tool, mavend: cover the tiers end to end (V-449)

The Destructive column was a mechanism with no policy behind it: nothing said
which acts are destructive, whether a confirmed act stays confirmed, or what a
new tool domain inherits, so each domain answered for itself.

Three tiers, derived from the row rather than stored, so the answer can be
argued with in one place instead of being whatever the last person to tick the
checkbox believed. Safe runs. Destructive costs a confirm turn, every time —
a confirmation binds one capability, one target and one argument list, and it
dies with the parked turn. Irreversible is refused: a confirm turn there would
be theatre, because the STT, the router and the fuzzy allowlist match are all
guesses and a spoken "да" checks none of them. She names the gap; the row
stays enabled.

An unrecognised dispatch shape inherits destructive, not safe. A domain argues
its way down to running freely, never up to being gated.

cmd/mavend/actions_act.go

@@ -51,6 +51,12 @@ 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 "выполнить «" + phrase + "»? скажи «да» или «нет»."
+		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,
+			// the fuzzy allowlist match — is a guess, and a spoken "да" checks
+			// none of it. She names the gap instead.
+			return "это я из голоса не выполню — после него ничего не вернуть. запусти сам, если правда надо."
 		case errors.Is(err, tool.ErrNotEnabled):
 			return h.proposeGap(ctx, dec)
 		case errors.Is(err, tool.ErrNotConnected), errors.Is(err, mcp.ErrNotConnected), errors.Is(err, mcp.ErrNoServer):

cmd/mavend/actions_act_risk_test.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/kami/maven/internal/router"
+)
+
+// The act path speaks each tier (Vikunja #449): a safe row runs, a destructive
+// one costs a confirm turn, an irreversible one is refused with the reason.
+func TestActPathSpeaksTheTiers(t *testing.T) {
+	h, st, _ := newClarifyHandler(t)
+	ctx := context.Background()
+	now := h.now()
+	for _, tc := range []struct {
+		name        string
+		cmd         []string
+		destructive bool
+	}{
+		{"status", []string{"true"}, false},
+		{"restart", []string{"true"}, true},
+		{"wipe", []string{"rm", "-rf"}, true},
+	} {
+		if _, err := st.ProposeTool(ctx, tc.name, "test", "homelab", now); err != nil {
+			t.Fatalf("propose %s: %v", tc.name, err)
+		}
+		if err := st.EnableTool(ctx, tc.name, tc.cmd, tc.destructive, "homelab", now); err != nil {
+			t.Fatalf("enable %s: %v", tc.name, err)
+		}
+	}
+
+	act := func(fn string) string {
+		return h.actionAct(ctx, router.Decision{
+			Intent:    router.IntentAct,
+			Utterance: fn,
+			Slots:     router.Slots{Fn: fn, HasFn: true},
+		})
+	}
+
+	if reply := act("status"); !strings.HasPrefix(reply, "готово") {
+		t.Errorf("safe act replied %q; want it to have run", reply)
+	}
+	if reply := act("restart"); !strings.Contains(reply, "скажи «да»") {
+		t.Errorf("destructive act replied %q; want a confirm turn", reply)
+	}
+	// Clear the confirm the destructive act parked, so what is pending after
+	// the irreversible one is only what the irreversible one parked.
+	h.mu.Lock()
+	h.pending = nil
+	h.mu.Unlock()
+
+	reply := act("wipe")
+	if strings.Contains(reply, "скажи «да»") {
+		t.Fatalf("irreversible act asked for a confirm: %q", reply)
+	}
+	if !strings.Contains(reply, "не вернуть") {
+		t.Errorf("irreversible act replied %q; want it to name the reason", reply)
+	}
+	// Nothing was parked, so a later "да" cannot pick it up.
+	h.mu.Lock()
+	pending := h.pending
+	h.mu.Unlock()
+	if pending != nil {
+		t.Errorf("an irreversible act parked %+v", pending)
+	}
+	// And it is still an enabled row — refusing to run it from voice is not
+	// the same as taking it off the allowlist.
+	if got, err := st.LookupTool(ctx, "wipe"); err != nil || got.Status != "enabled" {
+		t.Errorf("wipe is %+v, %v; want it still enabled", got, err)
+	}
+}

docs/design.md

@@ -293,6 +293,40 @@ don't improvise.** Destructive ones still gate behind confirm.
 Misroute correction is append-only and grows the router's examples with use —
 same shape as `nudges.outcome` tuning cooldowns, no retrain.
 
