Expose discovered MCP tools through the act allowlist (#251)

Second half of the MCP client: the tools the manager discovers become rows in
the existing act allowlist instead of a parallel capability system.

An MCP tool is encoded in the columns that already exist — cmd
["mcp",<server>,<tool>], scope mcp:<server> — so no migration, and
ProposeTool/EnableTool/DisableTool, tool.Matcher and the confirm turn need no
changes. One branch in Executor.Exec routes such a row to the manager instead
of exec, and "mcp" is never run as a binary.

Discovery only ever PROPOSES. destructive comes from the inverse of the MCP
readOnlyHint, so a tool that does not promise to be read-only inherits the
confirm turn, and enabling stays on /tools behind step-up.

Voice args are positional and MCP args are named, so CallPositional binds only
what it can defend: no required properties runs bare, and a read-only tool with
exactly one required string or number gets the tail. Everything else refuses
with ErrNeedsArgs rather than guessing. The read-only condition was learned
against the live Vikunja server: update_task requires only task_id and takes
the rest as optional, so one guessed argument blanked the fields it did not
mention. A partially-filled write destroys what it omits, so a mutating tool
never receives a guessed argument.

Also: a read-only mcp_servers IPC method and an "MCP servers" card on /tools
showing transport, target and state, with the trust level of a local target
spelled out. There is deliberately no call-a-tool IPC method and no run button,
so mutation keeps exactly one path.

Vikunja #251

cmd/mavend/actions_act.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"log"
 
+	"github.com/kami/maven/internal/mcp"
 	"github.com/kami/maven/internal/router"
 	"github.com/kami/maven/internal/tool"
 )
@@ -52,6 +53,12 @@ func (h *reactiveHandler) actionAct(ctx context.Context, dec router.Decision) st
 			return "выполнить «" + phrase + "»? скажи «да» или «нет»."
 		case errors.Is(err, tool.ErrNotEnabled):
 			return h.proposeGap(ctx, dec)
+		case errors.Is(err, mcp.ErrNeedsArgs):
+			// An MCP tool that wants named arguments a spoken verb cannot
+			// supply. Guessing them would be a wrong act, so she says so
+			// instead — the tool is still runnable from the authed surface,
+			// where a human types them.
+			return "этому инструменту нужны аргументы, которые я из голоса не соберу — я не буду угадывать."
 		}
 		log.Printf("voice: tool %s: %v", dec.Slots.Fn, err)
 		if out != "" {

cmd/mavend/main.go

@@ -280,6 +280,9 @@ func run(args []string) error {
 			api := coreAPI.(*daemonAPI)
 			api.chatFn = voiceW.handler.handleText
 		}
+		if voiceW != nil && voiceW.mcp != nil {
+			coreAPI.(*daemonAPI).getMCPServers = voiceW.mcp.status
+		}
 	} else {
 		// locked mode: no real store yet, so there's no meaningful CoreAPI to
 		// serve. srv.Check below is the actual guard — every CoreAPI call is
@@ -518,6 +521,11 @@ func run(args []string) error {
 				}()
 			}
 
+			// Keep MCP connections alive (nil unless configured).
+			if voiceW != nil && voiceW.mcp != nil {
+				go voiceW.mcp.run(ctx)
+			}
+
 			dl.unlock()
 			log.Printf("mavend: unlocked via passkey assertion")
 			return nil
@@ -577,6 +585,13 @@ func run(args []string) error {
 				crawlWkr.run(ctx)
 			}()
 		}
+		if voiceW != nil && voiceW.mcp != nil {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				voiceW.mcp.run(ctx)
+			}()
+		}
 	}
 
 	<-ctx.Done()

