Operation identity example

Canonical input identity is a useful small SDK example before writing an adapter:

from skulk_capability_sdk.operations import input_digest

intent = {"prompt": "A fox crossing a snowy field", "seconds": 5}
reordered = {"seconds": 5, "prompt": "A fox crossing a snowy field"}
changed = {"prompt": "A fox crossing a snowy field", "seconds": 8}

assert input_digest("example-node:render@1.0.0", intent) == input_digest("example-node:render@1.0.0", reordered)
assert input_digest("example-node:render@1.0.0", intent) != input_digest("example-node:render@1.0.0", changed)

This verifies canonical digest behavior, not durable operation admission. An installed node, descriptor and operation id also scope the journal record. An input digest is not permission to launch work.

Apply it to an application

Keep the same operation id when retrying the same intent after a lost response. Reject an id reused with a changed intent. Persist the backend reference when a job is accepted. After restart, reconcile that reference before deciding whether a new submission is safe.

Follow the durable job guide, then Video Studio’s render lifecycle to see this rule across a real model job. Do not replace the operation service with an in-memory dictionary if you need restart safety.