Show similar earlier incidents and let notes be marked as the fix

The incident view gets a "Seen before" section from the server's new
/similar endpoint; an older server without it just shows nothing. C adds a
note as the resolution note, alongside c for a plain note. Needs the
server release that adds /similar.

Claude-Session: https://claude.ai/code/session_01MMados3BD1oSjevHxbmVqU

internal/api/client.go

@@ -276,6 +276,18 @@ func (c *Client) GetIncidentTimeline(id int64) ([]IncidentEvent, error) {
 	return events, c.do(req, &events)
 }
 
+// GetSimilarIncidents lists earlier resolved incidents that look like this one
+// and have notes. Servers before the similar-incidents endpoint answer 404; the
+// caller treats any error as "nothing to show".
+func (c *Client) GetSimilarIncidents(id int64) ([]SimilarIncident, error) {
+	req, err := c.newRequest(http.MethodGet, fmt.Sprintf("/api/incidents/%d/similar", id))
+	if err != nil {
+		return nil, err
+	}
+	var similar []SimilarIncident
+	return similar, c.do(req, &similar)
+}
+
 func (c *Client) AcknowledgeIncident(id int64) (*Incident, error) {
 	req, err := c.newRequest(http.MethodPost, fmt.Sprintf("/api/incidents/%d/acknowledge", id))
 	if err != nil {
@@ -357,10 +369,11 @@ func (c *Client) UnarchiveIncident(id int64) error {
 	return c.do(req, nil)
 }
 
-// AddNote appends a note to the incident's timeline.
+// AddNote appends a note to the incident's timeline. pinned files it as the
-func (c *Client) AddNote(incidentID int64, content string) (*IncidentEvent, error) {
+// resolution note: what fixed the incident, shown on similar ones later.
+func (c *Client) AddNote(incidentID int64, content string, pinned bool) (*IncidentEvent, error) {
 	req, err := c.newRequestWithBody(http.MethodPost,
-		fmt.Sprintf("/api/incidents/%d/notes", incidentID), map[string]string{"content": content})
+		fmt.Sprintf("/api/incidents/%d/notes", incidentID), map[string]any{"content": content, "pinned": pinned})
 	if err != nil {
 		return nil, err
 	}

internal/api/client_test.go

@@ -165,8 +165,10 @@ func TestClient_IncidentEndpoints(t *testing.T) {
 			http.MethodPost, "/api/incidents/7/archive", ""},
 		{"unarchive", func(c *Client) error { return c.UnarchiveIncident(7) },
 			http.MethodDelete, "/api/incidents/7/archive", ""},
-		{"add note", func(c *Client) error { _, err := c.AddNote(7, "hi"); return err },
+		{"add note", func(c *Client) error { _, err := c.AddNote(7, "hi", false); return err },
 			http.MethodPost, "/api/incidents/7/notes", ""},
+		{"similar", func(c *Client) error { _, err := c.GetSimilarIncidents(7); return err },
+			http.MethodGet, "/api/incidents/7/similar", `[]`},
 		{"delete note", func(c *Client) error { return c.DeleteNote(7, 12) },
 			http.MethodDelete, "/api/incidents/7/notes/12", ""},
 		{"stats", func(c *Client) error { _, err := c.GetIncidentStats(); return err },

internal/api/types.go

@@ -108,6 +108,10 @@ const (
 	EventResolved       = "resolved"
 	EventNote           = "note"
 
+	// A note marked as what fixed the incident. The server leads similar
+	// incidents with these.
+	EventResolutionNote = "resolution_note"
+
 	// Written when a team's dead man's switch stops reporting.
 	EventDeadmanSilent = "deadman_silent"
 
@@ -249,3 +253,15 @@ type APIKey struct {
 	CreatedAt  time.Time  `json:"created_at"`
 	LastUsedAt *time.Time `json:"last_used_at"`
 }
+
+// SimilarIncident is an earlier, resolved incident with the same signature
+// (alert name plus stable group labels) as the one being viewed. ResolutionNotes
+// are its "what fixed it" notes; NoteCount counts its plain notes.
+type SimilarIncident struct {
+	ID              int64           `json:"id"`
+	Title           string          `json:"title"`
+	TriggeredAt     time.Time       `json:"triggered_at"`
+	ResolvedAt      time.Time       `json:"resolved_at"`
+	NoteCount       int             `json:"note_count"`
+	ResolutionNotes []IncidentEvent `json:"resolution_notes"`
+}

