diff --git a/cmd/mavend/actions_act.go b/cmd/mavend/actions_act.go
index ea024a8..024f1b6 100644
--- a/cmd/mavend/actions_act.go
+++ b/cmd/mavend/actions_act.go
@@ -60,6 +60,17 @@ func (h *reactiveHandler) actionAct(ctx context.Context, dec router.Decision) st
 			phrase := actPhrase(dec.Slots.Fn, dec.Slots.Args)
 			h.park(dec.Slots.Fn, dec.Slots.Args, phrase)
 			return phraser.A(phraser.ActConfirm, map[string]string{"name": phrase})
+		case errors.Is(err, tool.ErrUnknownTarget):
+			// The verb reached a tool and the tail did not reach a target, so
+			// nothing ran. Saying which word she could not place is the whole
+			// answer: he either renames it or gives the row an alias that
+			// carries the target, and both are one turn away (V-634).
+			word := ""
+			var unknown *tool.UnknownTargetError
+			if errors.As(err, &unknown) {
+				word = unknown.Target
+			}
+			return phraser.A(phraser.ActUnknownTarget, map[string]string{"name": word})
 		case errors.Is(err, tool.ErrNeedsAuthedSurface):
 			// Irreversible (internal/tool/risk.go). A confirm turn would not
 			// help: everything that proposed this act — the STT, the router,
@@ -93,3 +104,4 @@ func (h *reactiveHandler) actionAct(ctx context.Context, dec router.Decision) st
 	}
 	return phraser.A(phraser.ActDone, nil)
 }
+
diff --git a/internal/phraser/acts.go b/internal/phraser/acts.go
index d3b85d7..975cf3a 100644
--- a/internal/phraser/acts.go
+++ b/internal/phraser/acts.go
@@ -45,6 +45,10 @@ const (
 	// is the only authority the voice path can offer, and this is the one act
 	// it is not enough for (Vikunja #449, #523).
 	ActNeedsAuthedSurface = "act_needs_authed_surface"
+	// ActUnknownTarget — the verb reached a tool and the target did not reach
+	// anything. Named rather than run, because the alias match swallowed the verb
+	// and handed on the next word of the sentence (V-634).
+	ActUnknownTarget = "act_unknown_target"
 
 	EcoDenied        = "eco_denied"
 	EcoDown          = "eco_down"
@@ -76,7 +80,7 @@ const (
 var actKeys = []string{
 	ActDone, ActDoneOut, ActDoneEntity, ActConfirm, ActConfirmEntity, ActWhich,
 	ActFail, ActFailOut, ActFailEntity, ActServerDown, ActWithdrawn, ActNeedsArgs,
-	ActNeedsAuthedSurface,
+	ActNeedsAuthedSurface, ActUnknownTarget,
 	EcoDenied, EcoDown, EcoAmbiguous, EcoUnknownEntity, EcoNoNexus, EcoAboutWhat, EcoRecall,
 	AttentionNone, AttentionList, AttentionFail,
 	AttentionNoneEntity, AttentionListEntity, AttentionFailEntity,
@@ -102,6 +106,7 @@ var actFloor = map[string]string{
 	ActServerDown:         "инструмент есть, но сервер не подключён.",
 	ActWithdrawn:          "сервер больше не отдаёт этот инструмент — сняла его с разрешённых, посмотри /tools.",
 	ActNeedsArgs:          "тут нужны аргументы, из голоса не соберу. угадывать не буду.",
+	ActUnknownTarget:      "«{name}» — не знаю такой цели. назови её как в системе.",
 	ActNeedsAuthedSurface: "это из голоса не выполню — после него ничего не вернуть. запусти сам.",
 
 	EcoDenied:        "{name} отклоняет доступ, проверь токен.",
diff --git a/internal/phraser/acts_ru_v1.json b/internal/phraser/acts_ru_v1.json
index 4d66e9e..9b05fc8 100644
--- a/internal/phraser/acts_ru_v1.json
+++ b/internal/phraser/acts_ru_v1.json
@@ -60,6 +60,10 @@
       "fixed": true,
       "variants": ["тут нужны аргументы, из голоса не соберу. угадывать не буду."]
