Agent guidelines

Coriolis migrates VMs between clouds. Cloud support lives in separate provider plugins (often private). Target Python 3.10 and 3.12.

Coriolis terminology

Minion: temporary worker VM for disk transfer and os-morphing (guest prep: network, packages, drivers). Minion pools reuse them. Some source providers skip minions and read disks directly.
Transfer: creates destination volumes and copies disk data. Re-run a transfer as a new execution to pick up later changes. Most providers can do that incrementally.
Deployment: creates the destination VM from a completed transfer.
Replica vs migration (transfer.scenario: replica / live_migration) is a licensing split, not two engines. Replicas can be re-executed and re-deployed even after license fulfillment.

Users configure source/destination endpoints (credentials) and environment options (transfer and resulting VM settings).

Use .tox/py3/bin/ (stestr, ruff); it has project deps. Ignore .mypy_cache, .ruff_cache, .tox.
Follow ruff (tox.ini, ruff.toml).
Prefer f-strings over % formatting and str.format in new or touched code.
Public methods need docstrings (subclasses may inherit). Use type hints when the type is known.
Do not add helpers for trivial checks such as server.power_status == "RUNNING"; keep those inline.
Do not strip still-relevant inline comments.
If regenerating a file, replace its contents; do not append duplicates.
Empty __init__.py files must not have license headers.

Prefer @mock.patch / @mock.patch.object over with mock.patch.
For multiple mock calls, use assert_has_calls. For a single call, assert_called_once_with is fine. Match nearby tests.
Integration tests use Docker providers; external cloud providers are optional.