When a tool call includes "background": true, it executes via
proc/new.bg and returns immediately with a PID in a
<system-proc-background> tag. The agent tracks active background
processes and injects their output as <system-proc-interrupt> blocks
alongside subsequent tool results.
The model sees background updates without polling. It can react to
build failures, log events, etc. naturally. Kill via PID when done.
Implementation:
- toolsrv client: CallToolBackground (uses proc/new.bg as rdwr)
- toolsrv: proc/new.bg upgraded from write-only to request-response
- agent: bgTracker collects last 20 lines of output per proc
- agent loop: injects interrupts after execToolCalls, before h.update
- system prompt: documents the background mechanism and rules
Ollie Agent
Levi Neely