cmd/mavend/mcp.go

@@ -0,0 +1,154 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/kami/maven/internal/config"
+	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/mcp"
+	"github.com/kami/maven/internal/store"
+	"github.com/kami/maven/internal/webfetch"
+)
+
+// mcpRefreshInterval — how often the manager re-dials a server that is down.
+// The manager applies its own backoff on top, so this being short is cheap.
+const mcpRefreshInterval = time.Minute
+
+// mcpWiring — the MCP client, when the `mcp` block configures at least one
+// enabled server. nil ⇒ nothing was configured, nothing is connected, and an
+// allowlist row that happens to look like an MCP row refuses to run.
+//
+// It lives on the voice wiring because MCP tools ARE acts: they run through
+// tool.Executor, the enabled allowlist and the confirm turn, which only exist
+// on the voice/chat path. No voice surface ⇒ nothing that could call a tool.
+type mcpWiring struct {
+	mgr *mcp.Manager
+	st  *store.Store
+}
+
+// wireMCP builds the manager, connects, and proposes what it found. It never
+// fails the daemon: a server that is unreachable at boot is logged and retried,
+// because Maven starting is not contingent on someone else's process.
+func wireMCP(cfg *config.Config, st *store.Store) *mcpWiring {
+	servers := cfg.MCPServers()
+	if len(servers) == 0 {
+		return nil
+	}
+	limits := webfetch.Config{}
+	if cfg.MCP != nil {
+		limits.AllowHosts = cfg.MCP.AllowHosts
+		limits.DenyHosts = cfg.MCP.DenyHosts
+		limits.MaxBytes = cfg.MCP.MaxBytes
+		limits.Timeout = time.Duration(cfg.MCP.Timeout)
+	}
+	mgr, err := mcp.NewManager(mcp.WebfetchDoor(limits), servers)
+	if err != nil {
+		// Validation already ran in config.validate, so this is a programming
+		// error rather than a config one. Still not fatal: MCP off is a working
+		// Maven.
+		log.Printf("mcp: not wired: %v", err)
+		return nil
+	}
+	w := &mcpWiring{mgr: mgr, st: st}
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	mgr.Connect(ctx)
+	w.propose(ctx)
+	return w
+}
+
+// propose writes a 'proposed' allowlist row for every discovered tool. It does
+// NOT enable anything: a configured server is a place Maven may look, not a
+// capability she has. Kami enables what he wants on /tools, behind step-up,
+// which is the same gate a shell tool goes through.
+//
+// Re-running on every boot is idempotent — ProposeMCPTool never touches an
+// existing row, so a tool he disabled stays disabled and one he enabled keeps
+// the cmd he enabled it with.
+func (w *mcpWiring) propose(ctx context.Context) {
+	if w == nil {
+		return
+	}
+	now := time.Now()
+	fresh := 0
+	for _, t := range w.mgr.Tools() {
+		name := mcp.LocalName(t.Server, t.Name)
+		// No readOnlyHint ⇒ assume it mutates ⇒ the confirm turn. Being wrong
+		// in this direction only costs a question.
+		destructive := !t.ReadOnly
+		provenance := fmt.Sprintf("mcp %s/%s", t.Server, t.Name)
+		if t.Description != "" {
+			provenance += ": " + t.Description
+		}
+		ok, err := w.st.ProposeMCPTool(ctx, name, mcp.Scope(t.Server),
+			mcp.Cmd(t.Server, t.Name), destructive, provenance, now)
+		if err != nil {
+			log.Printf("mcp: propose %s: %v", name, err)
+			continue
+		}
+		if ok {
+			fresh++
+		}
+	}
+	if fresh > 0 {
+		log.Printf("mcp: %d new tool proposal(s) waiting on /tools", fresh)
+	}
+}
+
+// run re-dials downed servers and picks up tools that appeared, until ctx is
+// canceled.
+func (w *mcpWiring) run(ctx context.Context) {
+	if w == nil {
+		return
+	}
+	t := time.NewTicker(mcpRefreshInterval)
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-t.C:
+			w.mgr.Refresh(ctx)
+			w.propose(ctx)
+		}
+	}
+}
+
+// status maps the manager's view onto the wire type the web surface reads.
+func (w *mcpWiring) status() []ipc.MCPServerStatus {
+	if w == nil {
+		return nil
+	}
+	in := w.mgr.Status()
+	out := make([]ipc.MCPServerStatus, 0, len(in))
+	for _, s := range in {
+		out = append(out, ipc.MCPServerStatus{
+			Name:      s.Name,
+			Transport: s.Transport,
+			Target:    s.Target,
+			Connected: s.Connected,
+			Server:    s.Server,
+			Tools:     s.Tools,
+			Err:       s.Err,
+		})
+	}
+	return out
+}
+
+func (w *mcpWiring) close() {
+	if w == nil {
+		return
+	}
+	_ = w.mgr.Close()
+}
+
+// caller is the tool.MCPCaller the executor gets, or nil when MCP is off.
+func (w *mcpWiring) caller() *mcp.Manager {
+	if w == nil {
+		return nil
+	}
+	return w.mgr
+}

cmd/mavend/mcp_test.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/kami/maven/internal/config"
+)
+
+func TestWireMCPOffWhenUnconfigured(t *testing.T) {
+	st := newTestStore(t)
+	for name, cfg := range map[string]*config.Config{
+		"no block": {},
+		"nothing enabled": {MCP: &config.MCPConfig{Servers: []config.MCPServerConfig{
+			{Name: "vikunja", URL: "http://192.168.1.104:9100/mcp"},
+		}}},
+	} {
+		t.Run(name, func(t *testing.T) {
+			if w := wireMCP(cfg, st); w != nil {
+				t.Fatal("MCP must be off unless a server is configured AND enabled")
+			}
+		})
+	}
+	// nil wiring must be safe to use everywhere it is reachable.
+	var w *mcpWiring
+	w.close()
+	w.propose(context.Background())
+	if w.status() != nil || w.caller() != nil {
+		t.Fatal("a nil wiring must report nothing")
+	}
+}
+
+// An unreachable server must not stop the daemon, must be reported as down, and
+// must propose nothing.
+func TestWireMCPUnreachableServerIsNotFatal(t *testing.T) {
+	st := newTestStore(t)
+	w := wireMCP(&config.Config{MCP: &config.MCPConfig{Servers: []config.MCPServerConfig{{
+		Name: "dead", Command: "/nonexistent/mcp-server", Enabled: true,
+	}}}}, st)
+	if w == nil {
+		t.Fatal("a configured server should still wire")
+	}
+	defer w.close()
+	st2 := w.status()
+	if len(st2) != 1 || st2[0].Connected || st2[0].Err == "" {
+		t.Fatalf("status = %+v", st2)
+	}
+	tools, err := st.ListTools(context.Background(), "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(tools) != 0 {
+		t.Fatalf("a server that never answered must propose nothing, got %+v", tools)
+	}
+}
+
+// A url server whose address is private is refused by webfetch unless that
+// server sets allow_private. This is the guard the whole MCP path rides on, so
+// it is asserted here too, at the wiring level.
+func TestWireMCPPrivateURLRefusedWithoutAllowPrivate(t *testing.T) {
+	st := newTestStore(t)
+	w := wireMCP(&config.Config{MCP: &config.MCPConfig{Servers: []config.MCPServerConfig{{
+		Name: "lan", URL: "http://127.0.0.1:9100/mcp", Enabled: true,
+	}}}}, st)
+	if w == nil {
+		t.Fatal("should wire")
+	}
+	defer w.close()
+	s := w.status()[0]
+	if s.Connected {
+		t.Fatal("a loopback server must not connect without allow_private")
+	}
+	if !strings.Contains(s.Err, "private address") {
+		t.Fatalf("err = %q, want the private-address refusal", s.Err)
+	}
+}

cmd/mavend/tick.go

@@ -941,6 +941,7 @@ type daemonAPI struct {
 	getMorningStatus func(ctx context.Context) []ipc.MorningRoutineStatus
 	getDayPlan       func(ctx context.Context) ipc.DayPlan
 	chatFn           func(ctx context.Context, text string) string
+	getMCPServers    func() []ipc.MCPServerStatus
 }
 
 func (d *daemonAPI) Chat(ctx context.Context, text string) (string, error) {
@@ -950,6 +951,16 @@ func (d *daemonAPI) Chat(ctx context.Context, text string) (string, error) {
 	return d.chatFn(ctx, text), nil
 }
 
