diff --git a/modules/docker/cmd/docker-tools/docker.go b/modules/docker/cmd/docker-tools/docker.go
index 872b8f3d..7411ac21 100644
--- a/modules/docker/cmd/docker-tools/docker.go
+++ b/modules/docker/cmd/docker-tools/docker.go
@@ -991,16 +991,27 @@ func (c *Client) Volumes(ctx context.Context, unmountedOnly, sizes bool) (map[st
 }
 
 // Events is what the runtime did in a window ending now, the latest last.
+//
+// **The runtime keeps only its last events in memory** (about 256), and the images' own health checks
+// make three exec events each per look: on a machine with a few checked containers that history is ten
+// minutes long or less, all of it exec events (hq research 032). A window asked for further back than
+// the history reaches is answered with what is still held AND says where the history begins, so an
+// empty list never reads as "nothing happened" (hq issue 348: three hours asked across an outage,
+// answered zero). The type filter is applied here rather than by the runtime, for the same reason: the
+// history's start is only known from all of it.
 func (c *Client) Events(ctx context.Context, minutes int, kind string, limit int, execs bool) (map[string]any, error) {
-	args := []string{"events", "--since", fmt.Sprintf("%dm", minutes), "--until", "0s", "--format", "{{json .}}"}
+	return c.eventsAt(ctx, time.Now(), minutes, kind, limit, execs)
+}
+
+func (c *Client) eventsAt(ctx context.Context, now time.Time, minutes int, kind string, limit int, execs bool) (map[string]any, error) {
 	if kind != "" {
 		switch kind {
 		case "container", "image", "network", "volume", "daemon", "plugin", "builder":
 		default:
 			return nil, fmt.Errorf("type %q: container, image, network, volume, daemon, plugin or builder", kind)
 		}
-		args = append(args, "--filter", "type="+kind)
 	}
+	args := []string{"events", "--since", fmt.Sprintf("%dm", minutes), "--until", "0s", "--format", "{{json .}}"}
 	out, err := c.docker(ctx, args...)
 	if err != nil {
 		return nil, err
@@ -1015,6 +1026,9 @@ func (c *Client) Events(ctx context.Context, minutes int, kind string, limit int
 	redacted := map[string]bool{}
 	events := []map[string]any{}
 	for _, e := range raw {
+		if kind != "" && e.Type != kind {
+			continue
+		}
 		if !execs && strings.HasPrefix(e.Action, "exec_") {
 			continue
 		}
@@ -1042,14 +1056,44 @@ func (c *Client) Events(ctx context.Context, minutes int, kind string, limit int
 	if len(events) > limit {
 		events = events[len(events)-limit:]
 	}
-	answer := map[string]any{"minutes": minutes, "count": total, "shown": len(events), "events": events}
+	answer := map[string]any{"minutes": minutes, "count": total, "shown": len(events), "events": events,
+		"held": len(raw)}
 	if len(redacted) > 0 {
 		answer["redacted"] = sortedSet(redacted)
 		answer["leak"] = "exec command lines carried secrets, which the runtime keeps in its events; docker_secrets_in_events names them (novox/hq issue 282)"
 	}
+	for k, v := range historyReach(raw, now, minutes) {
+		answer[k] = v
+	}
 	return answer, nil
 }
 
+// historyGap is how much later than the window's start the runtime's oldest held event may be and the
+// window still read as covered: events are not made every second.
+const historyGap = 2 * time.Minute
+
+// historyReach says where the runtime's history begins when it begins after the window asked for: the
+// oldest event it still holds, and that nothing before it can be answered from here.
+func historyReach(raw []runtimeEvent, now time.Time, minutes int) map[string]any {
+	start := now.Add(-time.Duration(minutes) * time.Minute)
+	if len(raw) == 0 {
+		return map[string]any{"complete": false,
+			"history": "the runtime holds no events at all for this window: it keeps only its last events in memory, so this says nothing about what happened before now — ask the service manager's journal for the docker unit"}
+	}
+	oldest := time.Unix(0, raw[0].TimeNano)
+	for _, e := range raw {
+		if t := time.Unix(0, e.TimeNano); t.Before(oldest) {
+			oldest = t
+		}
+	}
+	if oldest.Sub(start) <= historyGap {
+		return map[string]any{"complete": true, "oldest_held": oldest.UTC().Format(time.RFC3339)}
+	}
+	return map[string]any{"complete": false, "oldest_held": oldest.UTC().Format(time.RFC3339),
+		"history": fmt.Sprintf("the runtime keeps only its last %d events in memory and its oldest is from %s; the window asked starts at %s, so what happened before %s is gone from here, not absent — the images' health checks fill the history with exec events (hq research 032)",
+			len(raw), oldest.UTC().Format(time.RFC3339), start.UTC().Format(time.RFC3339), oldest.UTC().Format("15:04:05Z"))}
+}
+
 func sortedSet(set map[string]bool) []string {
 	out := make([]string, 0, len(set))
 	for k := range set {
diff --git a/modules/docker/cmd/docker-tools/docker_test.go b/modules/docker/cmd/docker-tools/docker_test.go
index 22774e83..41ff8eb7 100644
--- a/modules/docker/cmd/docker-tools/docker_test.go
+++ b/modules/docker/cmd/docker-tools/docker_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io/fs"
 	"os"
 	"reflect"
@@ -307,7 +308,8 @@ func TestEventsAreABoundedWindowWithoutExecNoise(t *testing.T) {
 	if len(evs) != 1 || evs[0]["action"] != "die" || evs[0]["mesh_held"] != true || evs[0]["exit_code"] != "137" {
 		t.Fatalf("%v", evs)
 	}
-	if !f.ran("docker events --since 30m --until 0s --format {{json .}} --filter type=container") {
+	// The type is filtered here, not by the runtime: the history's start is only known from all of it (issue 348).
