Background Tasks — Ctrl+B and the /tasks System
Ctrl+B sends Claude's current work to the background so you keep your prompt while Claude keeps working. The /tasks system lets you monitor all running background tasks, check their status, and manage them without interrupting the work.
Quick Reference
- →Ctrl+B: background the current task — Claude continues working, prompt returns immediately
- →In tmux: press Ctrl+B twice (once for tmux, once for Claude Code)
- →/tasks: list all background tasks and their status
- →Ctrl+T: toggle the task list view
- →Ctrl+X Ctrl+K: kill all background agents (confirm within 3 seconds)
- →Auto-terminated at 5GB output or on session exit
- →Best for: long builds, slow test suites, parallel workstreams
What Background Tasks Are
When Claude is executing a long task — running a test suite, refactoring a large module, analyzing a codebase — Ctrl+B sends that work to the background. Your prompt returns immediately. Claude continues working. You can issue new prompts, start new sessions, or do other work while Claude finishes.
Background tasks inherit the permissions that were approved upfront for the session. They run concurrently with your main conversation. Output is written to files. You get a notification when the task completes.
If you are running Claude Code inside tmux, the first Ctrl+B is intercepted by tmux as its prefix key. Press Ctrl+B twice: the first for tmux (which doesn't match any tmux binding and passes through), the second for Claude Code.