+// MCPServers — the configured MCP servers and their health (Vikunja #251).
+// Empty, not an error, when the mcp block is absent: "not configured" is the
+// default state and the web surface renders it as such.
+func (d *daemonAPI) MCPServers(ctx context.Context) ([]ipc.MCPServerStatus, error) {
+	if d.getMCPServers == nil {
+		return nil, nil
+	}
+	return d.getMCPServers(), nil
+}
+
 func (d *daemonAPI) TickTrace(ctx context.Context) (ipc.TickTrace, error) {
 	trace := d.getTrace()
 	if trace == nil {

cmd/mavend/voicewire.go

@@ -40,6 +40,10 @@ type voiceWiring struct {
 	// mavsttd / mavttsd don't keep a stale conn into a restarting daemon.
 	sttClient *worker.Client
 	ttsClient *worker.Client
+	// mcp — the MCP client, nil unless the `mcp` block configures an enabled
+	// server (Vikunja #251). Its tools land in the same allowlist as every
+	// other act, so nothing else here has to know about it.
+	mcp *mcpWiring
 }
 
 // close releases the listener + worker conns. Safe to call on nil (when
@@ -60,6 +64,7 @@ func (w *voiceWiring) close() {
 	if w.ttsClient != nil {
 		_ = w.ttsClient.Close()
 	}
+	w.mcp.close()
 }
 
 // wireVoice builds the audio path from cfg + a CoreAPI + a router. Returns
@@ -131,6 +136,14 @@ func wireVoice(cfg *config.Config, coreAPI ipc.CoreAPI, phr phraser.Phraser, mem
 	// daemon restart.
 	seedTools(coreAPI, cfg.Voice.Tools)
 	exec := tool.NewExecutor(coreAPI, time.Duration(cfg.Voice.ToolTimeout))
+	// MCP servers (Vikunja #251): discovery PROPOSES tools into the same
+	// allowlist, so an MCP tool is enabled by hand on /tools like any other and
+	// runs through the same confirm turn. Off unless the `mcp` block configures
+	// an enabled server.
+	w.mcp = wireMCP(cfg, dataStore)
+	if w.mcp != nil {
+		exec = exec.WithMCP(w.mcp.caller())
+	}
 	matcher := tool.NewMatcher(coreAPI)
 
 	// ----- weather provider (Open-Meteo when configured, Stub otherwise) -----

cmd/mavweb/handlers_test.go

@@ -67,6 +67,14 @@ type fakeCore struct {
 	// for handleChatAPI tests
 	chatText string
 	chatErr  error
+
+	// for the MCP section of /tools
+	mcpServers []ipc.MCPServerStatus
+	mcpErr     error
+}
+
+func (f *fakeCore) MCPServers(context.Context) ([]ipc.MCPServerStatus, error) {
+	return f.mcpServers, f.mcpErr
 }
 
 func (f *fakeCore) Chat(_ context.Context, text string) (string, error) {
@@ -1118,3 +1126,49 @@ func TestHandleChatAPI_FailOpenByDefault(t *testing.T) {
 		t.Errorf("core.Chat text = %q, want %q", core.chatText, "привет")
 	}
 }
+
+// The MCP section renders the configured servers, and a proposal that already
+// knows its cmd prefills the enable form so the argv is not retyped by hand.
+func TestHandleTools_GET_MCPSection(t *testing.T) {
+	core := &fakeCore{
+		proposed: []ipc.Tool{{
+			Name: "vikunja_list_tasks", Scope: "mcp:vikunja",
+			Cmd: []string{"mcp", "vikunja", "list_tasks"}, Destructive: true,
+			Utterance: "mcp vikunja/list_tasks: List tasks in a project.",
+		}},
+		mcpServers: []ipc.MCPServerStatus{
+			{Name: "vikunja", Transport: "http", Target: "http://192.168.1.104:9100/mcp", Connected: true, Server: "vikunja 0.1.0", Tools: 4},
+			{Name: "files", Transport: "stdio", Target: "mcp-server-fs /srv", Err: "start: no such file"},
+		},
+	}
+	rr := httptest.NewRecorder()
+	handleTools(rr, httptest.NewRequest(http.MethodGet, "/tools", nil), core, nil, false)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("status = %d", rr.Code)
+	}
+	body := rr.Body.String()
+	for _, want := range []string{
+		"MCP servers", "vikunja", "192.168.1.104:9100/mcp", "vikunja 0.1.0",
+		"files", "no such file",
+		`value="mcp vikunja list_tasks"`, // the enable form is prefilled
+		"checked",                        // and pre-marked destructive (no readOnlyHint)
+	} {
+		if !strings.Contains(body, want) {
+			t.Errorf("missing %q in /tools output", want)
+		}
+	}
+}
+
+// MCP off (or an older core that does not know the method) renders the section
+// empty instead of breaking the page.
+func TestHandleTools_GET_MCPUnavailable(t *testing.T) {
+	core := &fakeCore{mcpErr: ipc.ErrNotImplemented}
+	rr := httptest.NewRecorder()
+	handleTools(rr, httptest.NewRequest(http.MethodGet, "/tools", nil), core, nil, false)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200", rr.Code)
+	}
+	if !strings.Contains(rr.Body.String(), "no MCP servers configured") {
+		t.Error("expected the empty-state copy")
+	}
+}

