# Local Overlay (`config/config.local.yaml`)

`config.local.yaml` is a gitignored, deep-merged overlay on top of the
tracked `config/config.yaml`.  Anything placed in the overlay takes
precedence when `load_config()` merges the two files — the overlay only
needs the keys you want to change; everything else falls through to the
base.

## What belongs in the overlay

Values that are specific to your machine or deployment and would turn
`config/config.yaml` dirty if tracked:

- `local_energy.enabled` + `local_energy.tariff_usd_per_kwh` — metering
  per-machine, tariff often differs between sites.
- `classifier.base_url` / `verification.base_url` — Ollama may live on a
  different host or VPN address on each box.
- Any tuning knob you change between machines (`num_ctx` overrides,
  per-host profile tweaks).

## What does NOT belong here

**Secrets.**  Secrets (`NEURALWATT_API_KEY`, etc.) stay in `.env`.  The
overlay is YAML loaded as configuration, not as a credential store.

## A dirty `config/config.yaml` is a smell

If your working copy of `config/config.yaml` is modified, someone edited
the shared defaults by hand.  Move those edits into a new entry in
`config.local.yaml` — the base file should stay clean enough to commit
and share.

See `config/config.local.yaml.example` for concrete key examples.