Experiment 50: the operator machine's second live run

[usirin]

The second live run of the operator machine, on kamp-us/demlik#625, a small code bug picked because its first build might fail review.

It did fail review, and the machine repaired and merged it (PR 628): 40.2 minutes, $7.68, no operator agent, no person, nothing done by hand. It also wasted a quarter of that money: three builders in a row were recorded dead after doing their work.

The write-up is experiment 50.

Before the run

• The lane's read names the pull request, and every read and write that needs it takes it from there.
• A wait for checks before a review has a time limit. Past it the run stops.
• A question nobody answers ends the run parked, with the working copy removed and the lane released. The question is named by the park, not by the run, so a later run finds it and reads the replies since.

What the run showed

• The repair loop needed no new code. A failed review folds the lane back to build, and the routing table sends build to a builder whatever round it is.
• Three builders left early. Each ran its wait on CI as a background command and ended its turn. An SDK session ends with its main agent's turn, so the report to the lane never ran. The machine recorded a dead shell and started another, three times, until CI finished. Cost: $1.94 and 236k tokens.
• The Check refused two harmless commands (a redirect to /dev/null inside a subshell, one to /dev/stdout).

Fixed here

• The Check refuses a background command and says why; the shell's prompt says it too.
• The Check no longer takes a device or a bracketed path for a write outside the working copy.
• The field rows say why a shell was recorded dead.

Cost, beside the other lanes

	#600 (agent)	#601 (agent)	#559 (machine)	#625 (machine)
Driver, tokens	115,872	119,072	0	0
Lane total	436,573	373,465	152,432	656,676
Shell runs	3	3	3	8
Minutes	33.8	31.3	18.8	40.2
Dollars	not recorded	not recorded	$1.74	$7.68

#625 is the only one that needed a repair. Without the three early leavers it comes to 420,502 tokens and $5.74.

Not tested yet

The merge-queue Listen, a park, a question to a person, a shell stopped for time or money, a restart, two lanes at once.

State

• pnpm typecheck: green.
• pnpm test: 403 passed.

🤖 Generated with Claude Code