The builder's build log has a cap that holds its 30 days (issue 1966, recovery)

The log grew about 3 MiB an hour on 2026-11-09 (951.9 MiB at 07:47 UTC, 954.9 at 08:42)
against the bus's default cap of 1 GiB, about 23 hours before builds stop. ADR 0571 §1
keeps it 30 days, so the cap rises to 3072 MiB instead of the age falling.

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i

modules/mesh-delivery-builder/builds/log.go

@@ -27,6 +27,9 @@ const (
 	BuildSaidEvent = "build.said"
 	// BuilderLogDays is how long the log keeps its entries.
 	BuilderLogDays = 30
+	// BuilderLogMiB is the log's cap: 30 days of entries, at the 3 MiB an hour read on 2026-11-09, with room to spare.
+	// The bus's default of 1 GiB held about two weeks of them (issue 1966).
+	BuilderLogMiB = 3072
 	// BuildsSinceTool is the builder's tool answering every ended build since a time, in order (clause 9): its
 	// argument `since` (RFC 3339), its answer BuildsSince.
 	BuildsSinceTool = "builder_builds_since"

modules/mesh-delivery-builder/manifest_test.go

@@ -48,6 +48,7 @@ type manifest struct {
 	Logs     []struct {
 		Name       string `json:"name"`
 		MaxAgeDays int    `json:"max-age-days"`
+		MaxMiB     int    `json:"max-mib"`
 	} `json:"logs"`
 	Reads   []string `json:"reads"`
 	Uses    []string `json:"uses"`
@@ -159,9 +160,9 @@ func TestManifestDeclarations(t *testing.T) { // 1607/AC1
 	if want := []string{"build.asked-again", "version.numbered", "version.old-form-closed"}; !reflect.DeepEqual(m.Emits, want) {
 		t.Errorf("emits = %v, want %v", m.Emits, want)
 	}
-	// 1955/L7 (ADR 0571 §1): its module log, each build's start and end, kept 30 days; no bare stream.
-	if len(m.Logs) != 1 || m.Logs[0].Name != builds.BuilderLog || m.Logs[0].MaxAgeDays != builds.BuilderLogDays {
-		t.Errorf("logs = %+v, want %s kept %d days", m.Logs, builds.BuilderLog, builds.BuilderLogDays)
+	// 1955/L7 (ADR 0571 §1): its module log, each build's start and end, kept 30 days in a cap that holds them; no bare stream.
+	if len(m.Logs) != 1 || m.Logs[0].Name != builds.BuilderLog || m.Logs[0].MaxAgeDays != builds.BuilderLogDays || m.Logs[0].MaxMiB != builds.BuilderLogMiB {
+		t.Errorf("logs = %+v, want %s kept %d days in %d MiB", m.Logs, builds.BuilderLog, builds.BuilderLogDays, builds.BuilderLogMiB)
 	}
 	for _, k := range []string{"streams", "claims", "provides", "requires", "defines-seats", "seat", "seats", "bus", "config"} {
 		if _, ok := top[k]; ok {

modules/mesh-delivery-builder/module.json

@@ -95,7 +95,7 @@
     { "name": "first-views", "history": 1 }
   ],
   "logs": [
-    { "name": "build-log", "max-age-days": 30 }
+    { "name": "build-log", "max-age-days": 30, "max-mib": 3072 }
   ],
   "reads": [
     "mesh-build-go.steps",