@@ -0,0 +1,206 @@
+package analytics
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+)
+
+// InsightsFacet represents an extracted insight category.
+type InsightsFacet struct {
+	Category string   `json:"category"` // goals, outcomes, friction, success
+	Items    []string `json:"items"`
+}
+
+// InsightsReport holds a complete cross-session analysis.
+type InsightsReport struct {
+	GeneratedAt     time.Time        `json:"generated_at"`
+	SessionsScanned int              `json:"sessions_scanned"`
+	DateRange       DateRange        `json:"date_range"`
+	Facets          []InsightsFacet  `json:"facets"`
+	TopPatterns     []string         `json:"top_patterns"`
+	Recommendations []string         `json:"recommendations"`
+	Stats           *SessionStats    `json:"stats,omitempty"`
+}
+
+// GenerateInsights analyzes session transcripts to extract patterns and recommendations.
+func GenerateInsights(days int, analysisFn func(content string) ([]InsightsFacet, error)) (*InsightsReport, error) {
+	sessDir := sessionsDir()
+	entries, err := os.ReadDir(sessDir)
+	if err != nil {
+		return nil, fmt.Errorf("reading sessions: %w", err)
+	}
+
+	cutoff := time.Now().AddDate(0, 0, -days)
+	var transcripts []string
+	scanned := 0
+
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil || info.ModTime().Before(cutoff) {
+			continue
+		}
+		if filepath.Ext(e.Name()) != ".jsonl" {
+			continue
+		}
+
+		data, err := os.ReadFile(filepath.Join(sessDir, e.Name()))
+		if err != nil {
+			continue
+		}
+		transcripts = append(transcripts, string(data))
+		scanned++
+	}
+
+	if scanned == 0 {
+		return nil, fmt.Errorf("no sessions found in the last %d days", days)
+	}
+
+	// Extract facets via LLM analysis if provided
+	var facets []InsightsFacet
+	if analysisFn != nil {
+		combined := strings.Join(transcripts, "\n---SESSION BREAK---\n")
+		if len(combined) > 50000 {
+			combined = combined[:50000]
+		}
+		facets, err = analysisFn(combined)
+		if err != nil {
+			// Non-fatal: continue with stats-only report
+			facets = nil
+		}
+	}
+
+	// Compute patterns from tool usage
+	patterns := extractPatterns(transcripts)
+
+	report := &InsightsReport{
+		GeneratedAt:     time.Now(),
+		SessionsScanned: scanned,
+		DateRange:       DateRange{Start: cutoff, End: time.Now()},
+		Facets:          facets,
+		TopPatterns:     patterns,
+		Recommendations: generateRecommendations(patterns, scanned),
+	}
+
+	return report, nil
+}
+
+// ExportInsightsHTML generates an HTML report from insights.
+func ExportInsightsHTML(report *InsightsReport) string {
+	var b strings.Builder
+	b.WriteString(`<!DOCTYPE html><html><head><title>Hawk Insights</title>
+<style>
+body { font-family: -apple-system, sans-serif; max-width: 800px; margin: 0 auto; padding: 20px; }
+h1 { color: #333; } h2 { color: #555; border-bottom: 1px solid #eee; }
+.stat { display: inline-block; margin: 10px; padding: 15px; background: #f5f5f5; border-radius: 8px; }
+.pattern { padding: 8px; margin: 4px 0; background: #e8f4fd; border-radius: 4px; }
+.rec { padding: 8px; margin: 4px 0; background: #e8fde8; border-radius: 4px; }
+</style></head><body>`)
+
+	b.WriteString(fmt.Sprintf("<h1>Hawk Insights Report</h1><p>Generated: %s | Sessions: %d</p>",
+		report.GeneratedAt.Format("2006-01-02 15:04"), report.SessionsScanned))
+
+	if len(report.TopPatterns) > 0 {
+		b.WriteString("<h2>Top Patterns</h2>")
+		for _, p := range report.TopPatterns {
+			b.WriteString(fmt.Sprintf(`<div class="pattern">%s</div>`, p))
+		}
+	}
+
+	if len(report.Facets) > 0 {
+		for _, f := range report.Facets {
+			b.WriteString(fmt.Sprintf("<h2>%s</h2><ul>", f.Category))
+			for _, item := range f.Items {
+				b.WriteString(fmt.Sprintf("<li>%s</li>", item))
+			}
+			b.WriteString("</ul>")
+		}
+	}
+
+	if len(report.Recommendations) > 0 {
+		b.WriteString("<h2>Recommendations</h2>")
+		for _, r := range report.Recommendations {
+			b.WriteString(fmt.Sprintf(`<div class="rec">%s</div>`, r))
+		}
+	}
+
+	b.WriteString("</body></html>")
+	return b.String()
+}
+
+// SaveInsightsReport saves an HTML report to disk.
+func SaveInsightsReport(report *InsightsReport) (string, error) {
+	home, _ := os.UserHomeDir()
+	dir := filepath.Join(home, ".hawk", "insights")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return "", err
+	}
+
+	filename := fmt.Sprintf("insights_%s.html", report.GeneratedAt.Format("2006-01-02"))
+	path := filepath.Join(dir, filename)
+
+	html := ExportInsightsHTML(report)
+	return path, os.WriteFile(path, []byte(html), 0o644)
+}
+
+func extractPatterns(transcripts []string) []string {
+	toolFreq := make(map[string]int)
+	for _, t := range transcripts {
+		for _, line := range strings.Split(t, "\n") {
+			var event map[string]interface{}
+			if json.Unmarshal([]byte(line), &event) != nil {
+				continue
+			}
+			if tool, ok := event["tool"].(string); ok {
+				toolFreq[tool]++
+			}
+		}
+	}
+
+	type kv struct {
+		k string
+		v int
+	}
+	var sorted []kv
+	for k, v := range toolFreq {
+		sorted = append(sorted, kv{k, v})
+	}
+	sort.Slice(sorted, func(i, j int) bool { return sorted[i].v > sorted[j].v })
+
+	var patterns []string
+	for i, item := range sorted {
+		if i >= 5 {
+			break
+		}
+		patterns = append(patterns, fmt.Sprintf("Heavy %s usage (%d calls)", item.k, item.v))
+	}
+	return patterns
+}
+
+func generateRecommendations(patterns []string, sessionCount int) []string {
+	var recs []string
+	if sessionCount > 20 {
+		recs = append(recs, "Consider using /compact more frequently to keep context fresh")
+	}
+	for _, p := range patterns {
+		if strings.Contains(p, "Read") {
+			recs = append(recs, "High file read count suggests exploring unfamiliar code — consider using /init to generate documentation")
+		}
+		if strings.Contains(p, "Bash") {
+			recs = append(recs, "Frequent shell usage — consider adding common commands to allowed permissions to reduce prompts")
+		}
+	}
+	return recs
+}
+
+func sessionsDir() string {
+	home, _ := os.UserHomeDir()
+	return filepath.Join(home, ".hawk", "sessions")
+}