     },
+    "act_unknown_target": {
+      "fixed": true,
+      "variants": ["«{name}» — не знаю такой цели. назови её как в системе."]
+    },
     "act_needs_authed_surface": {
       "fixed": true,
       "variants": ["это из голоса не выполню — после него ничего не вернуть. запусти сам."]
diff --git a/internal/tool/tool.go b/internal/tool/tool.go
index 60842d2..cb7bf9e 100644
--- a/internal/tool/tool.go
+++ b/internal/tool/tool.go
@@ -39,6 +39,7 @@ import (
 	"os/exec"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/kami/maven/internal/ipc"
 	"github.com/kami/maven/internal/mcp"
@@ -73,8 +74,27 @@ var (
 	// confirm turn that would help: asking again would imply the second answer
 	// changes the outcome.
 	ErrNeedsAuthedSurface = errors.New("tool is irreversible and voice may not authorise it")
+	// ErrUnknownTarget — the act matched a tool and the target it carries cannot
+	// be one. A process row's args become argv for a real program, and a unit,
+	// container or host is named in ASCII on this box, so a Cyrillic tail is a
+	// word from the sentence rather than a target. Held apart from every failure
+	// above because the command never ran: forwarding it would spend a confirm
+	// turn on an act that cannot succeed, and then report the program's own
+	// confusion as if she had tried something sensible (V-634).
+	ErrUnknownTarget = errors.New("the act names a target the system cannot have")
 )
 
+// UnknownTargetError carries the word the executor could not place, because the
+// reply names it: "«роутер» — не знаю такой цели" is actionable and "не
+// получилось" sends him to the log. errors.Is(err, ErrUnknownTarget) holds.
+type UnknownTargetError struct{ Target string }
+
+func (e *UnknownTargetError) Error() string {
+	return fmt.Sprintf("%s: %q", ErrUnknownTarget, e.Target)
+}
+
+func (e *UnknownTargetError) Unwrap() error { return ErrUnknownTarget }
+
 // MCPCaller is the seam for an act that is an MCP tool call rather than a
 // process (Vikunja #251). internal/mcp.Manager satisfies it via CallPositional.
 // nil ⇒ MCP is not configured, and an MCP row refuses to run rather than
@@ -144,6 +164,16 @@ func (e *Executor) Exec(ctx context.Context, name string, args []string, confirm
 	if t.Status != "enabled" {
 		return "", ErrNotEnabled
 	}
+	// A process row's args become argv, so the target has to be able to exist.
+	// Checked before the confirm gate below, because asking "выполнить X?" about
+	// an act that cannot run spends a turn on nothing (V-634). The other two
+	// dispatches are exempt: an MCP tool may take Russian text as an argument,
+	// since a task title is not a target, and a house row drops the spoken args.
+	if !isMCPRow(t.Cmd) && !isHouseRow(t.Cmd) {
+		if bad, ok := firstUnknownTarget(args); !ok {
+			return "", &UnknownTargetError{Target: bad}
+		}
+	}
 	// The tier decides, not the column (Vikunja #449). RiskOf reads the row and
 	// answers the three questions the boolean never did: which acts are
 	// destructive, whether a confirm sticks (it never does), and what an
@@ -260,3 +290,41 @@ func (m *Matcher) Allowlist() []string { return m.names() }
 func (m *Matcher) Match(utterance string) (string, []string, bool) {
 	return router.DefaultActMatcher{Fns: m.names(), Aliases: m.aliases}.Match(utterance)
 }
+
+// firstUnknownTarget reports whether every arg could name something on this box,
+// and returns the first that could not.
+//
+// The check is the script, not a word list: this is not a fourth Russian
+// mechanism (CLAUDE.md § "Russian patterns"). A systemd unit, a container, a
+// host and a path are written in ASCII, so a non-ASCII rune in an argv element
+// means the alias match swallowed the verb and handed on the next word of the
+// sentence. "перезагрузи роутер" is the case: restart is a real tool and
+// "роутер" is a real word, and `systemctl restart роутер` is neither.
