fix(board): reliability fixes for SSE lifecycle, watchdog, transport, and rendering

pkg/board/client.go

@@ -87,6 +87,7 @@ type client struct {
 // unix socket and targets the given session id.
 func newClient(socket, session string) *client {
 	transport := &http.Transport{
+		DisableKeepAlives: true,
 		DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
 			var d net.Dialer
 			return d.DialContext(ctx, "unix", socket)
@@ -149,8 +150,7 @@ func (c *client) Followup(ctx context.Context, idempotencyKey, message string) e
 	if resp.StatusCode != http.StatusAccepted {
 		return fmt.Errorf("followup: %s", resp.Status)
 	}
-	// Drain so the connection can be reused; the body only reports whether
-	// the delivery was a duplicate, which the board does not care about.
+	// Drain the small response body before closing it.
 	_, _ = io.Copy(io.Discard, resp.Body)
 	return nil
 }
@@ -201,6 +201,7 @@ func (c *client) StreamEvents(ctx context.Context, since uint64, onEvent func(ev
 	var seq uint64
 	for scanner.Scan() {
 		line := scanner.Text()
+		resetWatchdog()
 		if strings.HasPrefix(line, ":") {
 			// Heartbeat comment: the server sends them, so silence now means
 			// a hung transport. Arm the watchdog on the first one.
@@ -212,7 +213,6 @@ func (c *client) StreamEvents(ctx context.Context, since uint64, onEvent func(ev
 			}
 			continue
 		}
-		resetWatchdog()
 		if id, ok := strings.CutPrefix(line, "id:"); ok {
 			seq, _ = strconv.ParseUint(strings.TrimSpace(id), 10, 64)
 			continue

pkg/board/client_test.go

@@ -60,6 +60,31 @@ func TestStreamEventsIdleWatchdogAbortsSilentStream(t *testing.T) {
 	assert.Equal(t, eventStreamStarted, got[0].Type)
 }
 
+func TestStreamEventsHeartbeatLinesResetWatchdog(t *testing.T) {
+	old := streamIdleTimeout
+	streamIdleTimeout = 250 * time.Millisecond
+	t.Cleanup(func() { streamIdleTimeout = old })
+
+	socket := serveUnix(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		f := w.(http.Flusher)
+		for range 6 {
+			fmt.Fprint(w, ": ping\n")
+			f.Flush()
+			time.Sleep(50 * time.Millisecond) //nolint:forbidigo // heartbeat cadence is under test
+		}
+		fmt.Fprint(w, "data: {\"type\":\"stream_stopped\"}\n\n")
+		f.Flush()
+		<-r.Context().Done()
+	}))
+
+	c := newClient(socket, "sess-1")
+	err := c.StreamEvents(t.Context(), 0, func(ev event) bool {
+		assert.Equal(t, eventStreamStopped, ev.Type)
+		return false
+	})
+	require.NoError(t, err)
+}
+
 // Without any heartbeat from the server (an older docker-agent), the watchdog
 // stays unarmed: a quiet stream is left alone and events keep flowing.
 func TestStreamEventsNoHeartbeatNoWatchdog(t *testing.T) {

pkg/board/tui/tui_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	tea "charm.land/bubbletea/v2"
+	"charm.land/lipgloss/v2"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -480,6 +481,10 @@ func TestSplitTitle(t *testing.T) {
 	l1, l2 = splitTitle("A somewhat longer card title", 10)
 	assert.Equal(t, "A somewhat", l1)
 	assert.NotEmpty(t, l2)
+
+	l1, l2 = splitTitle(strings.Repeat("x", 30)+" tail", 10)
+	assert.LessOrEqual(t, lipgloss.Width(l1), 10)
+	assert.LessOrEqual(t, lipgloss.Width(l2), 10)
 }
 
 func TestColorizeDiffKeepsLineCount(t *testing.T) {

pkg/board/tui/view.go

@@ -464,7 +464,7 @@ func splitTitle(title string, width int) (string, string) {
 			candidate = line1 + " " + word
 		}
 		if line1 != "" && lipgloss.Width(candidate) > width {
-			return line1, toolcommon.TruncateText(strings.Join(words[i:], " "), width)
+			return toolcommon.TruncateText(line1, width), toolcommon.TruncateText(strings.Join(words[i:], " "), width)
 		}
 		line1 = candidate
 	}

pkg/server/server.go

@@ -624,8 +624,13 @@ func (s *Server) sessionEvents(c echo.Context) error {
 	var writeMu sync.Mutex
 
 	heartbeatCtx, stopHeartbeat := context.WithCancel(c.Request().Context())
-	defer stopHeartbeat()
+	heartbeatDone := make(chan struct{})
+	defer func() {
+		stopHeartbeat()
+		<-heartbeatDone
+	}()
 	go func() {
+		defer close(heartbeatDone)
 		ticker := time.NewTicker(s.heartbeatInterval)
 		defer ticker.Stop()
 		for {

pkg/tools/mcp/session_client.go

@@ -343,8 +343,8 @@ func (c *sessionClient) handleSamplingWithToolsRequest(ctx context.Context, req
 // requests carrying a tools array from the MCP server.
 func (c *sessionClient) SetSamplingWithToolsHandler(handler tools.SamplingWithToolsHandler) {
 	c.mu.Lock()
+	defer c.mu.Unlock()
 	c.samplingWithToolsHandler = handler
-	c.mu.Unlock()
 }
 
 // applySamplingHandlerOpts wires the SDK CreateMessage* callback into opts.