Stabilize search pipeline and improve preview diagnostics

TODO.md

@@ -23,6 +23,33 @@
   - `go build ./backend` from repo root conflicts with the existing `backend/` directory name
   - verified build command is now treated as `go build -o /tmp/... ./backend`
 
+## Current Session Update (2026-03-13, Search/Preview Follow-up)
+- Investigated a production search failure using downloaded frontend logs.
+- Identified the main timeout cause:
+  - too many search results were being collected
+  - too many Gemini Vision batches were being evaluated sequentially
+  - backend debug messages were broadcasting oversized result payloads
+- Applied search pipeline optimization:
+  - reduced per-source result caps
+  - reduced query fan-out for Google Video
+  - reduced enrichment cap
+  - limited Gemini Vision evaluation to top-ranked candidates only
+- Improved Google Video filtering:
+  - added bans for music/BGM/trailer-style noise results
+- Improved Envato enrichment fidelity:
+  - source page metadata is now preferred over search-engine proxy thumbnails
+  - source snippet/title are now taken from page metadata when available
+  - preview mp4 extraction now works via HTML/JSON-LD parsing
+  - added Python HTML fetch fallback for Cloudflare-challenged Envato pages because Go HTTP alone was receiving 403 challenge pages in testing
+- Improved Artgrid fidelity:
+  - source page title/description/thumbnail are now preferred over search-engine snippets when available
+  - preview extraction is still not considered solved for all Artgrid clips because public HTML tested here did not expose a stable mp4/m3u8 URL
+- Improved logging:
+  - backend search debug events now emit summaries, timings, source counts, preview counts, and Gemini batch stats instead of giant raw arrays
+  - frontend now logs raw non-JSON error bodies instead of collapsing them to `{}` on gateway/proxy failures
+- Improved result rendering:
+  - search cards now show source snippet/description separately from AI reason to reduce confusion between asset metadata and Gemini commentary
+
 ## Local Self-Test Workflow
 - Primary command:
   - `bash scripts/selftest.sh`
@@ -145,7 +172,8 @@
 - Gemini batch evaluation exists, but search quality can still degrade if upstream SearXNG results are noisy.
 - Frontend JavaScript was not linted with Node tooling in this environment because `node` is not installed here.
 - Full browser-level preview validation is still not covered by the local self-test script.
-- Search cards still render recommendation reason text, not a robust asset description/snippet mapping.
+- Search cards now separate source snippet from AI reason, but metadata fidelity still depends on source enrichment quality.
+- Artgrid public pages inspected from this environment still did not expose a stable public preview video URL in HTML, so Artgrid hover-video support may remain partial until a browser-captured HTML/HAR sample reveals the real preview source pattern.
 
 ## Frontend Debug Logger
 - UI button: bottom-right `Logs`
@@ -215,6 +243,7 @@
 - [ ] Better matching between rendered description and actual linked asset
 - [ ] Add browser-level verification for preview/HLS behavior
 - [ ] Add more automated coverage for search ranking / filtering logic
+- [ ] If Artgrid hover preview is still required, collect one real clip HTML/HAR from a browser session and derive a stable preview URL parser
 - [ ] Add proper frontend build/lint step if Node becomes available
 
 ## Verified Locally In This Environment

backend/handlers/api.go

@@ -76,6 +76,27 @@ type PreviewResponse struct {
 	Qualities        []map[string]any `json:"qualities"`
 }
 
+type searchDebugSummary struct {
+	Total              int              `json:"total"`
+	BySource           map[string]int   `json:"bySource"`
+	WithPreview        int              `json:"withPreview"`
+	WithThumbnail      int              `json:"withThumbnail"`
+	Top                []map[string]any `json:"top"`
+	Warning            string           `json:"warning,omitempty"`
+	DurationMS         int64            `json:"durationMs,omitempty"`
+	GeminiCandidateCap int              `json:"geminiCandidateCap,omitempty"`
+}
+
+type geminiBatchStats struct {
+	CandidateCap     int      `json:"candidateCap"`
+	Requested        int      `json:"requested"`
+	Batches          int      `json:"batches"`
+	Succeeded        int      `json:"succeeded"`
+	Failed           int      `json:"failed"`
+	RecommendedCount int      `json:"recommendedCount"`
+	Errors           []string `json:"errors,omitempty"`
+}
+
 func RegisterRoutes(router *gin.Engine, app *App) {
 	router.GET("/healthz", func(c *gin.Context) {
 		c.JSON(http.StatusOK, gin.H{"status": "ok"})
@@ -259,6 +280,7 @@ func (a *App) runDownload(recordID int64, url, start, end, quality, outputPath s
 }
 
