diff --git a/go/buscalls/buscalls.go b/go/buscalls/buscalls.go
index 44e007d4..e24f5613 100644
--- a/go/buscalls/buscalls.go
+++ b/go/buscalls/buscalls.go
@@ -31,6 +31,8 @@ const (
 
 	StreamRead = "mesh/stream.read"
 	StreamFill = "mesh/stream.fill"
+	// StreamPublish says one event on the module's own bound stream (A-42).
+	StreamPublish = "mesh/stream.publish"
 
 	WorkQueueSize = "mesh/workqueue.size"
 	WorkQueueDead = "mesh/workqueue.dead"
@@ -153,6 +155,20 @@ type StreamPage struct {
 	Last     uint64          `json:"last"`
 }
 
+// StreamPublishRequest says one event on a module's own stream, by the stream's local name: the tool runner publishes
+// Body on the binding's subject plus "." plus Event, acknowledged, with ID as the message id (design 42 zfs-owns-zfs, A-42).
+type StreamPublishRequest struct {
+	Stream string          `json:"stream"`
+	Event  string          `json:"event"`
+	Body   json.RawMessage `json:"body"`
+	ID     string          `json:"id,omitempty"`
+}
+
+// StreamPublished is publish's answer: the sequence the stream acknowledged the event at.
+type StreamPublished struct {
+	Sequence uint64 `json:"sequence"`
+}
+
 // StreamFilled is fill's answer: the stream's fill and its first and last sequence.
 type StreamFilled struct {
 	Fill
diff --git a/go/buscalls/buscalls_test.go b/go/buscalls/buscalls_test.go
new file mode 100644
index 00000000..01cf18d4
--- /dev/null
+++ b/go/buscalls/buscalls_test.go
@@ -0,0 +1,21 @@
+package buscalls
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// A-42: stream.publish is a method of its own, beside read and fill, and its request and answer keep their field names.
+func TestStreamPublishIsAMethodWithItsShapes(t *testing.T) {
+	if StreamPublish != "mesh/stream.publish" || StreamPublish == StreamRead || StreamPublish == StreamFill {
+		t.Fatalf("method %q", StreamPublish)
+	}
+	b, _ := json.Marshal(StreamPublishRequest{Stream: "events", Event: "scrub.requested", Body: json.RawMessage(`{"a":1}`), ID: "x"})
+	if string(b) != `{"stream":"events","event":"scrub.requested","body":{"a":1},"id":"x"}` {
+		t.Errorf("request %s", b)
+	}
+	a, _ := json.Marshal(StreamPublished{Sequence: 7})
+	if string(a) != `{"sequence":7}` {
+		t.Errorf("answer %s", a)
+	}
+}