cmd/mavweb/main.go

@@ -692,7 +692,7 @@ const toolsHTML = `{{template "shellTop" "tools"}}
 {{if .Msg}}<div class="msg msg-ok">{{.Msg}}</div>{{end}}
 <section class=card>
 <h2 class=card-title>proposed <span class=badge>{{len .Proposed}}</span></h2>
-{{if .Proposed}}<p class=hint>maven drafted these from acts she couldn't run. Fill the command (argv, space-separated) and enable.</p>
+{{if .Proposed}}<p class=hint>maven drafted these from acts she couldn't run. Fill the command (argv, space-separated) and enable. A row in an <code>mcp:</code> scope came from an MCP server and already knows what it calls — check the command, then enable.</p>
 <div class=scroll><table><tr><th>name</th><th>scope</th><th>from utterance</th><th>enable as</th></tr>
 {{range .Proposed}}<tr>
 <td><code>{{.Name}}</code></td><td><span class=badge>{{.Scope}}</span></td><td>{{.Utterance}}</td>
@@ -700,8 +700,8 @@ const toolsHTML = `{{template "shellTop" "tools"}}
 <input type=hidden name=name value="{{.Name}}">
 <input type=hidden name=scope value="{{.Scope}}">
 <input type=hidden name=action value=enable>
-<input type=text name=cmd class=input-wide placeholder="systemctl restart" required>
-<label><input type=checkbox name=destructive> destructive</label>
+<input type=text name=cmd class=input-wide placeholder="systemctl restart" value="{{join .Cmd " "}}" required>
+<label><input type=checkbox name=destructive {{if .Destructive}}checked{{end}}> destructive</label>
 <button class=btn>enable</button></form>
 <form method=post action=/tools class=inline-form>
 <input type=hidden name=name value="{{.Name}}">
@@ -730,6 +730,19 @@ const toolsHTML = `{{template "shellTop" "tools"}}
   <div class=hint>enable proposed tools above, or ask maven to configure one</div>
 </div>{{end}}
 </section>
+<section class=card>
+<h2 class=card-title>MCP servers <span class=badge>{{len .MCP}}</span></h2>
+{{if .MCP}}<p class=hint>servers she connects OUT to. Their tools appear above as proposals — a configured server is a place she may look, not a capability she has. A <code>stdio</code> target is a process on this box; an <code>http</code> one on a loopback or LAN address is inside the network, so treat its tools accordingly.</p>
+<div class=scroll><table><tr><th>name</th><th>transport</th><th>target</th><th>state</th><th>tools</th></tr>
+{{range .MCP}}<tr><td><code>{{.Name}}</code></td><td><span class=badge>{{.Transport}}</span></td><td><code>{{.Target}}</code></td>
+<td>{{if .Connected}}connected{{if .Server}} — {{.Server}}{{end}}{{else}}<span class=red>down</span>{{if .Err}} — {{.Err}}{{end}}{{end}}</td>
+<td>{{.Tools}}</td></tr>{{end}}</table></div>
+{{else}}<div class=empty>
+  <svg class=icon width="20" height="20"><use href="/ethos-icons.svg#i-settings"/></svg>
+  <div>no MCP servers configured</div>
+  <div class=hint>add an <code>mcp.servers</code> block to mavend.json to let her use an external tool server</div>
+</div>{{end}}
+</section>
 {{template "shellBottom"}}`
 
 // routinesHTML — proposed routine review surface. One row per thing maven
@@ -1320,12 +1333,20 @@ func handleTools(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI, sessi
 		http.Error(w, "core read failed", http.StatusBadGateway)
 		return
 	}
+	// MCP is off by default and an older core may not know the method at all,
+	// so a failure here renders an empty section rather than breaking the page.
+	servers, err := core.MCPServers(ctx)
+	if err != nil {
+		log.Printf("tools: mcp servers: %v", err)
+		servers = nil
+	}
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	if err := toolsTmpl.Execute(w, struct {
 		Msg      string
 		Proposed []ipc.Tool
 		Enabled  []ipc.Tool
-	}{msg, proposed, enabled}); err != nil {
+		MCP      []ipc.MCPServerStatus
+	}{msg, proposed, enabled, servers}); err != nil {
 		log.Printf("tools render: %v", err)
 	}
 }

deploy/mavend.json

@@ -31,6 +31,20 @@
     "cooldown": "24h"
   },
 
+  "mcp": {
+    "timeout": "15s",
+    "servers": [
+      {
+        "name": "vikunja",
+        "url": "http://192.168.1.104:9100/mcp",
+        "allow_private": true,
+        "allow_tools": ["list_projects", "list_tasks", "get_task_details", "create_task"],
+        "max_tools": 6,
+        "enabled": false
+      }
+    ]
+  },
+
   "nexus":  { "url": "http://nexus:9740" },
   "praxis": { "url": "http://praxis:8989" },
   "hexis":  { "url": "http://hexis:9741" },

internal/ipc/api.go

@@ -319,6 +319,19 @@ type Tool struct {
 	Updated     time.Time `json:"updated"`
 }
 
+// MCPServerStatus — one configured MCP server, as the web surface sees it.
+// Target is the command or url; Tools is how many tools discovery kept after
+// allow_tools / max_tools, not how many the server offers.
+type MCPServerStatus struct {
+	Name      string `json:"name"`
+	Transport string `json:"transport"` // "stdio" (a local subprocess) or "http"
+	Target    string `json:"target"`
+	Connected bool   `json:"connected"`
+	Server    string `json:"server,omitempty"` // the server's own name + version
+	Tools     int    `json:"tools"`
+	Err       string `json:"err,omitempty"`
+}
+
 // chatReq / chatResp — text chat round-trip for the IPC Chat method.
 type chatReq struct {
 	Text string `json:"text"`
@@ -457,6 +470,14 @@ type CoreAPI interface {
 	// TickTrace.
 	MorningStatus(ctx context.Context) ([]MorningRoutineStatus, error)
 
+	// MCPServers reports the configured MCP servers and their health
+	// (Vikunja #251). Read-only introspection for /tools — there is no
+	// "call this tool" method on purpose: an MCP tool runs through the same
+	// allowlist, confirm turn and act path as any other tool, and a second
+	// mutation path would be a second thing to get wrong. Empty when the
+	// mcp config block is absent, which is the default.
+	MCPServers(ctx context.Context) ([]MCPServerStatus, error)
+
 	// DayPlan returns today's ordered plan — calendar events, pending
 	// reminders and any morning checklist still outstanding (see
 	// internal/morning.BuildPlan) — plus the spoken RU rendering of it.

