diff --git a/modules/mesh-delivery-sdk/buildstep/ask_test.go b/modules/mesh-delivery-sdk/buildstep/ask_test.go
index 258b5215..b94b15b1 100644
--- a/modules/mesh-delivery-sdk/buildstep/ask_test.go
+++ b/modules/mesh-delivery-sdk/buildstep/ask_test.go
@@ -11,7 +11,6 @@ import (
 	"testing"
 	"time"
 
-	"git.novox.be/novox/mesh-sdk/go/buscalls"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 )
 
@@ -350,9 +349,17 @@ func TestDeclinesNeedsAndLevelDigest(t *testing.T) {
 		hex := strings.Repeat("a", 64)
 		name, desc := KeptObject(KeptFor{Module: "demo", Fp: "fp1"}, "ace", "sha256:"+hex)
 		at := time.Date(2026, 11, 10, 10, 0, 0, 0, time.UTC)
-		kept := KeptBuildsOf([]buscalls.ObjectInfo{{Name: name, Size: 9, Description: desc, Modified: at},
-			{Name: "bb", Description: `{"module":"demo","fp":"fp1","node":"g14"}`}}, "ace")
-		if len(kept) != 1 || kept[0].Digest != hex || kept[0].Bytes != 9 {
+		var kept []KeptBuild
+		for _, o := range []struct {
+			name, desc string
+			size       uint64
+		}{{"cc", `{"module":"demo","fp":"fp0","node":"ace"}`, 1}, {name, desc, 9}, {"bb", `{"module":"demo","fp":"fp1","node":"g14"}`, 3}, {"dd", "not json", 4}} {
+			if k, ok := KeptBuildOf(o.name, o.desc, o.size, at, "ace"); ok {
+				kept = append(kept, k)
+			}
+		}
+		SortKept(kept)
+		if len(kept) != 2 || kept[0].Digest != hex || kept[0].Bytes != 9 || !kept[0].LastUsed.Equal(at) || kept[1].Digest != "cc" {
 			t.Fatalf("kept on ace: %+v", kept)
 		}
 		claims := func(m string) (bool, error) {
diff --git a/modules/mesh-delivery-sdk/buildstep/busfree_test.go b/modules/mesh-delivery-sdk/buildstep/busfree_test.go
index 3fae9d50..2b736983 100644
--- a/modules/mesh-delivery-sdk/buildstep/busfree_test.go
+++ b/modules/mesh-delivery-sdk/buildstep/busfree_test.go
@@ -3,6 +3,7 @@ package buildstep
 import (
 	"go/parser"
 	"go/token"
+	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -30,4 +31,15 @@ func TestThePackageIsFreeOfTheBus(t *testing.T) {
 			}
 		}
 	}
+	// Nor through a package it imports: a mesh-sdk package that came to import the bus library (buscalls' seat chunks) took
+	// the builder's published package onto the bus through this one (join 11).
+	out, err := exec.Command("go", "list", "-deps", ".").Output()
+	if err != nil {
+		t.Fatalf("go list: %v", err)
+	}
+	for _, p := range strings.Fields(string(out)) {
+		if strings.HasPrefix(p, "github.com/nats-io/") {
+			t.Errorf("buildstep depends on %s", p)
+		}
+	}
 }
diff --git a/modules/mesh-delivery-sdk/buildstep/keptartifact.go b/modules/mesh-delivery-sdk/buildstep/keptartifact.go
index 0282f781..56e91504 100644
--- a/modules/mesh-delivery-sdk/buildstep/keptartifact.go
+++ b/modules/mesh-delivery-sdk/buildstep/keptartifact.go
@@ -7,7 +7,6 @@ import (
 	"strings"
 	"time"
 
-	"git.novox.be/novox/mesh-sdk/go/buscalls"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 )
 
@@ -60,19 +59,20 @@ func KeptObject(k KeptFor, node, digest string) (name, description string) {
 	return strings.TrimPrefix(digest, "sha256:"), string(desc)
 }
 
-// KeptBuildsOf are the builds node keeps among a store's objects, by digest.
-func KeptBuildsOf(infos []buscalls.ObjectInfo, node string) []KeptBuild {
-	out := []KeptBuild{}
-	for _, i := range infos {
-		var k KeptBuild
-		if i.Deleted || json.Unmarshal([]byte(i.Description), &k) != nil || k.Node != node {
-			continue
-		}
-		k.Digest, k.Bytes, k.LastUsed = i.Name, i.Size, i.Modified.UTC()
-		out = append(out, k)
+// KeptBuildOf is the build node keeps under one object of a store, by its name (the digest), description, size and last change,
+// or false when the object names none of node's. The object's form is the build module's store's: this package reads no bus.
+func KeptBuildOf(name, description string, size uint64, modified time.Time, node string) (KeptBuild, bool) {
+	var k KeptBuild
+	if json.Unmarshal([]byte(description), &k) != nil || k.Node != node {
+		return KeptBuild{}, false
 	}
-	slices.SortFunc(out, func(a, b KeptBuild) int { return strings.Compare(a.Digest, b.Digest) })
-	return out
+	k.Digest, k.Bytes, k.LastUsed = name, size, modified.UTC()
+	return k, true
+}
+
+// SortKept orders kept builds by digest, the order kept-artifact's readers list them in.
+func SortKept(kept []KeptBuild) {
+	slices.SortFunc(kept, func(a, b KeptBuild) int { return strings.Compare(a.Digest, b.Digest) })
 }
 
 // ClaimsStoreOf reads the seat mesh-catalog's answer of one module (CatalogModuleVerb): whether its manifest claims the