 func (a *App) searchMedia(c *gin.Context) {
+	started := time.Now()
 	var req struct {
 		Query     string   `json:"query"`
 		Platforms []string `json:"platforms"`
@@ -277,18 +299,24 @@ func (a *App) searchMedia(c *gin.Context) {
 	if len(queryVariants) == 0 {
 		queryVariants = []string{req.Query}
 	}
-	a.debug("search query variants", gin.H{"query": req.Query, "variants": queryVariants, "platforms": req.Platforms})
+	a.debug("search query variants", gin.H{
+		"query":         req.Query,
+		"platforms":     req.Platforms,
+		"variants":      queryVariants,
+		"variantCount":  len(queryVariants),
+		"requestIdHint": time.Now().UnixNano(),
+	})
 
 	enabledPlatforms := normalizePlatforms(req.Platforms)
 	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "searching " + selectedPlatformLabel(enabledPlatforms), "progress": 35})
 	results, err := a.SearchService.SearchMedia(queryVariants, enabledPlatforms)
 	if err != nil {
-		a.debug("search backend failed", gin.H{"error": err.Error(), "variants": queryVariants})
+		a.debug("search backend failed", gin.H{"error": err.Error(), "variants": queryVariants, "durationMs": time.Since(started).Milliseconds()})
 		a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "search failed", "progress": 100, "message": err.Error()})
 		c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
 		return
 	}
-	a.debug("search backend results", gin.H{"count": len(results), "results": results})
+	a.debug("search backend summary", summarizeSearchResults(results, time.Since(started), 0, ""))
 	if len(results) == 0 {
 		warning := "SearXNG returned no renderable results."
 		a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "no renderable search results", "progress": 100, "message": warning})
@@ -302,10 +330,10 @@ func (a *App) searchMedia(c *gin.Context) {
 		rankQuery = strings.Join(queryVariants[:min(len(queryVariants), 3)], " ")
 	}
 	scored := rankSearchResults(rankQuery, results)
-	a.debug("search ranked results", gin.H{"count": len(scored), "results": scored})
-	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "analyzing all candidate visuals with Gemini Vision", "progress": 75})
-	recommended := evaluateAllCandidatesWithGemini(a.GeminiService, req.Query, scored)
-	a.debug("search gemini recommendations", gin.H{"count": len(recommended), "results": recommended})
+	a.debug("search ranked summary", summarizeSearchResults(scored, time.Since(started), geminiCandidateLimit(len(scored)), ""))
+	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "analyzing top candidate visuals with Gemini Vision", "progress": 75})
+	recommended, geminiStats := evaluateAllCandidatesWithGemini(a.GeminiService, req.Query, scored)
+	a.debug("search gemini evaluation", geminiStats)
 	err = nil
 	if len(recommended) == 0 {
 		err = fmt.Errorf("gemini vision returned no recommended items across all candidate batches")
@@ -316,6 +344,7 @@ func (a *App) searchMedia(c *gin.Context) {
 			fallback = append(fallback, services.AIRecommendation{
 				Title:           result.Title,
 				Link:            result.Link,
+				Snippet:         result.Snippet,
 				ThumbnailURL:    result.ThumbnailURL,
 				PreviewVideoURL: result.PreviewVideoURL,
 				Source:          result.Source,
@@ -324,12 +353,15 @@ func (a *App) searchMedia(c *gin.Context) {
 			})
 		}
 		warning := err.Error()
+		a.debug("search fallback summary", summarizeRecommendationResults(fallback, time.Since(started), warning))
 		a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "Gemini Vision fallback to ranked results", "progress": 90, "message": warning})
 		c.JSON(http.StatusOK, gin.H{"results": fallback, "warning": warning, "queries": queryVariants})
 		return
 	}
 
