# `mix llm_db.history.backfill`
[🔗](https://github.com/agentjido/llm_db/blob/main/lib/mix/tasks/llm_db.history.backfill.ex#L1)

> #### Deprecated {: .warning}
>
> This legacy task remains callable for compatibility. Seed snapshot-based
> history once with `mix llm_db.history.migrate_git --publish`, then use
> `mix llm_db.history.rebuild --publish`. Removal may occur no earlier than
> `v2027.0.0`, after at least one minor release deprecation window.

Backfills model history from committed provider snapshots using the legacy
Git-to-NDJSON implementation.

The task walks git history for `priv/llm_db/providers/*.json`, computes model
deltas per commit, and writes append-only history artifacts:

- `priv/llm_db/history/events/YYYY.ndjson`
- `priv/llm_db/history/snapshots.ndjson`
- `priv/llm_db/history/meta.json`

## Usage

    mix llm_db.history.backfill
    mix llm_db.history.backfill --force
    mix llm_db.history.backfill --from <sha>
    mix llm_db.history.backfill --to <ref>
    mix llm_db.history.backfill --output-dir priv/llm_db/history

## Options

- `--force` - Remove existing generated history files first
- `--from` - Start commit SHA/ref (inclusive)
- `--to` - End commit SHA/ref (default: `HEAD`)
- `--output-dir` - Directory for generated history files (default: `priv/llm_db/history`)

---

*Consult [api-reference.md](api-reference.md) for complete listing*