From cde22ff6272445980d95794166646a365bec6376 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@novox.be>
Date: Sun, 4 Oct 2026 02:50:02 +0200
Subject: [PATCH] module check names a read of state its owner does not keep,
 and says what each module keeps and reads (novox/hq ADR 0201)

---
 cmd/mesh-controller/check.go         | 12 ++++++++++++
 internal/catalogue/seats_declared.go |  7 +++++++
 internal/catalogue/state_test.go     | 12 ++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/cmd/mesh-controller/check.go b/cmd/mesh-controller/check.go
index 1b01554..dbd9225 100644
--- a/cmd/mesh-controller/check.go
+++ b/cmd/mesh-controller/check.go
@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strings"
 
 	"github.com/novox/mesh-controller/internal/catalogue"
 )
@@ -90,6 +91,17 @@ func moduleCheck(paths []string, out io.Writer) error {
 		if len(m.Invokes) > 0 {
 			fmt.Fprintf(out, ", invokes %s", joinInvokes(m.Invokes))
 		}
+		// The state it keeps and reads (novox/hq ADR 0201), so a reviewer sees what lands on the bus.
+		if len(m.State) > 0 {
+			kept := make([]string, 0, len(m.State))
+			for _, s := range m.State {
+				kept = append(kept, s.Name)
+			}
+			fmt.Fprintf(out, ", keeps state %s", strings.Join(kept, ", "))
+		}
+		if len(m.Reads) > 0 {
+			fmt.Fprintf(out, ", reads %s", strings.Join(m.Reads, ", "))
+		}
 		fmt.Fprintln(out)
 	}
 	if failed > 0 {
diff --git a/internal/catalogue/seats_declared.go b/internal/catalogue/seats_declared.go
index f125cac..4afb221 100644
--- a/internal/catalogue/seats_declared.go
+++ b/internal/catalogue/seats_declared.go
@@ -215,6 +215,13 @@ func CatalogueProblems(shelf Shelf) []string {
 			}
 		}
 	}
+	// A read of a module's state that module does not keep (novox/hq ADR 0201) — said only where the
+	// owner is on the shelf, as a consumer may be installed before its emitter.
+	var manifests []Manifest
+	for _, module := range shelfOrder(shelf) {
+		manifests = append(manifests, shelf[module])
+	}
+	problems = append(problems, StateReadsNothingDeclares(manifests)...)
 	sort.Strings(problems)
 	return problems
 }
diff --git a/internal/catalogue/state_test.go b/internal/catalogue/state_test.go
index 4cf6206..6229787 100644
--- a/internal/catalogue/state_test.go
+++ b/internal/catalogue/state_test.go
@@ -80,3 +80,15 @@ func TestEveryManifestsStateIsLocalAndEveryReadIsKept(t *testing.T) {
 		t.Fatalf("the catalogue's state is not what ADR 0201 says:\n  %s", strings.Join(problems, "\n  "))
 	}
 }
+
+// `module check` says it too: the cross-catalogue pass names a read nothing on the shelf keeps.
+func TestTheCataloguePassNamesAReadItsOwnerDoesNotKeep(t *testing.T) {
+	shelf := Shelf{
+		"licence-manager": {Module: "licence-manager", State: []StateDeclaration{{Name: "bindings"}}},
+		"claude-code":     {Module: "claude-code", Reads: []string{"licence-manager.tokens"}},
+	}
+	problems := CatalogueProblems(shelf)
+	if len(problems) != 1 || !strings.Contains(problems[0], `keeps no state called "tokens"`) {
+		t.Fatalf("the catalogue pass said %v", problems)
+	}
+}