# Lineage enforcement

The Lineage Firewall tracks execution provenance per `sessionId`. When lineage is **contaminated** (e.g. external injection), destructive tools are blocked at the sidecar.

## Failure modes

| `BLEKLINE_FAILURE_MODE` | Behavior |
|-------------------------|----------|
| `block` (production default) | Parser/lineage errors → deny |
| `passthrough_with_alert` | Allow traffic; emit `governance_degraded` audit (staging only) |

Never default `passthrough_with_alert` in production Helm values.

## Destructive tools (v1)

Includes `delete_file`, `execute_shell`, `send_email`, `write_file`, and similar — configurable in enterprise program.

## Test contamination (pilot)

```bash
curl -X POST http://127.0.0.1:8787/v1/lineage/contaminate \
  -H "Authorization: Bearer $BLEKLINE_SIDECAR_AUTH" \
  -H "Content-Type: application/json" \
  -d '{"sessionId":"pilot-1","detail":"injection drill"}'
```

Subsequent `delete_file` enforce on `sessionId=pilot-1` returns `action: block`.

## Status

**Shipped v1** — sidecar `0.2.0-nhim`.