Fix 7 critical bugs from sweep

- Fix data race on collector.cancel between Start/Close (add cancelMu)
- Guard TopSessions against negative n (panic on slice bounds)
- Default to sonnet pricing when model string is empty
- Fix Codex parser dedup: use two-generation set (prevents double-counting)
- Fix parseTimestamp: return time.Now() on malformed input (prevents zero-time cascade into false stall alerts)
- Fix token attribution: track tokensAssigned flag so malformed first content block doesn't shift tokens to wrong event
- Handle ExportDoneMsg in Update switch (was falling through silently)

Author: rajfirke

internal/app/model.go

@@ -87,6 +87,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.ready = true
 		return m, nil
 
+	case model.ExportDoneMsg:
+		return m, nil
+
 	case model.TickMsg:
 		data := m.collector.Snapshot()
 		m.sessions = data.Sessions

internal/metrics/session.go

@@ -109,7 +109,11 @@ func (ss *SessionStore) ProcessEvent(sessionID string, event *parser.ParsedEvent
 	}
 
 	if event.Tokens.Total() > 0 {
-		cost := ss.costCalc.Calculate(event.Tokens, s.Model)
+		model := s.Model
+		if model == "" {
+			model = "claude-sonnet-4-5"
+		}
+		cost := ss.costCalc.Calculate(event.Tokens, model)
 		s.TotalCost += cost
 		s.TotalInput += event.Tokens.InputTokens
 		s.TotalOutput += event.Tokens.OutputTokens
@@ -186,6 +190,9 @@ func (ss *SessionStore) DailyTotal() float64 {
 }
 
 func (ss *SessionStore) TopSessions(n int) []CostEntry {
+	if n <= 0 {
+		return nil
+	}
 	ss.mu.RLock()
 	defer ss.mu.RUnlock()
 

internal/parser/claude.go

@@ -97,6 +97,7 @@ func (p *ClaudeParser) parseAssistant(entry *claudeEntry) ([]*ParsedEvent, error
 	}
 
 	var events []*ParsedEvent
+	tokensAssigned := false
 	for _, raw := range entry.Message.Content {
 		var c claudeContent
 		if err := json.Unmarshal(raw, &c); err != nil {
@@ -110,10 +111,10 @@ func (p *ClaudeParser) parseAssistant(entry *claudeEntry) ([]*ParsedEvent, error
 			Timestamp: ts,
 			EntryType: "assistant",
 			Model:     entry.Message.Model,
-			Tokens:    tokens,
 		}
-		if len(events) > 0 {
-			ev.Tokens = TokenUsage{}
+		if !tokensAssigned {
+			ev.Tokens = tokens
+			tokensAssigned = true
 		}
 
 		switch c.Type {
@@ -215,7 +216,13 @@ func IsTestCommand(toolInput string) bool {
 }
 
 func parseTimestamp(s string) time.Time {
-	t, _ := time.Parse(time.RFC3339Nano, s)
+	if s == "" {
+		return time.Now()
+	}
+	t, err := time.Parse(time.RFC3339Nano, s)
+	if err != nil {
+		return time.Now()
+	}
 	return t
 }
 

internal/parser/codex.go

@@ -6,13 +6,15 @@ import (
 )
 
 type CodexParser struct {
-	seenRequests map[string]bool
-	seenCount    int
+	currentGen   map[string]bool
+	previousGen  map[string]bool
+	currentCount int
 }
 
 func NewCodexParser() *CodexParser {
 	return &CodexParser{
-		seenRequests: make(map[string]bool, 256),
+		currentGen:  make(map[string]bool, 256),
+		previousGen: make(map[string]bool),
 	}
 }
 
@@ -93,15 +95,16 @@ func (p *CodexParser) Parse(line []byte) ([]*ParsedEvent, error) {
 		}
 
 		rid := entry.ID
-		if rid != "" && p.seenRequests[rid] {
+		if rid != "" && (p.currentGen[rid] || p.previousGen[rid]) {
 			return nil, nil
 		}
 		if rid != "" {
-			p.seenRequests[rid] = true
-			p.seenCount++
-			if p.seenCount > maxSeenRequests {
-				p.seenRequests = make(map[string]bool, 256)
-				p.seenCount = 0
+			p.currentGen[rid] = true
+			p.currentCount++
+			if p.currentCount > maxSeenRequests {
+				p.previousGen = p.currentGen
+				p.currentGen = make(map[string]bool, 256)
+				p.currentCount = 0
 			}
 		}
 

internal/source/collector.go

@@ -25,7 +25,8 @@ type Collector struct {
 	mu     sync.Mutex
 	alerts []model.Alert
 
-	cancel context.CancelFunc
+	cancelMu sync.Mutex
+	cancel   context.CancelFunc
 }
 
 func NewCollector(logger *slog.Logger, cfg *config.Config) *Collector {
@@ -48,7 +49,10 @@ func NewCollector(logger *slog.Logger, cfg *config.Config) *Collector {
 }
 
 func (c *Collector) Start(ctx context.Context) {
-	ctx, c.cancel = context.WithCancel(ctx)
+	ctx, cancel := context.WithCancel(ctx)
+	c.cancelMu.Lock()
+	c.cancel = cancel
+	c.cancelMu.Unlock()
 
 	c.runDiscovery()
 	c.processAllTails()
@@ -57,8 +61,11 @@ func (c *Collector) Start(ctx context.Context) {
 }
 
 func (c *Collector) Close() {
-	if c.cancel != nil {
-		c.cancel()
+	c.cancelMu.Lock()
+	cancel := c.cancel
+	c.cancelMu.Unlock()
+	if cancel != nil {
+		cancel()
 	}
 }