+//
+// Every process row this box enables takes a system identifier (systemctl,
+// docker, journalctl, df). A process row that legitimately wanted Russian text
+// would want a different dispatch, not a hole in this check.
+//
+// It deliberately does not try to guess the right target. Identity is Nexus's
+// (CLAUDE.md § "The ecosystem"), and a target Nexus resolves reaches Hexis
+// through handleHexisAct before this executor is asked.
+func firstUnknownTarget(args []string) (string, bool) {
+	for _, a := range args {
+		for _, r := range a {
+			if r > unicode.MaxASCII {
+				return a, false
+			}
+		}
+	}
+	return "", true
+}
+
+func isMCPRow(cmd []string) bool {
+	_, _, ok := mcp.ParseCmd(cmd)
+	return ok
+}
+
+func isHouseRow(cmd []string) bool {
+	_, _, ok := smarthome.ParseCmd(cmd)
+	return ok
+}
diff --git a/internal/tool/tool_test.go b/internal/tool/tool_test.go
index 4eea1da..ac98d4c 100644
--- a/internal/tool/tool_test.go
+++ b/internal/tool/tool_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 
@@ -320,3 +321,55 @@ func TestExecEmptyCmdRefuses(t *testing.T) {
 		t.Fatal("a row with no cmd ran a program named by the utterance")
 	}
 }
+
+// V-634. The alias match resolves the verb and hands on the next word of the
+// sentence, so "перезагрузи роутер" became `systemctl restart роутер`: a real
+// tool, a real word, and a target that cannot exist on this box.
+func TestExecRefusesATargetTheSystemCannotHave(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"restart": {Name: "restart", Cmd: []string{"systemctl", "restart"}, Status: "enabled"},
+		"drop": {Name: "drop", Cmd: []string{"dropdb"}, Destructive: true, Status: "enabled"},
+	}}
+	ran := false
+	e := NewExecutor(api, 0)
+	e.run = func(context.Context, []string) (string, error) { ran = true; return "ok", nil }
+
+	_, err := e.Exec(context.Background(), "restart", []string{"роутер"}, false)
+	if !errors.Is(err, ErrUnknownTarget) {
+		t.Fatalf("err = %v, want ErrUnknownTarget", err)
+	}
+	if ran {
+		t.Fatal("the program was called with a target that cannot exist")
+	}
+	// The word is in the error, because a reply naming no word sends him to the log.
+	if !strings.Contains(err.Error(), "роутер") {
+		t.Errorf("err %v does not name the word she could not place", err)
+	}
+	// Ahead of the confirm gate: asking about an act that cannot run spends a
+	// turn on nothing.
+	if _, err := e.Exec(context.Background(), "drop", []string{"база"}, false); !errors.Is(err, ErrUnknownTarget) {
+		t.Errorf("destructive row: err = %v, want ErrUnknownTarget before ErrNeedsConfirm", err)
+	}
+	// An ASCII target still runs, unchanged.
+	if _, err := e.Exec(context.Background(), "restart", []string{"nginx"}, false); err != nil {
+		t.Errorf("restart nginx: %v", err)
+	}
+}
+
+// An MCP argument is not a target. A task title is Russian and always was.
+func TestExecMCPRowKeepsRussianArgs(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"vikunja_create": {
+			Name: "vikunja_create", Status: "enabled",
+			Cmd: []string{"mcp", "vikunja", "create_task"},
+		},
+	}}
+	m := &fakeMCP{out: "создала"}
+	e := NewExecutor(api, time.Second).WithMCP(m)
+	if _, err := e.Exec(context.Background(), "vikunja_create", []string{"купить хлеб"}, false); err != nil {
+		t.Fatalf("exec: %v", err)
+	}
+	if len(m.args) != 1 || m.args[0] != "купить хлеб" {
+		t.Fatalf("args = %v, want the Russian title forwarded", m.args)
+	}
+}