internal/ipc/client.go

@@ -72,6 +72,7 @@ var readOnlyMethods = map[Method]bool{
 	MethodListTasks:            true,
 	MethodTickTrace:            true,
 	MethodMorningStatus:        true,
+	MethodMCPServers:           true,
 	MethodDayPlan:              true,
 }
 
@@ -505,6 +506,14 @@ func (c *Client) TickTrace(ctx context.Context) (TickTrace, error) {
 	return t, nil
 }
 
+func (c *Client) MCPServers(ctx context.Context) ([]MCPServerStatus, error) {
+	var s []MCPServerStatus
+	if err := c.call(ctx, MethodMCPServers, nil, &s); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
 func (c *Client) MorningStatus(ctx context.Context) ([]MorningRoutineStatus, error) {
 	var s []MorningRoutineStatus
 	if err := c.call(ctx, MethodMorningStatus, nil, &s); err != nil {

internal/ipc/server.go

@@ -211,6 +211,10 @@ func (a *storeAPI) MorningStatus(ctx context.Context) ([]MorningRoutineStatus, e
 	return nil, errors.New("store: morning status not available via direct store API")
 }
 
+func (a *storeAPI) MCPServers(ctx context.Context) ([]MCPServerStatus, error) {
+	return nil, nil // no manager behind a bare store: nothing configured
+}
+
 func (a *storeAPI) DayPlan(ctx context.Context) (DayPlan, error) {
 	return DayPlan{}, errors.New("store: day plan not available via direct store API")
 }
@@ -832,6 +836,16 @@ var methodTable = map[Method]handlerFunc{
 	MethodMorningStatus: withoutParams(func(ctx context.Context, api CoreAPI) ([]MorningRoutineStatus, error) {
 		return api.MorningStatus(ctx)
 	}),
+	MethodMCPServers: withoutParams(func(ctx context.Context, api CoreAPI) ([]MCPServerStatus, error) {
+		out, err := api.MCPServers(ctx)
+		if err != nil {
+			return nil, err
+		}
+		if out == nil {
+			out = []MCPServerStatus{}
+		}
+		return out, nil
+	}),
 }
 
 // dispatch unmarshals params for req.Method and calls the matching CoreAPI

internal/ipc/unimplemented.go

@@ -122,6 +122,9 @@ func (UnimplementedCoreAPI) TickTrace(ctx context.Context) (TickTrace, error) {
 func (UnimplementedCoreAPI) MorningStatus(ctx context.Context) ([]MorningRoutineStatus, error) {
 	return nil, ErrNotImplemented
 }
+func (UnimplementedCoreAPI) MCPServers(ctx context.Context) ([]MCPServerStatus, error) {
+	return nil, ErrNotImplemented
+}
 func (UnimplementedCoreAPI) DayPlan(ctx context.Context) (DayPlan, error) {
 	return DayPlan{}, ErrNotImplemented
 }

internal/ipc/wire.go

@@ -45,6 +45,7 @@ const (
 	MethodRevertFact             Method = "revert_fact"
 	MethodTickTrace              Method = "tick_trace"
 	MethodMorningStatus          Method = "morning_status"
+	MethodMCPServers             Method = "mcp_servers"
 	MethodDayPlan                Method = "day_plan"
 	MethodChat                   Method = "chat"
 	MethodCaptureTask            Method = "capture_task"

internal/mcp/manager.go

@@ -2,10 +2,12 @@ package mcp
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"log"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -429,3 +431,93 @@ func (m *Manager) Close() error {
 	}
 	return nil
 }
+
+// ErrNeedsArgs — the tool requires arguments that a voice verb cannot supply.
+var ErrNeedsArgs = errors.New("mcp: tool needs named arguments")
+
+// CallPositional is the voice path's way in. The router gives an act a verb and
+// a tail of positional words; an MCP tool wants a named-argument object. There
+// is no general mapping between those two, and inventing one is exactly the
+// improvisation this codebase refuses, so the rule is deliberately narrow:
+//
+//   - a tool with no required properties runs with no arguments (a spare tail
+//     is ignored — "покажи проекты пожалуйста" should still list projects);
+//   - a READ-ONLY tool with exactly one required property, of type string or
+//     integer/number, gets the tail bound to it;
+//   - anything else is refused with ErrNeedsArgs. Such a tool is still callable
+//     with explicit arguments from the authed surface, where a human types
+//     them.
+//
+// The refusal is the point, and the read-only condition on it was learned the
+// hard way while testing against the Vikunja server: `update_task` requires
+// only `task_id` and takes every other field as optional, so calling it with
+// one guessed argument and no others BLANKED the fields it did not receive. A
+// mutating tool therefore never gets a guessed argument — the one thing a
+// partially-filled write can do is destroy what it did not mention. A mutating
+// tool with nothing required is still fine: nothing was guessed, and it still
+// goes through the confirm turn.
+func (m *Manager) CallPositional(ctx context.Context, server, tool string, args []string) (string, error) {
+	m.mu.Lock()
+	c := m.conns[server]
+	var schema json.RawMessage
+	found, readOnly := false, false
+	if c != nil {
+		for _, t := range c.tools {
+			if t.Name == tool {
+				schema, readOnly, found = t.InputSchema, t.ReadOnly, true
+				break
+			}
+		}
+	}
+	m.mu.Unlock()
+	if !found {
+		return "", fmt.Errorf("mcp: %s offers no tool %q", server, tool)
+	}
+	named, err := bindPositional(schema, args, readOnly)
+	if err != nil {
+		return "", err
+	}
+	return m.Call(ctx, server, tool, named)
+}
+
+// bindPositional implements the rule documented on CallPositional.
+func bindPositional(schema json.RawMessage, args []string, readOnly bool) (map[string]any, error) {
+	var s struct {
+		Required   []string `json:"required"`
+		Properties map[string]struct {
+			Type string `json:"type"`
+		} `json:"properties"`
+	}
+	if len(schema) > 0 {
+		if err := json.Unmarshal(schema, &s); err != nil {
+			return nil, fmt.Errorf("mcp: unreadable input schema: %w", err)
+		}
+	}
+	switch len(s.Required) {
+	case 0:
+		return map[string]any{}, nil
+	case 1:
+		name := s.Required[0]
+		if !readOnly {
+			return nil, fmt.Errorf("%w: %q, and a tool that writes never gets a guessed one", ErrNeedsArgs, name)
+		}
+		tail := strings.TrimSpace(strings.Join(args, " "))
+		if tail == "" {
+			return nil, fmt.Errorf("%w: %q", ErrNeedsArgs, name)
+		}
+		switch s.Properties[name].Type {
+		case "string", "":
+			return map[string]any{name: tail}, nil
+		case "integer", "number":
+			n, err := strconv.ParseFloat(tail, 64)
+			if err != nil {
+				return nil, fmt.Errorf("%w: %q wants a number, got %q", ErrNeedsArgs, name, tail)
+			}
+			return map[string]any{name: n}, nil
+		default:
+			return nil, fmt.Errorf("%w: %q is a %s", ErrNeedsArgs, name, s.Properties[name].Type)
+		}
+	default:
+		return nil, fmt.Errorf("%w: %s", ErrNeedsArgs, strings.Join(s.Required, ", "))
+	}
+}