internal/tui/model.go

@@ -146,6 +146,7 @@ type clearStatusMsg struct{}
 type incidentDetailFetchedMsg struct {
 	incident api.Incident
 	timeline []api.IncidentEvent
+	similar  []api.SimilarIncident
 }
 type alertDetailFetchedMsg struct{ alert api.Alert }
 type detailErrMsg struct{ err error }
@@ -253,7 +254,9 @@ type Model struct {
 	// Incident detail
 	selectedIncident api.Incident
 	timeline         []api.IncidentEvent
+	similar          []api.SimilarIncident
 	noteCursor       int
+	notePinned       bool // the note being typed is the resolution note
 	detailLoading    bool
 	detailViewport   viewport.Model
 
@@ -614,7 +617,7 @@ func (m *Model) refreshDetailContent() {
 		return
 	}
 	m.detailViewport.SetContent(
-		buildIncidentDetailContent(m.styles, m.selectedIncident, m.timeline, m.noteCursor, m.width))
+		buildIncidentDetailContent(m.styles, m.selectedIncident, m.timeline, m.similar, m.noteCursor, m.width))
 }
 
 func (m *Model) refreshStatsContent() {
@@ -746,7 +749,7 @@ func userFlags(u api.User) string {
 func noteEvents(timeline []api.IncidentEvent) []api.IncidentEvent {
 	notes := make([]api.IncidentEvent, 0, len(timeline))
 	for _, e := range timeline {
-		if e.Type == api.EventNote {
+		if e.Type == api.EventNote || e.Type == api.EventResolutionNote {
 			notes = append(notes, e)
 		}
 	}
@@ -1131,7 +1134,10 @@ func incidentDetail(client *api.Client, id int64) tea.Msg {
 	if err != nil {
 		return detailErrMsg{err}
 	}
-	return incidentDetailFetchedMsg{incident: *incident, timeline: timeline}
+	// Best effort: an older server has no such endpoint, and the incident is
+	// still worth showing without it.
+	similar, _ := client.GetSimilarIncidents(id)
+	return incidentDetailFetchedMsg{incident: *incident, timeline: timeline, similar: similar}
 }
 
 func fetchIncidentDetailCmd(client *api.Client, id int64) tea.Cmd {
@@ -1185,9 +1191,9 @@ func unsnoozeIncidentCmd(client *api.Client, id int64) tea.Cmd {
 	return incidentActionCmd(client, id, func() error { return client.UnsnoozeIncident(id) })
 }
 
-func addNoteCmd(client *api.Client, id int64, content string) tea.Cmd {
+func addNoteCmd(client *api.Client, id int64, content string, pinned bool) tea.Cmd {
 	return incidentActionCmd(client, id, func() error {
-		_, err := client.AddNote(id, content)
+		_, err := client.AddNote(id, content, pinned)
 		return err
 	})
 }

internal/tui/update.go

@@ -145,6 +145,7 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case incidentDetailFetchedMsg:
 		m.selectedIncident = msg.incident
 		m.timeline = msg.timeline
+		m.similar = msg.similar
 		m.detailLoading = false
 		if m.noteCursor >= len(noteEvents(m.timeline)) {
 			m.noteCursor = -1
@@ -938,8 +939,9 @@ func (m Model) handleIncidentDetailKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 		m.mode = modeDashboard
 		return m, archiveIncidentCmd(m.client, inc.ID, m.activeTeamID, m.incidentFilter)
 
-	case "c":
+	case "c", "C":
 		m.mode = modeNote
+		m.notePinned = msg.String() == "C"
 		m.noteInput.Reset()
 		m.noteInput.Focus()
 		m.detailViewport.Height = m.detailViewportHeight()
@@ -1032,7 +1034,7 @@ func (m Model) handleNoteKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 		m.mode = modeIncidentDetail
 		m.noteInput.Blur()
 		m.detailViewport.Height = m.detailViewportHeight()
-		return m, addNoteCmd(m.client, m.selectedIncident.ID, content)
+		return m, addNoteCmd(m.client, m.selectedIncident.ID, content, m.notePinned)
 	}
 
