`stream:camera_frames` and `channel:print_alerts` are the only interface
between `continuum-backend` and `continuum-ai-worker`, and there was
nothing specifying either. They had drifted completely: the backend
wrote `farmId`, `printerId`, `r2ObjectKey` and `capturedAt`; the worker
read a single field called `printer_id` and ignored the rest. Every task
was delivered, acknowledged, and attributed to a printer called
"unknown" - and nothing errored, because a stream entry is a flat string
map and asking it for a field that is not there is not a failure. Same
shape as the /ws/edge/v1 drift, found the same way.
`schemas/continuum/v1/ai/` is now canonical, with a TypeBox mirror in
ts-types and a Rust mirror in the worker.
Two things the schemas have to say that JSON Schema does not naturally
express, both of which caused real bugs:
- A Valkey stream entry is a flat field/value map of *strings*. No
nesting, no numbers, no null. So FrameTask has no numeric or nested
properties, and a field with no value is omitted from the XADD rather
than written as `""` - an empty string is a value, and the producer
was writing one for `print_job_id`, which a consumer would carry into
a lookup or a uuid column.
- PrintAlert, by contrast, *is* a JSON document, because PUBLISH carries
one opaque string. It is also fire-and-forget with no persistence, so
it can only ever be a live-console feed and never the record of a
detection.
The README's layout section was stale (it still listed four DTOs that
were removed in 2026-09) and did not mention `edge/` or `ai/` at all. It
now names both, says why the inter-service protocols live here, and
notes that their Rust mirrors sit in the single repo that consumes each
rather than in `packages/rust-types`.
octoturge
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