A check that what the control plane emits is what this host accepts

"The host needs no new vocabulary" is the load-bearing claim behind every
computed and contributed resource on the other side, and it had never
been tested against this parser — only asserted.

Skipped unless MESH_EMITTED names a file, so it stays a check somebody
runs deliberately rather than a dependency between two repositories.

  mesh-control plan <node> --json > /tmp/d.json
  MESH_EMITTED=/tmp/d.json go test ./internal/declaration/ -v

Confirmed to fail when the declaration carries an action, which is the
thing this parser exists to refuse.

internal/declaration/emitted_check_test.go

@@ -0,0 +1,33 @@
+package declaration
+
+import (
+	"os"
+	"testing"
+)
+
+// The control plane's actual output, put through the host's actual parser.
+//
+// Skipped unless MESH_EMITTED names a file, so this is a check somebody runs deliberately rather
+// than a dependency between two repositories. It exists because "the host needs no new
+// vocabulary" is the load-bearing claim of every computed and contributed resource, and the only
+// honest way to know it is to hand the host one and see.
+func TestWhatTheControlPlaneEmittedIsSomethingThisHostAccepts(t *testing.T) {
+	path := os.Getenv("MESH_EMITTED")
+	if path == "" {
+		t.Skip("set MESH_EMITTED to a declaration the control plane produced")
+	}
+	raw, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	d, err := Parse(raw)
+	if err != nil {
+		t.Fatalf("the host refuses what the control plane sends:\n%v", err)
+	}
+	if len(d.Resources) == 0 {
+		t.Fatal("parsed, and empty")
+	}
+	for _, r := range d.Resources {
+		t.Logf("accepted %s %s → %s", r.Kind(), r.Identity(), r.Target())
+	}
+}