internal/mcp/mcp_test.go

@@ -444,3 +444,122 @@ func TestLocalNameAndCmd(t *testing.T) {
 		t.Error("scope")
 	}
 }
+
+func TestBindPositional(t *testing.T) {
+	cases := []struct {
+		name, schema string
+		args         []string
+		mutating     bool
+		want         map[string]any
+		wantErr      bool
+	}{
+		{
+			name: "no required runs with nothing",
+			// A spare tail is fine: "покажи проекты пожалуйста" still lists them.
+			schema: `{"type":"object","properties":{},"required":[]}`,
+			args:   []string{"пожалуйста"},
+			want:   map[string]any{},
+		},
+		{
+			name:   "empty schema",
+			schema: ``,
+			want:   map[string]any{},
+		},
+		{
+			name:   "one required string gets the tail",
+			schema: `{"properties":{"q":{"type":"string"}},"required":["q"]}`,
+			args:   []string{"почему", "небо", "синее"},
+			want:   map[string]any{"q": "почему небо синее"},
+		},
+		{
+			name:    "one required string with no tail",
+			schema:  `{"properties":{"q":{"type":"string"}},"required":["q"]}`,
+			wantErr: true,
+		},
+		{
+			name:   "one required integer parses",
+			schema: `{"properties":{"task_id":{"type":"integer"}},"required":["task_id"]}`,
+			args:   []string{"251"},
+			want:   map[string]any{"task_id": float64(251)},
+		},
+		{
+			name:    "one required integer with words",
+			schema:  `{"properties":{"task_id":{"type":"integer"}},"required":["task_id"]}`,
+			args:    []string{"двести", "пятьдесят", "один"},
+			wantErr: true,
+		},
+		{
+			name:    "two required is refused rather than guessed",
+			schema:  `{"properties":{"a":{"type":"string"},"b":{"type":"string"}},"required":["a","b"]}`,
+			args:    []string{"что-то"},
+			wantErr: true,
+		},
+		{
+			name:    "one required object is refused",
+			schema:  `{"properties":{"payload":{"type":"object"}},"required":["payload"]}`,
+			args:    []string{"что-то"},
+			wantErr: true,
+		},
+		{
+			// Learned from Vikunja's update_task: required ["task_id"], every
+			// other field optional, so one guessed argument blanks the rest.
+			name:     "one required on a mutating tool is refused",
+			schema:   `{"properties":{"task_id":{"type":"integer"}},"required":["task_id"]}`,
+			args:     []string{"251"},
+			mutating: true,
+			wantErr:  true,
+		},
+		{
+			// Nothing was guessed, so there is nothing to get wrong. It still
+			// goes through the confirm turn upstream.
+			name:     "no required on a mutating tool still runs",
+			schema:   `{"properties":{},"required":[]}`,
+			mutating: true,
+			want:     map[string]any{},
+		},
+		{
+			name:    "unreadable schema",
+			schema:  `not json`,
+			wantErr: true,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := bindPositional(json.RawMessage(tc.schema), tc.args, !tc.mutating)
+			if tc.wantErr {
+				if err == nil {
+					t.Fatalf("want an error, got %v", got)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatal(err)
+			}
+			if fmt.Sprint(got) != fmt.Sprint(tc.want) {
+				t.Fatalf("got %v want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestCallPositionalThroughManager(t *testing.T) {
+	p := &fakePoster{handler: echoServer()}
+	m, err := NewManager(func(ServerConfig) (Poster, error) { return p, nil },
+		[]ServerConfig{{Name: "fake", URL: "http://example.test/mcp", Enabled: true}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	m.Connect(context.Background())
+	defer m.Close()
+	// echoServer's tools declare no required properties.
+	out, err := m.CallPositional(context.Background(), "fake", "read_thing", []string{"хвост"})
+	if err != nil {
+		t.Fatalf("call: %v", err)
+	}
+	if out != "read_thing:<nil>" {
+		t.Fatalf("out = %q", out)
+	}
+	if _, err := m.CallPositional(context.Background(), "fake", "absent", nil); err == nil {
+		t.Error("an unknown tool must be refused")
+	}
+}

internal/store/tools.go

@@ -56,6 +56,45 @@ func (s *Store) ProposeTool(ctx context.Context, name, utterance, scope string,
 	return n > 0, nil
 }
 
