A claim may name the verbs it serves for its seat (hq ADR 0160)

The store's databases is not postgres's postgres_list_databases, and a holder may serve both. A
claim's serves names the seat's verbs the module implements for the role; absent, the module's own
tools must list every verb the seat promises, which is how a module named like its seat says they
are one and the same. Registration refuses a claim naming a verb the seat never promised, and the
credential's claims carry the claim's own verbs to the runtime.

internal/catalogue/verbs.go

@@ -133,7 +133,22 @@ func schema(properties map[string]string, required []string) map[string]any {
 	return out
 }
 
-// unservedVerbs is what a seat promises and a claimant's `tools` does not answer.
+// unpromised is what a claim says it serves and the seat's protocol never promised.
+func unpromised(serves []string, promised []Verb) []string {
+	has := map[string]bool{}
+	for _, v := range promised {
+		has[v.Name] = true
+	}
+	var extra []string
+	for _, s := range serves {
+		if !has[s] {
+			extra = append(extra, s)
+		}
+	}
+	return extra
+}
+
+// unservedVerbs is what a seat promises and a claimant's offer for it does not answer.
 func unservedVerbs(tools []string, promised []Verb) []string {
 	has := map[string]bool{}
 	for _, t := range tools {