+#### Risk tiers, not one boolean
+
+`Destructive` on a tool row is one bit set by whoever ticked the checkbox on
+`/tools`. It is a mechanism, and it never said which acts are destructive,
+whether a confirmed act stays confirmed, or what a new tool domain inherits.
+`internal/tool/risk.go` is the policy (Vikunja #449). The tier is DERIVED from
+the row, not stored, so it can be argued with in one place instead of being
+whatever the last person to enable the tool believed.
+
+| Tier | What it is | What it costs |
+|---|---|---|
+| `safe` | a read, or a change he can undo by saying the opposite | runs on first hearing |
+| `destructive` | it changes something real and undoing it takes work | one confirm turn, every time |
+| `irreversible` | the thing does not come back: a wipe, a format, a delete with no bin | voice may not authorise it at all |
+
+Three rules fall out, and they are the part that was missing:
+
+- **Which acts are destructive is not only the checkbox.** A house row always
+  is, because there is no read-only way to turn the heating off. A row whose
+  argv names one of the irreversible verbs always is, whatever the row says.
+- **A confirmed act never stays confirmed.** At any tier. A confirmation binds
+  one capability, one target and one argument list, and it dies with the parked
+  turn (90s). "The same act again" is a new act. A sticky confirm is a standing
+  grant and nothing on the voice path may hold one.
+- **A new domain inherits `destructive`, not `safe`.** A dispatch shape the
+  policy does not recognise gets the confirm turn. A domain argues its way down
+  to running freely; it never has to argue its way up to being gated.
+
+The irreversible tier is refused rather than asked about, because a confirm
+turn would be theatre: everything that proposed the act — an STT guess, a
+router guess, a fuzzy allowlist match — is a guess, and a spoken "да" checks
+none of it. She names the gap and he runs it himself. The row stays enabled;
+refusing to run it from voice is not the same as taking it off the allowlist.
+
 ---
 