+// ProposeMCPTool is ProposeTool for a tool discovered on an MCP server
+// (Vikunja #251): the proposal already knows what it would run, so cmd and
+// destructive are written with it and Kami only has to press enable.
+//
+// It is still a PROPOSAL. Discovery cannot grant a capability — that is the
+// whole reason a server can be configured without its tools becoming live.
+// Like ProposeTool it never touches an existing row, so re-discovery on every
+// restart is idempotent and cannot silently re-arm a tool that was disabled or
+// change the cmd of one already enabled.
+func (s *Store) ProposeMCPTool(ctx context.Context, name, scope string, cmd []string, destructive bool, utterance string, ts time.Time) (bool, error) {
+	if len(cmd) == 0 {
+		return false, ErrToolCmd
+	}
+	if scope == "" {
+		scope = "homelab"
+	}
+	raw, err := json.Marshal(cmd)
+	if err != nil {
+		return false, fmt.Errorf("propose mcp tool: %w", err)
+	}
+	d := 0
+	if destructive {
+		d = 1
+	}
+	res, err := s.db.ExecContext(ctx, `
+		INSERT INTO tools (name, scope, cmd, destructive, status, utterance, created_ts, updated_ts)
+		VALUES (?, ?, ?, ?, 'proposed', ?, ?, ?)
+		ON CONFLICT(name) DO NOTHING`,
+		name, scope, string(raw), d, utterance, ts.UnixMilli(), ts.UnixMilli())
+	if err != nil {
+		return false, fmt.Errorf("propose mcp tool: %w", err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return false, fmt.Errorf("propose mcp tool: rows affected: %w", err)
+	}
+	return n > 0, nil
+}
+
 // EnableTool fills cmd + destructive and flips status to 'enabled'. This is the
 // human "enable" act (the authed surface calls it); it upserts so enabling a
 // name that was never proposed still works. An empty cmd is refused — an

internal/store/tools_test.go

@@ -2,6 +2,7 @@ package store
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 )
@@ -60,3 +61,64 @@ func TestToolLifecycle(t *testing.T) {
 		t.Fatalf("disable absent must be no-op: %v", err)
 	}
 }
+
+// A discovered MCP tool arrives as a proposal that already knows its cmd, so
+// enabling it is one click rather than one retyped argv.
+func TestProposeMCPTool(t *testing.T) {
+	s := newTestStore(t)
+	ctx := context.Background()
+	now := time.Now()
+	cmd := []string{"mcp", "vikunja", "list_tasks"}
+
+	fresh, err := s.ProposeMCPTool(ctx, "vikunja_list_tasks", "mcp:vikunja", cmd, false, "mcp vikunja/list_tasks: List tasks", now)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !fresh {
+		t.Fatal("first proposal should be new")
+	}
+	got, err := s.LookupTool(ctx, "vikunja_list_tasks")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Status != "proposed" {
+		t.Fatalf("status = %q — discovery must never enable", got.Status)
+	}
+	if len(got.Cmd) != 3 || got.Cmd[0] != "mcp" || got.Cmd[2] != "list_tasks" {
+		t.Fatalf("cmd = %v", got.Cmd)
+	}
+	if got.Scope != "mcp:vikunja" || got.Utterance == "" {
+		t.Fatalf("provenance lost: %+v", got)
+	}
+
+	// Re-discovery on the next boot is idempotent.
+	fresh, err = s.ProposeMCPTool(ctx, "vikunja_list_tasks", "mcp:vikunja", cmd, true, "changed", now)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fresh {
+		t.Error("re-proposing an existing row must report nothing new")
+	}
+
+	// And it must not re-arm or rewrite a row a human already acted on.
+	if err := s.EnableTool(ctx, "vikunja_list_tasks", cmd, false, "mcp:vikunja", now); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := s.ProposeMCPTool(ctx, "vikunja_list_tasks", "mcp:vikunja", []string{"mcp", "vikunja", "delete_task"}, true, "x", now); err != nil {
+		t.Fatal(err)
+	}
+	got, err = s.LookupTool(ctx, "vikunja_list_tasks")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Status != "enabled" || got.Cmd[2] != "list_tasks" || got.Destructive {
+		t.Fatalf("an enabled row was modified by discovery: %+v", got)
+	}
+}
+
+func TestProposeMCPToolNeedsCmd(t *testing.T) {
+	s := newTestStore(t)
+	if _, err := s.ProposeMCPTool(context.Background(), "x", "mcp:y", nil, false, "", time.Now()); !errors.Is(err, ErrToolCmd) {
+		t.Fatalf("err = %v, want ErrToolCmd", err)
+	}
+}

internal/tool/tool.go

@@ -13,6 +13,11 @@
 //   - Args are passed as argv, NEVER through a shell. STT text lands as
 //     positional arguments to Cmd; there is no `sh -c`, so "restart nginx;
 //     rm -rf" can't inject — the tail is one argv element to the named binary.
+//   - An enabled row whose cmd is ["mcp", "<server>", "<tool>"] is a call to a
+//     configured MCP server instead of a process (Vikunja #251). It goes
+//     through every rule above unchanged — enabled, and confirmed if it
+//     mutates — because the store is still the allowlist; only the dispatch at
+//     the bottom of Exec differs.
 //   - Destructive tools don't run on first hearing: Exec returns ErrNeedsConfirm
 //     and the handler runs a confirm turn ("выполнить X? да/нет"); only a
 //     confirmed re-Exec runs them. A gate assumes a fully-formed action, which
@@ -31,6 +36,7 @@ import (
 	"time"
 
 	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/mcp"
 	"github.com/kami/maven/internal/router"
 )
 
@@ -50,12 +56,21 @@ var (
 	ErrNeedsConfirm = errors.New("destructive tool needs confirmation")
 )
 
+// 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
+// silently doing nothing.
+type MCPCaller interface {
+	CallPositional(ctx context.Context, server, tool string, args []string) (string, error)
+}
+
 // Executor runs enabled tools. run is the exec seam (default: real process);
 // tests swap it. timeout bounds each invocation.
 type Executor struct {
 	api     API
 	timeout time.Duration
 	run     func(ctx context.Context, argv []string) (string, error)
+	mcp     MCPCaller
 }
 
