The probe returned `error: undefined` on a dimension match. `undefined` is not a
JSON value -- JSON.stringify silently drops it from an object -- so the shape
looked harmless and was not: the harness enforces the declared output schema
against the canonical value before materialising it, and an explicit undefined
property fails that check. A perfectly healthy status call could not be returned
at all.
Fixed at the boundary rather than at each site. Every return now funnels through
`toJsonValue`, which drops undefined properties exactly as JSON.stringify would,
maps non-finite numbers to null (same reasoning: JSON.stringify(NaN) is "null"),
turns an undefined array slot into null rather than shifting indices, and refuses
a circular value instead of recursing forever. `update` was carrying
`errorCode: undefined` and `ensureSlopo` a `detail: undefined` on the same path,
so a per-site fix would have left two more of these waiting.
The probe also now omits `error` rather than assigning undefined, since it is a
plausible thing for another consumer to read.
Four regression tests, and they were checked against a negative control: with the
sanitiser reverted and the undefined restored, exactly the "probe SUCCEEDS" test
fails with "does not survive a JSON round trip" and the others still pass, which
is what makes it a test of this bug rather than of the JSON round trip in
general.
dsh-slopo agent
46124b11aa