# Cost Management Rules — propane-will-491900-m5

## Hard rules
1. **Billing budget alert** must be created BEFORE any resource deployment.
   Alert thresholds: 50% / 75% / 90% / 100% of monthly budget.
   Start with 5 USD (~55 NOK) for dev/test phases.
2. **Agent Runtimes** cost money when deployed — always undeploy via `03-teardown.sh` at end of workday.
3. **Vertex AI Endpoints** — same rule as above.
4. **Staging bucket lifecycle**: auto-delete objects older than 7 days.
5. **Colab Enterprise runtimes** — terminate when not actively developing.
6. GCP does NOT enforce a hard spend cap. Budget alerts are email-only by default.

## Agent Runtime pricing (May 2026)
| Resource | Free Tier/month | Paid rate |
|---|---|---|
| vCPU | 180,000 vCPU-seconds | ~$0.0864/vCPU-hour |
| RAM | 360,000 GiB-seconds | ~$0.0090/GiB-hour |

Agent Runtime does NOT bill for idle/non-running agents (pay-per-use). Always delete at end of session.

## NEW billing lines (effective Jan 28, 2026)
These were previously free/in preview and are now METERED:
- **Sessions** — agent interaction contexts
- **Memory Bank** — long-term memory storage
- **Code Execution** — sandboxed code runs

→ Trim session histories. Only persist high-value facts to Memory Bank. Disable Code Execution on agents that don't need it.

## Cloud Run cost profile
- `--min-instances=0` → scales to zero — no idle cost (use for dev/test)
- `--min-instances=1` → keeps one warm instance — eliminates cold-start (~$4–8/month)
- Cleanup: `gcloud run services delete SERVICE_NAME --region=us-central1 --quiet`

## Lifecycle JSON for staging bucket
```json
{
  "rule": [
    {
      "action": { "type": "Delete" },
      "condition": { "age": 7 }
    }
  ]
}
```
```bash
gcloud storage buckets update gs://propane-will-491900-m5-agent-staging \
  --lifecycle-file=lifecycle.json
```

## RAG Engine cost warning
- If RAG Engine uses a managed Spanner instance as vector DB → billed 24/7.
- For dev/test: prefer `us-east1` or `us-east4` until us-central1 allowlist is granted.
- Contact: `vertex-ai-rag-engine-support@google.com` for us-central1 allowlist access.

## Artifact Registry cleanup
```bash
gcloud artifacts docker images list \
  us-central1-docker.pkg.dev/propane-will-491900-m5/oavauco-docker \
  --format="value(IMAGE,DIGEST)" | tail -n +2 | \
  while read -r image digest; do
    gcloud artifacts docker images delete "${image}@${digest}" --quiet
  done
```

## Pub/Sub hard-stop billing automation (optional)
Consider: Pub/Sub → Cloud Run Function to auto-disable billing if budget alert fires.
Template: https://cloud.google.com/billing/docs/how-to/notify#cap_disable_billing_to_stop_usage