The brand under which an errorHandler middleware function carries its
resolved IErrorResponder.
Created with Symbol.for, not Symbol(), so two copies of this package in
one process resolve the same key — the same failure mode UPGRADE_INTENT guards against. The brand is the kernel's only route to the
resolved formatter: the drain 503, the malformed-request 400, and the
request-lifecycle hooks all run BEFORE the pipeline, where
errorHandler's ctx.state publication cannot reach them, and the kernel
may not import @setu-ts/exceptions (AI_GUIDELINES §2.2). The kernel reads
the brand off the compiled pipeline at startup and seeds the responder into
the state those sites hand to respondWithError.
The property is written non-enumerable and is an implementation detail of the
seam — not part of the MiddlewareFunction contract.
The brand under which an
errorHandlermiddleware function carries its resolvedIErrorResponder.Created with
Symbol.for, notSymbol(), so two copies of this package in one process resolve the same key — the same failure modeUPGRADE_INTENTguards against. The brand is the kernel's only route to the resolved formatter: the drain503, the malformed-request400, and the request-lifecycle hooks all run BEFORE the pipeline, whereerrorHandler'sctx.statepublication cannot reach them, and the kernel may not import@setu-ts/exceptions(AI_GUIDELINES §2.2). The kernel reads the brand off the compiled pipeline at startup and seeds the responder into the state those sites hand torespondWithError.The property is written non-enumerable and is an implementation detail of the seam — not part of the
MiddlewareFunctioncontract.