mesh-grants' sealed grants and the controller's merge record each met "message size exceeds maximum" (JetStream
10054) only after the put, and a writer that retries looped on a value that can never land; an update over the
limit was even answered as a revision mismatch, which every compare-and-set writer retries.
Quick fix: cap the two values in their modules. Thorough fix, chosen because the kind was met twice and every
module writes through the SDK: the package kvlimit checks a value against its bucket's largest message (read from
its stream and kept) before the put, naming the bucket, the key, the size and the limit, and turns the bus's own
refusal into the same *TooLarge (errors.Is kvlimit.ErrTooLarge), so no writer retries it. The SDK's own writers
use it: process.State (Put, Create, CreateTTL, Update), process.AwaitedBucket, the runtime state of a bundle
(stdio KeptState, against the module state's 256 KiB) and mesh-hand-compose. A value that can outgrow its bucket
is split over keys or kept in the object store with its name in the key.
Since the grants part creates a manifest's buckets after a delivery (ADR 0547), a module restarted by that
delivery can open a new state before it exists; OptionalBucket answered nil and the part never looked again
(mesh-delivery's checker and builder, state hearing, 2026-10-26). AwaitBucket binds on the server's
STREAM.CREATED advisory, or at the next use, and writes the latest value kept per key. The copied composer's
agreement test leaves that one row out: the controller's list is no longer loaded since the take-over.
jschoubben
jochen