called the parent thread.
When to use subagents
Use subagents for independent work that can happen alongside the main task, such as investigating separate parts of a codebase, implementing independent parts of a change, or getting another agent to check an existing change.
Ask the agent to use subagents and describe the work you want delegated. When delegation is set to Enabled, the agent can also choose to use them without being asked. To require an explicit request, select Only When Asked in Settings > Subagents > Enable Sub-agents.
Keep tightly dependent steps in the main thread when the next step needs the result of the previous one. Delegating that work adds a handoff rather than letting tasks run in parallel.
Profiles
A profile describes a subagent’s role and chooses its model. Delta includes three profiles:
- Worker implements changes with full tool access.
- Scout gathers information from the codebase or the web.
- Reviewer checks existing changes.
Delta selects default models for these profiles. You can change each profile’s model and thinking effort in Settings > Subagents. See Agent profiles settings for model choices and adding custom profiles.
Access to your files
By default, Worker and Reviewer subagents use isolated copies of the parent’s Delta worktrees. Their changes merge back automatically on successful completion. Failed isolated work does not merge back. Scout uses the parent’s checkout directly, so its edits take effect immediately.
You can change a profile’s worktree mode in its TOML file. See Agent profiles settings.
Scout and Reviewer do not have file-editing tools, but both can change files through terminal commands. Don’t treat either profile as read-only. A Scout’s terminal commands can affect the parent’s checkout while the main agent is still working.
Follow their work
Each subagent appears nested under its parent in the thread sidebar. Open it to read its conversation and check its status, such as Queued, Running, Waiting to sync, or Failed. If it fails, open it to see the error.
Messages between agents appear as folded Sent Agent Message and Received Agent Message events; expand an event to read the message. Agents can also message another thread. The parent receives the subagent’s final result automatically. Ask the parent to send a follow-up message if you need to redirect the work.
Press Cmd+F on macOS or Ctrl+F on Linux and Windows to search the focused
subagent conversation. Press Escape there to stop that subagent.
In the desktop sidebar filter, use Subthreads > Subagents to show or hide subagents alongside Plain, Reviews, and Land children. An expanded parent shows the six newest matching children across these kinds. Choose Show N more to reveal the rest.
Click a subagent to open it as primary, or hold Cmd on macOS or Ctrl
on Linux and Windows while clicking to open it in a tab.
On desktop and web, View All Subthreads (Cmd+J on macOS or Ctrl+J
on Linux and Windows) opens a picker for the parent’s children. Filter by
kind, and press Tab to show or hide archived children.
Models and configuration
In Settings > Subagents, choose each profile’s default model and thinking effort. To use a different model for a particular provider, open that provider’s Model Preferences in LLM Providers.
Delta checks for model choices in this order:
- Your provider-specific model choice.
- Your default model choice for the profile.
- Delta’s built-in default.
If you haven’t set a choice, Delta moves to the next option. Worker defaults to the parent’s model. With ChatGPT sign-in, your plan affects the built-in Scout and Reviewer defaults; explicit profile model choices take precedence.
Use Subagents settings to control delegation, concurrency limits, and whether the parent can override the profile’s model choice.
What’s next
- Settings covers delegation controls and custom profiles.
- Models & Providers covers connecting providers and choosing models.
- Review & Sync Changes covers reviewing the resulting changes and bringing them into your repository.