Trace an invoice into quarantine¶

In this tutorial, we will follow INV-0105, a synthetic invoice that names a service which does not exist. We will see the source row, its deterministic classification, and its quarantine row.

Build the invoice path¶

The project tags invoice resolution as layer2_invoices and raw rejections as quarantine. Include their upstream dependencies with the leading + selectors:

uv run dbt build --select "+tag:layer2 +tag:quarantine"

This builds the mapping and service inputs needed to classify invoices consistently.

Inspect the source invoice¶

uv run dbt show --inline "
select
    invoice_id,
    customer_ssn,
    service_id,
    issued_date,
    due_date,
    is_paid
from {{ ref('stg_invoices') }}
where invoice_id = 'INV-0105'
" --limit 10

The row refers to SVC-7777-A. That service ID does not appear in the checked-in customer_services seed.

Ask the classifier for its decision¶

int_invoice_resolution is an ephemeral model. dbt expands it into the query rather than creating a permanent relation.

uv run dbt show --inline "
select invoice_id, resolution_status
from {{ ref('int_invoice_resolution') }}
where invoice_id = 'INV-0105'
" --limit 10

The expected status is:

SERVICE_NOT_FOUND

The classifier evaluates its rules in a fixed order. For this row, the customer exists, but no source service period has the requested service key.

Find the quarantine record¶

uv run dbt show --inline "
select
    invoice_id,
    service_id,
    quarantine_reason,
    quarantined_at
from {{ ref('quarantine_invoices') }}
where invoice_id = 'INV-0105'
" --limit 10

You should see one row with quarantine_reason = SERVICE_NOT_FOUND.

Now verify that the same invoice did not enter protected Layer2:

uv run dbt show --inline "
select count(*) as accepted_rows
from {{ ref('int_invoices_resolved') }}
where invoice_id = 'INV-0105'
" --limit 1

The result is 0.

What you have observed¶

The source row was preserved, classified with a stable reason, excluded from protected analytics, and made available for controlled remediation. It was not silently dropped.

Next, observe terminal deletion.

Read Quarantine instead of silent dropping for the design rationale. The exact Layer1 relations belong in the source and Layer1 reference.