 // NewExecutor builds the executor. timeout<=0 defaults to 30s.
@@ -66,6 +81,13 @@ func NewExecutor(api API, timeout time.Duration) *Executor {
 	return &Executor{api: api, timeout: timeout, run: runProcess}
 }
 
+// WithMCP attaches the MCP caller. Called once at wiring time when the mcp
+// config block is present; without it, a row whose cmd is ["mcp", …] refuses.
+func (e *Executor) WithMCP(m MCPCaller) *Executor {
+	e.mcp = m
+	return e
+}
+
 // 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
@@ -84,6 +106,17 @@ func (e *Executor) Exec(ctx context.Context, name string, args []string, confirm
 	if t.Destructive && !confirmed {
 		return "", ErrNeedsConfirm
 	}
+	// An MCP row is a call to a configured server, not a process. Everything
+	// above still applied: it had to be enabled, and a mutating one had to be
+	// confirmed. Only the dispatch differs.
+	if server, remote, ok := mcp.ParseCmd(t.Cmd); ok {
+		if e.mcp == nil {
+			return "", ErrNotEnabled
+		}
+		ctx, cancel := context.WithTimeout(ctx, e.timeout)
+		defer cancel()
+		return e.mcp.CallPositional(ctx, server, remote, args)
+	}
 	argv := append(append([]string(nil), t.Cmd...), args...)
 	if len(argv) == 0 {
 		return "", ErrNotEnabled

internal/tool/tool_test.go

@@ -85,3 +85,103 @@ func TestExec(t *testing.T) {
 		t.Fatal("proposed tool must not match (not enabled)")
 	}
 }
+
+// fakeMCP records what the executor asked it to call.
+type fakeMCP struct {
+	server, tool string
+	args         []string
+	out          string
+	err          error
+	calls        int
+}
+
+func (f *fakeMCP) CallPositional(_ context.Context, server, tool string, args []string) (string, error) {
+	f.calls++
+	f.server, f.tool, f.args = server, tool, args
+	return f.out, f.err
+}
+
+// An MCP row dispatches to the caller instead of a process, and the process
+// seam is never touched.
+func TestExecMCPRowDispatchesToMCP(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"vikunja_list_tasks": {
+			Name: "vikunja_list_tasks", Status: "enabled", Scope: "mcp:vikunja",
+			Cmd: []string{"mcp", "vikunja", "list_tasks"},
+		},
+	}}
+	m := &fakeMCP{out: "две задачи"}
+	ran := false
+	e := NewExecutor(api, time.Second).WithMCP(m)
+	e.run = func(context.Context, []string) (string, error) { ran = true; return "", nil }
+
+	out, err := e.Exec(context.Background(), "vikunja_list_tasks", []string{"мавен"}, false)
+	if err != nil {
+		t.Fatalf("exec: %v", err)
+	}
+	if out != "две задачи" {
+		t.Fatalf("out = %q", out)
+	}
+	if ran {
+		t.Fatal("an MCP row must not be executed as a process")
+	}
+	if m.server != "vikunja" || m.tool != "list_tasks" || len(m.args) != 1 || m.args[0] != "мавен" {
+		t.Fatalf("dispatched wrong: %+v", m)
+	}
+}
+
+// The allowlist rules still apply to an MCP row: destructive means a confirm
+// turn first, and nothing is called until the second turn.
+func TestExecMCPRowStillNeedsConfirm(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"vikunja_delete_task": {
+			Name: "vikunja_delete_task", Status: "enabled", Destructive: true,
+			Cmd: []string{"mcp", "vikunja", "delete_task"},
+		},
+	}}
+	m := &fakeMCP{out: "удалила"}
+	e := NewExecutor(api, time.Second).WithMCP(m)
+	if _, err := e.Exec(context.Background(), "vikunja_delete_task", nil, false); !errors.Is(err, ErrNeedsConfirm) {
+		t.Fatalf("err = %v, want ErrNeedsConfirm", err)
+	}
+	if m.calls != 0 {
+		t.Fatal("a destructive MCP tool must not reach the server before confirmation")
+	}
+	if _, err := e.Exec(context.Background(), "vikunja_delete_task", nil, true); err != nil {
+		t.Fatalf("confirmed exec: %v", err)
+	}
+	if m.calls != 1 {
+		t.Fatalf("calls = %d", m.calls)
+	}
+}
+
+// A proposed MCP row does not run, exactly like a proposed shell tool.
+func TestExecMCPRowNotEnabled(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"vikunja_list_tasks": {Name: "vikunja_list_tasks", Status: "proposed", Cmd: []string{"mcp", "vikunja", "list_tasks"}},
+	}}
+	m := &fakeMCP{}
+	e := NewExecutor(api, time.Second).WithMCP(m)
+	if _, err := e.Exec(context.Background(), "vikunja_list_tasks", nil, false); !errors.Is(err, ErrNotEnabled) {
+		t.Fatalf("err = %v", err)
+	}
+	if m.calls != 0 {
+		t.Fatal("a proposal must not call anything")
+	}
+}
+
+// With MCP unconfigured, an MCP row refuses rather than trying to exec "mcp".
+func TestExecMCPRowWithoutCallerRefuses(t *testing.T) {
+	api := fakeAPI{tools: map[string]ipc.Tool{
+		"vikunja_list_tasks": {Name: "vikunja_list_tasks", Status: "enabled", Cmd: []string{"mcp", "vikunja", "list_tasks"}},
+	}}
+	ran := false
+	e := NewExecutor(api, time.Second)
+	e.run = func(context.Context, []string) (string, error) { ran = true; return "", nil }
+	if _, err := e.Exec(context.Background(), "vikunja_list_tasks", nil, false); !errors.Is(err, ErrNotEnabled) {
+		t.Fatalf("err = %v, want ErrNotEnabled", err)
+	}
+	if ran {
+		t.Fatal(`"mcp" must never be run as a binary`)
+	}
+}