A module's trusted list of callers in the SDK, so the vault's secret-ask answers the callers its manifest names as the runtime proved them (issue 774, ADR 0563 §8)

go/caller_test.go

@@ -75,6 +75,21 @@ func TestACallerInTheArgumentsIsNeverTheCaller(t *testing.T) {
 	if got != "shanks.node-tools" {
 		t.Fatalf("with a caller in the arguments the tool read %q, want the runtime's", got)
 	}
+	// A module's trusted list of callers (issue 774, ADR 0563 §8) grants the callers it names as the runtime proved them:
+	// a module on any machine, <machine>.<module> exactly, person.<name> exactly; no wildcard, never one unproven.
+	callers, err := ParseCallers([]byte(`{"callers":["node-tools","ace.claude-code","person.jo","*"]}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for caller, want := range map[string]bool{"shanks.node-tools": true, "ace.claude-code": true, "g14.claude-code": false,
+		"person.jo": true, "person.node-tools": false, Unproven: false, "": false, "novox.mesh-vault": false} {
+		if callers.Allows(caller) != want {
+			t.Errorf("%q allowed: %v, want %v", caller, !want, want)
+		}
+	}
+	if _, err := ParseCallers([]byte(`{"callers":["x"],"more":1}`)); err == nil {
+		t.Error("a list with a field it does not know was read")
+	}
 }
 
 // A runtime that names no caller — one from before issue 365, or a call on the subject that names none — is

go/callers.go

@@ -0,0 +1,48 @@
+package stdio
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+// Callers is a module's trusted list of who may call a verb of its (novox/hq ADR 0459 §2, ADR 0563 §8), as the mesh
+// writes a list setting into a file the module reads: `{"callers": [...]}`. An entry is a module's name (that module on
+// any machine), exactly <machine>.<module>, or exactly person.<name>. Each caller is the runtime's proof (CallerOf), never
+// an argument; nobody beyond the list is granted, a wildcard is no entry, and an unproven caller never matches.
+type Callers []string
+
+// ParseCallers reads a callers file: the list under `callers`, and nothing else.
+func ParseCallers(raw []byte) (Callers, error) {
+	var f struct {
+		Callers Callers `json:"callers"`
+	}
+	dec := json.NewDecoder(bytes.NewReader(raw))
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&f); err != nil {
+		return nil, fmt.Errorf("the callers setting is not a list of callers: %v", err)
+	}
+	return f.Callers, nil
+}
+
+// Allows says whether caller, as the runtime proved it, is one the list names.
+func (c Callers) Allows(caller string) bool {
+	if caller == "" || caller == Unproven {
+		return false
+	}
+	for _, entry := range c {
+		if entry == "" || strings.ContainsAny(entry, "*> ") {
+			continue
+		}
+		if entry == caller {
+			return true
+		}
+		if !strings.Contains(entry, ".") {
+			if _, module, ok := strings.Cut(caller, "."); ok && module == entry && !strings.HasPrefix(caller, "person.") {
+				return true
+			}
+		}
+	}
+	return false
+}