 ## Voice pipeline (STT / TTS)

internal/tool/risk.go

@@ -0,0 +1,145 @@
+package tool
+
+import (
+	"strings"
+
+	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/mcp"
+	"github.com/kami/maven/internal/smarthome"
+)
+
+// Risk tiers (Vikunja #449).
+//
+// What existed before this file was a mechanism and no policy: one
+// `Destructive` boolean per row, set by whoever ticked the checkbox on /tools.
+// Nothing said which acts are destructive, whether a confirmed act stays
+// confirmed, or what a new tool domain inherits — so every domain answered
+// those questions for itself, and two of them answered differently.
+//
+// The tiers below are the policy. They are derived from the row, not stored:
+// a derivation can be argued with and corrected in one place, while a column
+// is whatever the last person to enable the tool believed.
+//
+// The three questions, answered once:
+//
+//   - WHICH ACTS ARE DESTRUCTIVE. A house row always is, because there is no
+//     read-only way to turn the heating off. A row whose argv names one of the
+//     irreversible verbs always is, whatever the checkbox says. Everything else
+//     is what the row was enabled as.
+//   - DOES A CONFIRMED ACT STAY CONFIRMED. No. Never, at any tier. A
+//     confirmation binds one capability, one target and one argument list, and
+//     it expires with the parked turn (confirmTTL, 90s). "Same act again" is a
+//     new act and costs a new turn. A sticky confirm is a standing grant, and
+//     nothing on the voice path may hold one.
+//   - WHAT A NEW DOMAIN INHERITS. The default is TierDestructive, not
+//     TierSafe. A dispatch shape this file does not recognise gets the confirm
+//     turn — a new domain must argue its way DOWN to running freely, never up
+//     to needing a confirm.
+type Risk string
+
+const (
+	// TierSafe — a read, or a mutation the owner can undo by saying the
+	// opposite. Runs on first hearing.
+	TierSafe Risk = "safe"
+	// TierDestructive — it changes something real and undoing it takes work.
+	// One confirm turn, every time, never remembered.
+	TierDestructive Risk = "destructive"
+	// TierIrreversible — the thing it acts on does not come back: a wipe, a
+	// format, a delete with no bin behind it. A confirm turn is not enough,
+	// because the whole chain that proposed it — an STT guess, a router guess,
+	// a fuzzy allowlist match — has a spoken "да" as its only check. She names
+	// the gap and he runs it himself.
+	TierIrreversible Risk = "irreversible"
+)
+
+// Policy — what a tier requires of the act path.
+//
+// There is deliberately no "sticky for" field. Non-stickiness is the policy,
+// and a knob that could turn it off would be the thing to argue with instead
+// of the rule.
+type Policy struct {
+	// Confirm — the act does not run on first hearing.
+	Confirm bool
+	// VoiceMayRun — a spoken confirmation is enough authority to run it.
+	VoiceMayRun bool
+}
+
+// PolicyFor returns the requirements of a tier. An unknown tier is treated as
+// destructive, for the same reason the default derivation is.
+func PolicyFor(r Risk) Policy {
+	switch r {
+	case TierSafe:
+		return Policy{Confirm: false, VoiceMayRun: true}
+	case TierIrreversible:
+		return Policy{Confirm: true, VoiceMayRun: false}
+	default:
+		return Policy{Confirm: true, VoiceMayRun: true}
+	}
+}
+
+// irreversibleVerbs — argv heads and subcommands that destroy the thing they
+// name. Matched as whole argv elements, never as substrings: "rm" must not
+// fire on "/usr/bin/rmdir-report" and "drop" must not fire on "dropbox".
+//
+// The list is short on purpose. It is not a sandbox and it does not try to be
+// one — an enabled row can already run anything the daemon's user can run.
+// What it is, is the set of words that mean "and then it is gone", so that the
+// one act nobody can walk back is the one act a spoken "да" cannot authorise.
+var irreversibleVerbs = map[string]bool{
+	"rm": true, "rmdir": true, "shred": true, "srm": true,
+	"mkfs": true, "fdisk": true, "parted": true, "wipefs": true,
+	"dd": true, "format": true,
+	"drop": true, "drop-database": true, "destroy": true, "purge": true,
+	"prune": true, "truncate": true,
+}
+
+// RiskOf derives the tier of an enabled tool row.
+func RiskOf(t ipc.Tool) Risk {
+	if isIrreversible(t.Cmd) {
+		return TierIrreversible
+	}
+	// A house row is a physical change to the flat, and the confirm turn on it
+	// is structural rather than a column: /tools writes the checkbox straight
+	// through on enable, so unticking it once turned an unlock into a row that
+	// ran on first hearing. Nothing any surface writes removes the second turn
+	// from a physical device.
+	if _, _, ok := smarthome.ParseCmd(t.Cmd); ok {
+		return TierDestructive
+	}
+	// An MCP row is a call to somebody else's server. It is enabled with a
+	// fingerprint of what it declared at approval time (Vikunja #251), and the
+	// tier tracks the same flag every other row uses — the point of this branch
+	// is that it is NOT special-cased into running freely.
+	if _, _, ok := mcp.ParseCmd(t.Cmd); ok {
+		if t.Destructive {
+			return TierDestructive
+		}
+		return TierSafe
+	}
+	if t.Destructive {
+		return TierDestructive
+	}
+	if len(t.Cmd) == 0 {
+		// Not a shape this file knows how to read. The default is the confirm
+		// turn: a new domain argues its way down, not up.
+		return TierDestructive
+	}
+	return TierSafe
+}
+
+// isIrreversible reports whether any argv element is one of the verbs that
+// destroys what it names. Every element, not just the head: "sudo rm" and
+// "docker volume prune" both hide the verb behind a wrapper.
+func isIrreversible(cmd []string) bool {
+	for _, arg := range cmd {
+		word := strings.ToLower(strings.TrimSpace(arg))
+		// Take the last path element, so /bin/rm reads as rm.
+		if i := strings.LastIndex(word, "/"); i >= 0 {
+			word = word[i+1:]
+		}
+		if irreversibleVerbs[word] {
+			return true
+		}
+	}
+	return false
+}

