/trace grows a turn-decisions table under the rule trace (V-564)

Both tables answer the same question, who won and who lost, one about nudges
and the other about utterances, so they share a page rather than splitting the
nav. A turn is one collapsible row; never_asked is coloured like a block,
because it usually is one. A read failure is logged and the rule trace above it
still renders: a daemon too old to know the method is the ordinary case during
a rolling deploy.

cmd/mavweb/handlers_test.go

@@ -65,6 +65,7 @@ type fakeCore struct {
 	// for handleTrace tests
 	tickTrace ipc.TickTrace
 	traceErr  error
+	turns     []ipc.TurnDecision
 
 	// for handleChatAPI tests
 	chatText   string
@@ -173,6 +174,10 @@ func (f *fakeCore) RevertFact(_ context.Context, key string) (int64, error) {
 	return f.revertNewID, nil
 }
 
+func (f *fakeCore) TurnDecisions(_ context.Context, _ int) ([]ipc.TurnDecision, error) {
+	return f.turns, nil
+}
+
 func (f *fakeCore) TickTrace(_ context.Context) (ipc.TickTrace, error) {
 	if f.traceErr != nil {
 		return ipc.TickTrace{}, f.traceErr
@@ -825,6 +830,41 @@ func TestHandleTrace(t *testing.T) {
 			t.Error("rendered 'nothing fired' but a winner was set")
 		}
 	})
+
+	// The turn arbitration shares this page (V-564). A reader must see the
+	// winner, a loser and the claimants that were never asked, because the last
+	// of those is what the hardcoded ordering hides.
+	t.Run("renders the turn decision record", func(t *testing.T) {
+		core := &fakeCore{turns: []ipc.TurnDecision{{
+			Ts:        time.Date(2025, 6, 1, 12, 0, 0, 0, time.UTC),
+			Utterance: "какая погода в риме",
+			Winner:    "query:weather",
+			Claims: []ipc.TurnClaim{
+				{Stage: "query", Claimant: "weather", Intent: "query", Outcome: "won"},
+				{Stage: "query", Claimant: "calendar", Outcome: "declined", Reason: "no answer"},
+				{Stage: "query", Claimant: "kiwix", Outcome: "never_asked"},
+			},
+		}}}
+		rr := httptest.NewRecorder()
+		handleTrace(rr, httptest.NewRequest(http.MethodGet, "/trace", nil), core)
+		body := rr.Body.String()
+		for _, want := range []string{"какая погода в риме", "query:weather", "calendar", "kiwix", "never_asked"} {
+			if !strings.Contains(body, want) {
+				t.Errorf("rendered page is missing %q", want)
+			}
+		}
+	})
+
+	t.Run("no turns renders the empty note, not an error", func(t *testing.T) {
+		rr := httptest.NewRecorder()
+		handleTrace(rr, httptest.NewRequest(http.MethodGet, "/trace", nil), &fakeCore{})
+		if rr.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rr.Code)
+		}
+		if !strings.Contains(rr.Body.String(), "no turn has run") {
+			t.Error("empty ring did not render its note")
+		}
+	})
 }
 
 // --- handleRevert ---

cmd/mavweb/main.go

@@ -1415,12 +1415,29 @@ func handleTrace(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
 		http.Error(w, "core read failed", http.StatusBadGateway)
 		return
 	}
+	// The turn records share this page rather than getting one of their own
+	// (V-564): both answer the same question — who won, who lost and why — and
+	// one is about nudges while the other is about utterances. A read failure
+	// here is not fatal to the page: the rule trace above it still renders, and
+	// a daemon too old to know the method is the ordinary case during a rolling
+	// deploy.
+	turns, err := core.TurnDecisions(ctx, 25)
+	if err != nil {
+		log.Printf("trace: turn decisions: %v", err)
+	}
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	if err := traceTmpl.Execute(w, trace); err != nil {
+	if err := traceTmpl.Execute(w, traceData{Tick: trace, Turns: turns}); err != nil {
 		log.Printf("trace render: %v", err)
 	}
 }
 
+// traceData — what trace.html renders: the last tick's rule arbitration and the
+// last turns' claim arbitration.
+type traceData struct {
+	Tick  ipc.TickTrace
+	Turns []ipc.TurnDecision
+}
+
 func handleMorning(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
 	if core == nil {
 		http.Error(w, "morning disabled (no -core)", http.StatusServiceUnavailable)

cmd/mavweb/trace.html

@@ -1,9 +1,9 @@
 {{template "shellTop" "trace"}}
 <h1>Rule Trace</h1>
-<div class="hint mb-4">{{.Now | ago}} — winner: <strong>{{if .Winner}}{{.Winner}}{{else}}nothing fired{{end}}</strong></div>
+<div class="hint mb-4">{{.Tick.Now | ago}} — winner: <strong>{{if .Tick.Winner}}{{.Tick.Winner}}{{else}}nothing fired{{end}}</strong></div>
 <div class=scroll><table class=mono>
 <tr><th>rule<th>sev<th>predicate<th>gate<th>blocked by<th>detail<th>selected<th>lost to</tr>
-{{range .Rules}}<tr>
+{{range .Tick.Rules}}<tr>
 <td>{{.RuleName}}</td>
 <td>{{.Severity}}</td>
 <td class={{if .PredicateResult}}green{{else}}gray{{end}}>{{.PredicateResult}}</td>
@@ -21,5 +21,25 @@
 <td>{{.LostTo}}</td>
 </tr>{{end}}
 </table></div>
+
+<h1 class=mt-4>Turn Decisions</h1>
+<div class="hint mb-4">Who claimed each utterance, who lost it, and who was never asked. In memory, newest first, cleared on restart.</div>
+{{if not .Turns}}<div class=hint>no turn has run since the daemon started</div>{{end}}
+{{range .Turns}}
+<details class=mb-4>
+<summary><span class=mono>{{.Utterance}}</span> — <strong>{{if .Winner}}{{.Winner}}{{else}}nobody{{end}}</strong> <span class=hint>{{.Ts | ago}}</span></summary>
+<div class=scroll><table class=mono>
+<tr><th>stage<th>claimant<th>would have been<th>score<th>outcome<th>why</tr>
+{{range .Claims}}<tr>
+<td>{{.Stage}}</td>
+<td>{{.Claimant}}</td>
+<td>{{if .Intent}}{{.Intent}}{{else}}—{{end}}</td>
+<td>{{if .HasScore}}{{printf "%.3f" .Score}}{{else}}—{{end}}</td>
+<td class={{if eq .Outcome "won"}}green{{else if eq .Outcome "never_asked"}}red{{else}}gray{{end}}>{{.Outcome}}</td>
+<td>{{.Reason}}</td>
+</tr>{{end}}
+</table></div>
+</details>
+{{end}}
 {{template "shellBottom"}}
 </html>