---
id: background-jobs/a-commander-picks-the-cheapest-model-that-will
title: 'A commander picks the cheapest model that will do the job — for itself and for what it spawns'
theme: background-jobs
status: open
created: 2026-08-22
date_source: stated
order: 2
---

**Before it arms anything, a commander should weigh how hard the job actually is and say which model each
half should run on.** Wanted 2026-08-22, for later.

**Two models, not one**, and this is the part that makes it worth doing rather than a generic "use a cheaper
model" note. A commander has two quite different workloads:

- **the commander's own turns** — agreeing the job with the owner, writing a shell loop, reporting. Mostly
  conversation and one piece of bash.
- **the agent the loop SPAWNS when it fires** — which does the actual work, and whose difficulty is set by
  the job rather than by the conversation.

Those can differ by a lot in the same commander. The deploy commander is the worked example: its own turns
ran on Sonnet and were unremarkable, while the spawned agent judged six hosts, parsed a plan, decided what to
skip and wrote an honest report. A watcher that pings a URL and echoes the status needs neither to be clever.

**Inferred from the job, and SUGGESTED rather than imposed.** The commander proposes ("this looks like Haiku
for the watch and Sonnet for the action, because…") and the owner overrides. A model chosen silently is one
nobody can argue with, and the failure mode of choosing too small is not a slower answer — it is a watcher
that fires on the wrong condition, or an agent that half-finishes a deploy.

**Where it goes:** a section in the Commanders skill, beside the four shaping questions, since the moment to
ask it is the same moment — while the job is being agreed and before anything is armed. It is one more thing
to settle in the conversation the skill already describes.

**What would make it honest rather than a guess**, and the reason this is not urgent: nothing currently
measures whether the choice was right. The cost of a spawned agent is not recorded at all yet
(`command_hq_spawned.total_usd` exists and is always null), so a commander suggesting Haiku has no way to
learn it was wrong. Worth doing after cost accounting, or at least knowing that until then this is a
judgement with no feedback loop.