internal/tool/risk_test.go

@@ -0,0 +1,81 @@
+package tool
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/kami/maven/internal/ipc"
+)
+
+func TestRiskOfReadsTheRow(t *testing.T) {
+	cases := []struct {
+		name string
+		tool ipc.Tool
+		want Risk
+	}{
+		{"a plain read", ipc.Tool{Cmd: []string{"systemctl", "status"}}, TierSafe},
+		{"the checkbox", ipc.Tool{Cmd: []string{"systemctl", "restart"}, Destructive: true}, TierDestructive},
+		{"a wipe", ipc.Tool{Cmd: []string{"rm", "-rf"}}, TierIrreversible},
+		{"a wipe behind a wrapper", ipc.Tool{Cmd: []string{"sudo", "/bin/rm"}}, TierIrreversible},
+		{"a prune behind a subcommand", ipc.Tool{Cmd: []string{"docker", "volume", "prune"}}, TierIrreversible},
+		{"the house", ipc.Tool{Cmd: []string{"smarthome", "light.kitchen", "turn_off"}}, TierDestructive},
+		{"the house with the box unticked", ipc.Tool{Cmd: []string{"smarthome", "lock.front", "unlock"}}, TierDestructive},
+		{"an mcp read", ipc.Tool{Cmd: []string{"mcp", "vikunja", "list_tasks"}}, TierSafe},
+		{"an mcp write", ipc.Tool{Cmd: []string{"mcp", "vikunja", "delete_task"}, Destructive: true}, TierDestructive},
+		{"a shape nobody wrote yet", ipc.Tool{}, TierDestructive},
+	}
+	for _, c := range cases {
+		if got := RiskOf(c.tool); got != c.want {
+			t.Errorf("%s: RiskOf = %q; want %q", c.name, got, c.want)
+		}
+	}
+}
+
+// The default is the confirm turn. A tier this file does not know is not a
+// tier that runs freely.
+func TestPolicyForDefaultsToConfirming(t *testing.T) {
+	for _, r := range []Risk{TierDestructive, Risk("whatever-lands-here-next")} {
+		p := PolicyFor(r)
+		if !p.Confirm || !p.VoiceMayRun {
+			t.Errorf("PolicyFor(%q) = %+v; want a confirm turn she may run", r, p)
+		}
+	}
+	if p := PolicyFor(TierSafe); p.Confirm || !p.VoiceMayRun {
+		t.Errorf("PolicyFor(safe) = %+v; want it to run", p)
+	}
+	if p := PolicyFor(TierIrreversible); !p.Confirm || p.VoiceMayRun {
+		t.Errorf("PolicyFor(irreversible) = %+v; want voice refused", p)
+	}
+}
+
+// An irreversible act is refused whether or not he said "да", because there is
+// no second answer that changes what it would do.
+func TestExecRefusesIrreversibleEvenConfirmed(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"wipe": {Name: "wipe", Status: "enabled", Cmd: []string{"rm", "-rf"}, Destructive: true},
+	}}
+	e := NewExecutor(api, 0)
+	ran := false
+	e.run = func(context.Context, []string) (string, error) { ran = true; return "", nil }
+	for _, confirmed := range []bool{false, true} {
+		if _, err := e.Exec(context.Background(), "wipe", []string{"/data"}, confirmed); !errors.Is(err, ErrNeedsAuthedSurface) {
+			t.Errorf("confirmed=%v: %v; want ErrNeedsAuthedSurface", confirmed, err)
+		}
+	}
+	if ran {
+		t.Fatal("an irreversible act ran from the voice path")
+	}
+}
+
+// A row with no cmd at all is not a shape this file reads, and it must not
+// slide through as safe.
+func TestExecConfirmsAnUnreadableRow(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"mystery": {Name: "mystery", Status: "enabled"},
+	}}
+	e := NewExecutor(api, 0)
+	if _, err := e.Exec(context.Background(), "mystery", nil, false); !errors.Is(err, ErrNeedsConfirm) {
+		t.Errorf("%v; want ErrNeedsConfirm", err)
+	}
+}

internal/tool/tool.go

@@ -67,6 +67,12 @@ var (
 	// proposal, and drafting a new proposal for a tool that already exists and
 	// is enabled is a lie about what is wrong.
 	ErrNotConnected = errors.New("tool is enabled but its backend is not connected")
+	// ErrNeedsAuthedSurface — the row is enabled and the act is understood,
+	// and its tier is one a spoken "да" may not authorise (risk.go,
+	// TierIrreversible). Held apart from ErrNeedsConfirm because there is no
+	// 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")
 )
 
 // MCPCaller is the seam for an act that is an MCP tool call rather than a
@@ -121,7 +127,12 @@ func (e *Executor) WithHome(h HomeCaller) *Executor {
 // Exec looks up name in the store and runs Cmd+args as argv (no shell).
 // confirmed=true is the second turn of a destructive act (the user said "да");
 // it bypasses the ErrNeedsConfirm gate. Non-enabled ⇒ ErrNotEnabled; a
-// destructive tool with confirmed=false ⇒ ErrNeedsConfirm.
+// destructive tool with confirmed=false ⇒ ErrNeedsConfirm; an irreversible one
+// ⇒ ErrNeedsAuthedSurface, confirmed or not.
+//
+// Exec IS the voice path. Nothing else calls it, which is why the tier check
+// needs no surface argument: the authority it can offer a tool is a spoken
+// "да", and TierIrreversible says that is not enough.
 func (e *Executor) Exec(ctx context.Context, name string, args []string, confirmed bool) (string, error) {
 	t, err := e.api.LookupTool(ctx, name)
 	if errors.Is(err, ipc.ErrToolNotFound) {
@@ -133,7 +144,15 @@ func (e *Executor) Exec(ctx context.Context, name string, args []string, confirm
 	if t.Status != "enabled" {
 		return "", ErrNotEnabled
 	}
-	if t.Destructive && !confirmed {
+	// 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
+	// unrecognised shape inherits (the confirm turn).
+	policy := PolicyFor(RiskOf(t))
+	if !policy.VoiceMayRun {
+		return "", ErrNeedsAuthedSurface
+	}
+	if policy.Confirm && !confirmed {
 		return "", ErrNeedsConfirm
 	}
 	// An MCP row is a call to a configured server, not a process. Everything