+	if !f.ran("docker events --since 30m --until 0s --format {{json .}}") || f.ran("docker events --since 30m --until 0s --format {{json .}} --filter") {
 		t.Fatalf("%+v", f.calls)
 	}
 	if _, err := client(f, 1000).Events(context.Background(), 30, "secret", 10, false); err == nil {
@@ -362,3 +364,52 @@ func TestProblemsNameWhyAndUnlabelledIsTheCleanupList(t *testing.T) {
 		t.Fatalf("%v %v", u, err)
 	}
 }
+
+// eventLine is one line of `docker events --format '{{json .}}'`.
+func eventLine(at time.Time, kind, action, name string) string {
+	return fmt.Sprintf(`{"Type":%q,"Action":%q,"Actor":{"ID":"abcdef0123456789","Attributes":{"name":%q}},"timeNano":%d}`+"\n",
+		kind, action, name, at.UnixNano())
+}
+
+// Issue 348: three hours asked across an outage answered zero, because the runtime's history held only the
+// last ten minutes of health-check execs. The answer must say the history is short, not that nothing happened.
+func TestEventsSayWhereTheRuntimesHistoryBeginsWhenTheWindowReachesFurther(t *testing.T) {
+	now := time.Date(2026, 10, 9, 11, 24, 0, 0, time.UTC)
+	var out strings.Builder
+	for i := 0; i < 250; i++ {
+		out.WriteString(eventLine(now.Add(-10*time.Minute+time.Duration(i)*2*time.Second), "container", "exec_die", "mailu-webmail"))
+	}
+	got, err := client((&fake{}).on("docker events", Ran{Stdout: out.String()}), 1000).eventsAt(context.Background(), now, 180, "", 200, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got["count"] != 0 || got["held"] != 250 {
+		t.Fatalf("count %v held %v, want 0 shown of 250 held", got["count"], got["held"])
+	}
+	if got["complete"] != false || !strings.Contains(fmt.Sprint(got["history"]), "gone from here, not absent") ||
+		got["oldest_held"] != "2026-10-09T11:14:00Z" {
+		t.Fatalf("an empty answer from a short history reads as quiet: %v", got)
+	}
+}
+
+func TestEventsCoveringTheWholeWindowSayItIsCompleteAndFilterTheTypeHere(t *testing.T) {
+	now := time.Date(2026, 10, 9, 11, 24, 0, 0, time.UTC)
+	out := eventLine(now.Add(-59*time.Minute), "network", "destroy", "build-net") +
+		eventLine(now.Add(-30*time.Minute), "container", "die", "build-bus") +
+		eventLine(now.Add(-1*time.Minute), "network", "create", "build-net")
+	f := (&fake{}).on("docker events", Ran{Stdout: out})
+	got, err := client(f, 1000).eventsAt(context.Background(), now, 60, "network", 200, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got["complete"] != true || got["count"] != 2 || got["history"] != nil {
+		t.Fatalf("a covered window: %v", got)
+	}
+	if f.ran("docker events --since 60m --until 0s --format {{json .}} --filter") {
+		t.Fatal("the type was filtered by the runtime, so the history's start is unknown")
+	}
+	got, _ = client((&fake{}).on("docker events", Ran{}), 1000).eventsAt(context.Background(), now, 60, "", 200, false)
+	if got["complete"] != false || got["history"] == nil {
+		t.Fatalf("no events at all reads as quiet: %v", got)
+	}
+}
diff --git a/modules/docker/cmd/docker-tools/main.go b/modules/docker/cmd/docker-tools/main.go
index f5c812ea..9e95a39d 100644
--- a/modules/docker/cmd/docker-tools/main.go
+++ b/modules/docker/cmd/docker-tools/main.go
@@ -262,7 +262,8 @@ func tools(c *Client) []stdio.Tool {
 		{
 			Name: "docker_events",
 			Description: "What the runtime did in a window ending now (default the last 60 minutes, at most 24 hours): containers created, started, died, health changes, images pulled — with mesh_held. Exec events are left out unless asked; " +
-				"an exec's command line is shown with any secret it carried as [redacted: <what it was>] — a value of the container's environment named like a secret, a password in a URI, the word after a password flag.",
+				"an exec's command line is shown with any secret it carried as [redacted: <what it was>] — a value of the container's environment named like a secret, a password in a URI, the word after a password flag. " +
+				"The runtime keeps only its last ~256 events in memory, which health-check execs fill in minutes: complete=false and history say where what it holds begins, and an empty list then means gone, not quiet.",
 			Input: map[string]any{
 				"minutes": map[string]any{"type": "integer", "description": "how far back (default 60, at most 1440)"},
 				"type":    map[string]any{"type": "string", "description": "only one kind: container, image, network, volume, daemon, plugin or builder"},