-	response := gin.H{"results": mergeRecommendations(recommended, scored, 20), "queries": queryVariants}
+	merged := mergeRecommendations(recommended, scored, 20)
+	a.debug("search complete summary", summarizeRecommendationResults(merged, time.Since(started), ""))
+	response := gin.H{"results": merged, "queries": queryVariants}
 	a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "search complete", "progress": 100})
 	c.JSON(http.StatusOK, response)
 }
@@ -406,20 +438,31 @@ func selectedPlatformLabel(platforms map[string]bool) string {
 	return strings.Join(labels, ", ")
 }
 
-func evaluateAllCandidatesWithGemini(service *services.GeminiService, query string, ranked []services.SearchResult) []services.AIRecommendation {
+func evaluateAllCandidatesWithGemini(service *services.GeminiService, query string, ranked []services.SearchResult) ([]services.AIRecommendation, geminiBatchStats) {
 	const chunkSize = 8
+	limit := geminiCandidateLimit(len(ranked))
+	stats := geminiBatchStats{
+		CandidateCap: limit,
+		Requested:    min(limit, len(ranked)),
+	}
 	merged := make([]services.AIRecommendation, 0, len(ranked))
 	seen := map[string]bool{}
-	for start := 0; start < len(ranked); start += chunkSize {
+	for start := 0; start < limit; start += chunkSize {
 		end := start + chunkSize
-		if end > len(ranked) {
-			end = len(ranked)
+		if end > limit {
+			end = limit
 		}
 		batch := ranked[start:end]
+		stats.Batches++
 		recommended, err := service.Recommend(query, batch)
 		if err != nil {
+			stats.Failed++
+			if len(stats.Errors) < 5 {
+				stats.Errors = append(stats.Errors, err.Error())
+			}
 			continue
 		}
+		stats.Succeeded++
 		for _, item := range recommended {
 			if item.Link == "" || seen[item.Link] {
 				continue
@@ -428,7 +471,8 @@ func evaluateAllCandidatesWithGemini(service *services.GeminiService, query stri
 			merged = append(merged, item)
 		}
 	}
-	return merged
+	stats.RecommendedCount = len(merged)
+	return merged, stats
 }
 
 func rankSearchResults(query string, results []services.SearchResult) []services.SearchResult {
@@ -515,6 +559,7 @@ func mergeRecommendations(recommended []services.AIRecommendation, ranked []serv
 		merged = append(merged, services.AIRecommendation{
 			Title:           item.Title,
 			Link:            item.Link,
+			Snippet:         item.Snippet,
 			ThumbnailURL:    item.ThumbnailURL,
 			PreviewVideoURL: item.PreviewVideoURL,
 			Source:          item.Source,
@@ -525,6 +570,96 @@ func mergeRecommendations(recommended []services.AIRecommendation, ranked []serv
 	return merged
 }
 
