Keep a machine's discovery answer under the bus's message limit

Every tool's schema in one $SRV.INFO reply outgrew max_payload on machines
serving 137-206 tools, and the refused reply was dropped silently, so search
and a machine's view went empty. Module tools now announce without schema;
describe and tools/list ask the module for it. An answer still too large has
its descriptions cut to a line, and a failed reply is logged.

node-tools/internal/console/address.go

@@ -691,6 +691,10 @@ func (s *Surface) discover(name string, args map[string]any) map[string]any {
 		if err != nil {
 			return failure(err.Error())
 		}
+		if !t.Seat && len(t.Tool.Input) == 0 {
+			// Discovery carries a seat's schema, not a module tool's: asked of the runtime serving it.
+			t.Tool.Input = inputOf(s.conn, t.Tool.Module, t.Tool.Name)
+		}
 		description := t.Tool.Description
 		if description == "" {
 			description = t.Name
@@ -728,3 +732,29 @@ func (s *Surface) discover(name string, args map[string]any) map[string]any {
 	}
 	return failure("no discovery verb " + name)
 }
+
+// inputOf is a module tool's input schema, asked of a runtime that serves the module — its `tools` verb,
+// answered on the module's plain subject by any instance — because discovery no longer carries it: every
+// tool's schema made a machine's one discovery answer outgrow the bus (2026-10-04). Nil when nothing
+// answers, which describes the tool as taking nothing rather than failing the description.
+func inputOf(conn *bus.Conn, module, tool string) json.RawMessage {
+	got, err := conn.Ask(module+".tools", map[string]any{}, "")
+	if err != nil {
+		return nil
+	}
+	var answer struct {
+		Tools []struct {
+			Name  string          `json:"name"`
+			Input json.RawMessage `json:"input"`
+		} `json:"tools"`
+	}
+	if json.Unmarshal(got.Result, &answer) != nil {
+		return nil
+	}
+	for _, t := range answer.Tools {
+		if t.Name == tool {
+			return t.Input
+		}
+	}
+	return nil
+}