Carry a channel's capabilities on its claim and tell the router every kind, so an answer is judged by the controller's record and not the channel's word

internal/catalogue/seats_declared.go

@@ -2,6 +2,7 @@ package catalogue
 
 import (
 	"fmt"
+	"regexp"
 	"sort"
 	"strings"
 )
@@ -331,9 +332,43 @@ func CatalogueProblems(shelf Shelf) []string {
 	return problems
 }
 
+// ChannelCapabilities is the fixed vocabulary `channel-capabilities/1` (novox/hq ADR 0234 §2): a word
+// outside it is refused. `max-length:<N>` takes a number.
+var ChannelCapabilities = map[string]bool{
+	"deliver": true, "reaches-away": true, "loud": true, "silent": true, "edit": true,
+	"reaches-when-mesh-down": true, "private": true,
+	"choice": true, "reply": true, "threads": true, "operator-first": true,
+	"verified-sender": true, "exact-render": true, "code-factor": true, "key-factor": true,
+}
+
+var maxLength = regexp.MustCompile(`^max-length:[1-9][0-9]{0,6}$`)
+
+// capabilityProblems are the words of a claim outside the vocabulary, and capabilities on a claim of a
+// seat that is not kinded.
+func capabilityProblems(module string, c Claim, kinded bool) []string {
+	if len(c.Capabilities) == 0 {
+		return nil
+	}
+	if !kinded {
+		return []string{fmt.Sprintf("%s claims %s with capabilities, and only a kinded bench's claim carries them",
+			module, c.Name)}
+	}
+	var problems []string
+	for _, w := range c.Capabilities {
+		if !ChannelCapabilities[w] && !maxLength.MatchString(w) {
+			problems = append(problems, fmt.Sprintf(
+				"%s claims %s with the capability %q, which channel-capabilities/1 does not have", module, c.Name, w))
+		}
+	}
+	return problems
+}
+
 // kindProblems is a claim judged against a declared seat's kind: a kinded bench takes one claim per kind,
 // a usable name; any other seat takes none.
 func kindProblems(module string, c Claim, s SeatDeclaration, taken map[string]string) []string {
+	if problems := capabilityProblems(module, c, s.Kinded); len(problems) > 0 {
+		return problems
+	}
 	switch {
 	case !s.Kinded && c.Kind != "":
 		return []string{fmt.Sprintf("%s claims %s of kind %q, and only a kinded bench takes a kind",