Retiring a field

ac drift tells you that removing amount breaks three consumers. The next question takes weeks: when can you remove it? ac retire answers it from the evidence you already have, and the company site tracks every retirement under way.

Ask

ac retire payments/payment.completed amount \
  --catalog https://catalog.example.com/catalog.json \
  --snapshot .autotel/snapshot.json \
  --pacts https://pact-broker.example.com --pact-token-env PACT_BROKER_TOKEN

## Removing `amount` from payments/payment.completed: blocked

- **LedgerService**: needs it. reads amount (payments-service); pact expects amount; failed verification against 9.1.0 (Pact Broker)
- **FraudService**: unknown. seen receiving the event (snapshot of 2026-10-01)
- **AuditService**: unspecified. declares no fields it reads (company index, default branches as of 2026-10-19)
- **BillingService**: clear. reads paymentId, not amount (payments-service)

Producer: still sent (snapshot of 2026-10-01).

Next: LedgerService moves off amount. Find out whether FraudService needs amount: it receives the event and declares nothing. AuditService declares the fields it reads, in autocatalog.consumes.json.

Leave out the field to ask about the whole event. The command exits 0 when every consumer is clear and 1 otherwise, so a pull request that removes the field can gate on it.

Where each consumer stands

Standing	Means	Blocks
Needs it	a declaration or a pact says it reads the field	yes
Unknown	a snapshot saw it receive the event, and nothing declares it a consumer	yes
Unspecified	it declares that it consumes the event, but not which fields it reads	yes
Clear	it declares the fields it reads, or its pact shows them, and this is not one	no

Silence never clears a consumer. A source that names fields outranks one that does not, so a pact settles a consumer that only declared the event. When two sources that name fields disagree, the one that says it needs the field wins.

The evidence

• The event’s own consumers, from its manifest: consumers and consumerFields.
• Other repositories’ declarations, from the company site’s /catalog.json with --catalog. These are what each repository’s default branch declares as of the site’s last build, which the output dates. A declaration says what the code on that branch reads, not what is deployed. A consumer’s own autocatalog.consumes.json counts beside what the producer wrote down for it, so a consumer that says it reads the field needs it.
• A runtime snapshot, with --snapshot: who was seen receiving the event, and whether the producer still sends the field.
• Pacts, with --pacts: a pact file, a folder of them, or a Pact Broker’s base URL. A message counts when its description names the event, as payment.completed or PaymentCompleted. From a broker, each consumer’s latest pact with the provider (--pact-provider, by default the event’s first producer) and its latest verification come along. The broker is the place that knows which consumer versions are deployed; ac retire reports its verification as it found it. Pacts it could not read block the verdict: a broker that cannot be reached, a file that is not a pact, a message body that is encoded or not JSON, a link off the broker, more than 200 pacts, or no pact with a message for the event. The output lists them under missing evidence.

Track it on the site

Mark the field deprecated: true in its schema, or the whole event status: deprecated. The company site’s Retirements page then lists each one with where its consumers stand, from every repository’s declarations and snapshots, as of each build.

Then remove it

When every consumer is clear, remove the field and bump the event’s major version. ac drift reports the removal as breaking, acknowledged by the major version, and names who to tell.