 	return m, nil

internal/tui/view.go

@@ -90,7 +90,11 @@ func (m Model) renderBody() string {
 	case modeIncidentDetail, modeAlertDetail:
 		return m.renderDetail()
 	case modeNote:
-		return m.renderPrompt(m.styles.Header.Render("Note: ") + m.noteInput.View())
+		label := "Note: "
+		if m.notePinned {
+			label = "What fixed it: "
+		}
+		return m.renderPrompt(m.styles.Header.Render(label) + m.noteInput.View())
 	case modeSnooze:
 		return m.renderPrompt(m.styles.Header.Render("Snooze for: ") + m.snoozeInput.View())
 	case modeConfirm:
@@ -135,7 +139,7 @@ func (m Model) renderFooter() string {
 	switch m.mode {
 	case modeIncidentDetail:
 		if !m.selectedIncident.IsOpen() {
-			return withStatus("  x·archive  c·note  [/]·select  d·del  esc·back")
+			return withStatus("  x·archive  c·note  C·fix note  [/]·select  d·del  esc·back")
 		}
 		return withStatus("  a·ack  A·unack  R·resolve  s·assign  z·snooze  Z·unsnooze  c·note  [/]·select  d·del  esc·back")
 
@@ -485,7 +489,7 @@ func line(style lipgloss.Style, s string) string {
 
 // ── Content builders ───────────────────────────────────────────────────────
 
-func buildIncidentDetailContent(s Styles, inc api.Incident, timeline []api.IncidentEvent, cursor, width int) string {
+func buildIncidentDetailContent(s Styles, inc api.Incident, timeline []api.IncidentEvent, similar []api.SimilarIncident, cursor, width int) string {
 	now := time.Now()
 	var b strings.Builder
 	contentW := width - 4
@@ -579,6 +583,22 @@ func buildIncidentDetailContent(s Styles, inc api.Incident, timeline []api.Incid
 	}
 	b.WriteString("\n")
 
+	// Seen before: earlier incidents of the same kind that someone left notes on.
+	if len(similar) > 0 {
+		b.WriteString(divider(s, "Seen before", width))
+		for _, sim := range similar {
+			b.WriteString(fmt.Sprintf("  #%-6d %-44s %s\n", sim.ID, truncate(sim.Title, 44),
+				s.Muted.Render("resolved "+humanAgo(now, sim.ResolvedAt))))
+			for _, n := range sim.ResolutionNotes {
+				b.WriteString("    " + s.Resolved.Render("fixed: ") + n.Detail + "\n")
+			}
+			if len(sim.ResolutionNotes) == 0 {
+				b.WriteString(line(s.Muted, fmt.Sprintf("    %d note(s), no resolution note", sim.NoteCount)))
+			}
+		}
+		b.WriteString("\n")
+	}
+
 	// Timeline — the only history the server keeps.
 	notes := noteEvents(timeline)
 	b.WriteString(divider(s, fmt.Sprintf("Timeline (%d events, %d notes)", len(timeline), len(notes)), width))
@@ -588,7 +608,7 @@ func buildIncidentDetailContent(s Styles, inc api.Incident, timeline []api.Incid
 		noteIndex := 0
 		for _, e := range timeline {
 			when := s.Muted.Render(humanAgo(now, e.CreatedAt))
-			if e.Type != api.EventNote {
+			if e.Type != api.EventNote && e.Type != api.EventResolutionNote {
 				b.WriteString(fmt.Sprintf("  %-52s %s\n", eventLabel(e), when))
 				continue
 			}
@@ -598,7 +618,11 @@ func buildIncidentDetailContent(s Styles, inc api.Incident, timeline []api.Incid
 				marker = s.Selected.Render("> ")
 				author = s.Selected.Render(e.Username)
 			}
-			b.WriteString(fmt.Sprintf("%s%-50s %s\n", marker, author+" wrote", when))
+			verb := " wrote"
+			if e.Type == api.EventResolutionNote {
+				verb = " noted the fix"
+			}
+			b.WriteString(fmt.Sprintf("%s%-50s %s\n", marker, author+verb, when))
 			b.WriteString("    " + e.Detail + "\n")
 			noteIndex++
 		}

internal/tui/view_test.go

@@ -57,7 +57,7 @@ func TestIncidentDetail_RendersTheWholeStory(t *testing.T) {
 		{Type: api.EventNote, Username: "admin", Detail: "draining node-2", CreatedAt: now},
 	}
 
-	out := buildIncidentDetailContent(testStyles(), inc, timeline, -1, 110)
+	out := buildIncidentDetailContent(testStyles(), inc, timeline, nil, -1, 110)
 	mustContain(t, out,
 		"DiskFull (namespace=prod)", "ACKNOWLEDGED", "CRITICAL",
 		"Assigned:", "admin",
@@ -77,7 +77,7 @@ func TestIncidentDetail_ShowsSnooze(t *testing.T) {
 	}
 	// The exact remaining time is humanUntil's business, not this test's — a few
 	// microseconds of elapsed clock turn "in 2h" into "in 1h 59m".
-	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, -1, 110),
+	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110),
 		"TRIGGERED (snoozed)", "Snoozed:", "until", "in 1h")
 }
 