+func geminiCandidateLimit(total int) int {
+	switch {
+	case total <= 8:
+		return total
+	case total <= 16:
+		return 12
+	default:
+		return 16
+	}
+}
+
+func summarizeSearchResults(results []services.SearchResult, duration time.Duration, geminiCap int, warning string) searchDebugSummary {
+	bySource := map[string]int{}
+	withPreview := 0
+	withThumbnail := 0
+	top := make([]map[string]any, 0, min(6, len(results)))
+	for idx, item := range results {
+		bySource[item.Source]++
+		if strings.TrimSpace(item.PreviewVideoURL) != "" {
+			withPreview++
+		}
+		if strings.TrimSpace(item.ThumbnailURL) != "" {
+			withThumbnail++
+		}
+		if idx < 6 {
+			top = append(top, map[string]any{
+				"title":         truncateText(item.Title, 120),
+				"source":        item.Source,
+				"hasPreview":    item.PreviewVideoURL != "",
+				"hasThumbnail":  item.ThumbnailURL != "",
+				"displayLink":   item.DisplayLink,
+				"snippetSample": truncateText(item.Snippet, 160),
+			})
+		}
+	}
+	return searchDebugSummary{
+		Total:              len(results),
+		BySource:           bySource,
+		WithPreview:        withPreview,
+		WithThumbnail:      withThumbnail,
+		Top:                top,
+		Warning:            warning,
+		DurationMS:         duration.Milliseconds(),
+		GeminiCandidateCap: geminiCap,
+	}
+}
+
+func summarizeRecommendationResults(results []services.AIRecommendation, duration time.Duration, warning string) searchDebugSummary {
+	bySource := map[string]int{}
+	withPreview := 0
+	withThumbnail := 0
+	top := make([]map[string]any, 0, min(6, len(results)))
+	for idx, item := range results {
+		bySource[item.Source]++
+		if strings.TrimSpace(item.PreviewVideoURL) != "" {
+			withPreview++
+		}
+		if strings.TrimSpace(item.ThumbnailURL) != "" {
+			withThumbnail++
+		}
+		if idx < 6 {
+			top = append(top, map[string]any{
+				"title":         truncateText(item.Title, 120),
+				"source":        item.Source,
+				"hasPreview":    item.PreviewVideoURL != "",
+				"hasThumbnail":  item.ThumbnailURL != "",
+				"reasonSample":  truncateText(item.Reason, 120),
+				"snippetSample": truncateText(item.Snippet, 160),
+			})
+		}
+	}
+	return searchDebugSummary{
+		Total:         len(results),
+		BySource:      bySource,
+		WithPreview:   withPreview,
+		WithThumbnail: withThumbnail,
+		Top:           top,
+		Warning:       warning,
+		DurationMS:    duration.Milliseconds(),
+	}
+}
+
+func truncateText(text string, limit int) string {
+	trimmed := strings.TrimSpace(text)
+	if len(trimmed) <= limit {
+		return trimmed
+	}
+	return trimmed[:limit] + "..."
+}
+
 func EnsurePaths(downloadsDir, workerScript string) error {
 	if err := os.MkdirAll(downloadsDir, 0o755); err != nil {
 		return err

backend/services/cse.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os/exec"
 	"regexp"
 	"sort"
 	"strings"
@@ -54,6 +55,7 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 		name       string
 		categories string
 		engine     string
+		maxResults int
 		build      func(string) []string
 		accept     func(SearchResult) bool
 	}
@@ -63,6 +65,7 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 			name:       "Envato",
 			categories: "general",
 			engine:     s.WebEngine,
+			maxResults: 8,
 			build:      buildEnvatoQueries,
 			accept:     isRenderableEnvatoResult,
 		},
@@ -70,6 +73,7 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 			name:       "Artgrid",
 			categories: "general",
 			engine:     s.WebEngine,
+			maxResults: 8,
 			build:      buildArtgridQueries,
 			accept:     isRenderableArtgridResult,
 		},
@@ -77,16 +81,18 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 			name:       "Google Video",
 			categories: "videos",
 			engine:     s.GoogleVideoEngine,
+			maxResults: 6,
 			build:      buildGoogleVideoQueries,
 			accept:     isUsefulGoogleVideoResult,
 		},
 	}
 
 	seen := map[string]bool{}
+	sourceCounts := map[string]int{}
 	results := make([]SearchResult, 0, 90)
 	var lastErr error
 
-	baseQueries := limitQueries(queries, 5)
+	baseQueries := limitQueries(queries, 3)
 	for _, base := range baseQueries {
 		base = strings.TrimSpace(base)
 		if base == "" {
@@ -96,7 +102,13 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 			if len(enabledPlatforms) > 0 && !enabledPlatforms[strings.ToLower(source.name)] {
 				continue
 			}
+			if sourceCounts[source.name] >= source.maxResults {
+				continue
+			}
 			for _, searchQuery := range source.build(base) {
+				if sourceCounts[source.name] >= source.maxResults {
+					break
+				}
 				items, err := s.search(searchQuery, source.categories, source.engine, source.name)
 				if err != nil {
 					lastErr = err
@@ -112,6 +124,10 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 					}
 					seen[item.Link] = true
 					results = append(results, item)
+					sourceCounts[source.name]++
+					if sourceCounts[source.name] >= source.maxResults {
+						break
+					}
 				}
 			}
 		}
@@ -128,7 +144,7 @@ func (s *SearchService) SearchMedia(queries []string, enabledPlatforms map[strin
 }
 
