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Available in Piebald Basic (Free) Piebald subagents allow the main agent to perform scoped sub-tasks such as exploring the codebase and make mechanical multi-file edits. It’s especially beneficial because it offloads context-heavy work like reading many files to a separate context window and returns only the distilled information requested, thus saving context window space in the main conversation.

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Subagents interface

When the model spawns a subagent, it’ll display as a normal tool call, but the tool call window will display a complete inline chat interface, allowing you to approve or deny any tool calls that the subagent makes. The inline view is intentionally minimal—you can only approve/deny tool calls. Everything else (editing, deleting, regenerating, etc.) requires opening the subagent chat in the main window. If you’d like to see the prompt that the model used for the subagent, you can hover over the “Prompt” text in the bottom-left corner of the subagent tool window. The subagent chat can be opened in the main window more easily using the “Open chat” button in the bottom-right corner of the subagent tool window. Once you’ve opened the subagent chat, you can then return to the main agent’s chat with the left-pointing arrow button up next to the chat title: subagent_back_button2.png Currently, next to the “Open chat” button, we display the permission mode used by that subagent, but in the future, we’ll enhance the subagent tool call window to display the provider, model, and profile too.

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Technical details

Subagents are spawned by a new builtin tool, LaunchSubagent. This tool takes a prompt parameter populated by the model. The last message generated by the subagent will be returned as the output of this tool back to the main agent. The LaunchSubagent tool creates a new chat and sends the prompt parameter as a first user message and automatically attaches a Subagent context notification that informs the subagent model that it’s running in a subagent context. Subagents are meant to execute focused tasks, so the following built-in tools are disabled for them:
  • LaunchSubagent
  • ProposePlanToUser
  • AskUserQuestion
  • TodoWrite
Since subagent chats are normal Piebald chats, you can work in the subagent chat like any other chat, even when the subagent is in progress. You can tag them, generate titles for them, etc. Subagent chats are highlighted green in the sidebar and are nested under their parent chat.

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Subagents are automatically approved

Since subagents function as extensions of the main agent, they’re automatically approved in all permission modes (Default, Auto-Accept, YOLO, and Plan). Because subagents are automatically approved, we’ve added settings for controlling the default provider, model, profile and permission mode for subagents in Settings → Built-in Tools.