@@ -88,7 +88,7 @@ func TestIncidentDetail_HidesExpiredSnooze(t *testing.T) {
 		Title: "Noisy", Status: api.StatusTriggered,
 		TriggeredAt: time.Now(), SnoozedUntil: &past,
 	}
-	if strings.Contains(plain(buildIncidentDetailContent(testStyles(), inc, nil, -1, 110)), "Snoozed:") {
+	if strings.Contains(plain(buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110)), "Snoozed:") {
 		t.Error("an expired snooze should not be rendered")
 	}
 }
@@ -100,18 +100,18 @@ func TestIncidentDetail_ShowsResolutionSource(t *testing.T) {
 		Title: "Done", Status: api.StatusResolved, TriggeredAt: now.Add(-time.Hour),
 		ResolvedAt: &now, ResolutionSource: &source,
 	}
-	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, -1, 110),
+	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110),
 		"RESOLVED", "Resolved:", "manual")
 }
 
 func TestIncidentDetail_UnassignedAndUnacknowledged(t *testing.T) {
 	inc := api.Incident{Title: "Fresh", Status: api.StatusTriggered, TriggeredAt: time.Now()}
-	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, -1, 110), "nobody", "not acknowledged")
+	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110), "nobody", "not acknowledged")
 }
 
 func TestIncidentDetail_EmptyTimeline(t *testing.T) {
 	inc := api.Incident{Title: "Fresh", Status: api.StatusTriggered, TriggeredAt: time.Now()}
-	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, -1, 110), "Nothing recorded yet")
+	mustContain(t, buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110), "Nothing recorded yet")
 }
 
 func TestIncidentDetail_MarksSelectedNote(t *testing.T) {
@@ -122,7 +122,7 @@ func TestIncidentDetail_MarksSelectedNote(t *testing.T) {
 	}
 	inc := api.Incident{Title: "X", Status: api.StatusTriggered, TriggeredAt: now}
 
-	out := plain(buildIncidentDetailContent(testStyles(), inc, timeline, 1, 110))
+	out := plain(buildIncidentDetailContent(testStyles(), inc, timeline, nil, 1, 110))
 	for _, line := range strings.Split(out, "\n") {
 		if strings.Contains(line, "alice") && !strings.HasPrefix(line, "> ") {
 			t.Errorf("expected the selected note marked, got %q", line)
@@ -212,7 +212,7 @@ func TestIncidentDetail_RendersNotifications(t *testing.T) {
 			Detail: "reminder: ntfy returned 502", CreatedAt: now},
 	}
 
-	got := buildIncidentDetailContent(testStyles(), inc, timeline, -1, 120)
+	got := buildIncidentDetailContent(testStyles(), inc, timeline, nil, -1, 120)
 	mustContain(t, got, "Notified niklas (triggered)", "Notification to niklas failed")
 }
 
@@ -349,3 +349,20 @@ func TestView_ZeroWidthRendersNothing(t *testing.T) {
 type errFixture struct{}
 
 func (errFixture) Error() string { return "connection refused" }
+
+func TestIncidentDetail_ShowsSimilarWithResolutionNotes(t *testing.T) {
+	now := time.Now()
+	inc := api.Incident{Title: "DiskFull", Status: api.StatusTriggered, TriggeredAt: now}
+	similar := []api.SimilarIncident{
+		{ID: 4, Title: "DiskFull (job=node)", ResolvedAt: now.Add(-48 * time.Hour),
+			ResolutionNotes: []api.IncidentEvent{{Type: api.EventResolutionNote, Detail: "rotated the logs"}}},
+		{ID: 2, Title: "DiskFull (job=node)", ResolvedAt: now.Add(-96 * time.Hour), NoteCount: 3},
+	}
+	out := plain(buildIncidentDetailContent(testStyles(), inc, nil, similar, -1, 110))
+	mustContain(t, out, "Seen before", "#4", "fixed: rotated the logs", "3 note(s), no resolution note")
+
+	// Nothing similar, no section.
+	if strings.Contains(plain(buildIncidentDetailContent(testStyles(), inc, nil, nil, -1, 110)), "Seen before") {
+		t.Error("expected no Seen before section without similar incidents")
+	}
+}