Cancel Control Plugin

Coordinates cancellation of in-progress agent operations. Tracks active turns and routes cancellation requests to the appropriate handlers.

Details


ID	`nexus.control.cancel`
Dependencies	None

Events

Subscribes To

Event	Priority	Purpose
`agent.turn.start`	10	Tracks which turn is active
`agent.turn.end`	10	Clears active turn tracking
`cancel.request`	10	Receives cancellation requests from I/O
`cancel.resume`	10	Receives resume requests

Emits

Event	When
`cancel.active`	Broadcasts cancellation to all handlers
`io.status`	Status updates

How It Works

When the user triggers a cancel (e.g., pressing a key in the TUI), the I/O plugin emits cancel.request
The cancel controller checks if there’s an active turn
If so, it emits cancel.active with the turn ID
All plugins listening for cancel.active abort their current work (LLM provider cancels the API call, agent stops iterating)
When the user resumes, cancel.resume restarts the flow

Include this plugin when using agents that support cancellation (ReAct, Plan & Execute, Orchestrator). It’s essential for interactive workflows where the user may want to interrupt long-running operations.

plugins:
  active:
    - nexus.control.cancel
    # ... other plugins

Nexus Documentation