metautil

const (
	// MaxMetadataKeys is the maximum number of key-value pairs in a metadata
	// map. Typical kernel entries carry 3-10 keys (trace_id, request_id,
	// correlation_id plus domain context); 64 provides 6x headroom while
	// keeping serialized overhead under 1 KB for small entries. OTel allows
	// 128 attributes/span.
	MaxMetadataKeys = 64

	// MaxMetadataKeyLen is the maximum byte length of a single metadata key.
	// Measured in bytes (len()), not runes -- multi-byte UTF-8 keys are
	// counted by their wire size, consistent with transport-level limits.
	MaxMetadataKeyLen = 256

	// MaxMetadataValueLen is the maximum byte length of a single metadata
	// value. Aligned with NATS MAX_CONTROL_LINE_SIZE (4096). Measured in
	// bytes.
	MaxMetadataValueLen = 4096

	// MaxMetadataTotalSize is the maximum total byte size of all metadata
	// key-value pairs combined (sum of len(k)+len(v) for each pair).
	MaxMetadataTotalSize = 65536

	// DomainOutbox / DomainCommand are the only valid domainPrefix values
	// accepted by ValidateLimits. Adding a third transport requires extending
	// these constants AND every per-error helper switch below.
	DomainOutbox  = "outbox"
	DomainCommand = "command"
)