 func (s *SearchService) EnrichResults(results []SearchResult) []SearchResult {
-	limit := minInt(len(results), 24)
+	limit := minInt(len(results), 18)
 	if limit == 0 {
 		return results
 	}
@@ -170,14 +186,32 @@ func (s *SearchService) enrichEnvato(result SearchResult) SearchResult {
 	if err != nil {
 		return result
 	}
-	if result.ThumbnailURL == "" {
-		result.ThumbnailURL = firstNonEmpty(
-			extractMetaContent(html, "og:image"),
-			extractMetaContent(html, "twitter:image"),
-		)
+	result.Title = firstNonEmpty(
+		extractMetaContent(html, "og:title"),
+		result.Title,
+	)
+	result.Snippet = firstNonEmpty(
+		extractMetaContent(html, "og:description"),
+		extractMetaContent(html, "description"),
+		result.Snippet,
+	)
+
+	pageThumbnail := firstNonEmpty(
+		extractMetaContent(html, "og:image"),
+		extractMetaContent(html, "twitter:image"),
+		extractJSONLDValue(html, "thumbnailUrl"),
+	)
+	if shouldPreferPageThumbnail(result.ThumbnailURL, result.Link) {
+		result.ThumbnailURL = pageThumbnail
 	}
 	if result.PreviewVideoURL == "" {
-		result.PreviewVideoURL = extractVideoPreviewURL(html)
+		result.PreviewVideoURL = firstNonEmpty(
+			extractJSONLDValue(html, "contentUrl"),
+			extractMetaContent(html, "twitter:player:stream"),
+			extractVideoPreviewURL(html),
+			deriveEnvatoPreviewFromThumbnail(pageThumbnail),
+			deriveEnvatoPreviewFromThumbnail(result.ThumbnailURL),
+		)
 	}
 	return result
 }
@@ -203,17 +237,30 @@ func (s *SearchService) enrichArtgrid(result SearchResult) SearchResult {
 	if result.ThumbnailURL == "" || result.PreviewVideoURL == "" {
 		html, err := s.fetchText(result.Link)
 		if err == nil {
-			if result.ThumbnailURL == "" {
-				result.ThumbnailURL = firstNonEmpty(
-					extractMetaContent(html, "og:image"),
-					extractMetaContent(html, "twitter:image"),
-				)
-				if result.ThumbnailURL == "" {
-					result.ThumbnailURL = extractArtgridBackgroundThumbnail(html, clipID)
-				}
+			result.Title = firstNonEmpty(
+				extractMetaContent(html, "og:title"),
+				result.Title,
+			)
+			result.Snippet = firstNonEmpty(
+				extractMetaContent(html, "og:description"),
+				extractMetaContent(html, "description"),
+				result.Snippet,
+			)
+			pageThumbnail := firstNonEmpty(
+				extractMetaContent(html, "og:image"),
+				extractMetaContent(html, "twitter:image"),
+				extractArtgridBackgroundThumbnail(html, clipID),
+				extractJSONLDValue(html, "image"),
+			)
+			if shouldPreferPageThumbnail(result.ThumbnailURL, result.Link) {
+				result.ThumbnailURL = pageThumbnail
 			}
 			if result.PreviewVideoURL == "" {
-				result.PreviewVideoURL = extractVideoPreviewURL(html)
+				result.PreviewVideoURL = firstNonEmpty(
+					extractJSONLDValue(html, "contentUrl"),
+					extractMetaContent(html, "twitter:player:stream"),
+					extractVideoPreviewURL(html),
+				)
 			}
 		}
 	}
@@ -282,7 +329,6 @@ func (s *SearchService) search(query, categories, engine, source string) ([]Sear
 func buildGoogleVideoQueries(base string) []string {
 	return []string{
 		fmt.Sprintf(`"%s" ("stock footage" OR "b-roll" OR cinematic OR "establishing shot" OR editorial) -tutorial -"how to" -review -reaction -course -podcast -vlog -interview -breakdown -edit -editing`, base),
-		fmt.Sprintf(`"%s" ("cinematic footage" OR "free stock footage" OR "4k footage") -tutorial -"how to" -review`, base),
 	}
 }
 
@@ -310,6 +356,8 @@ func isUsefulGoogleVideoResult(result SearchResult) bool {
 		"tutorial", "how to", "review", "reaction", "podcast", "interview", "walkthrough",
 		"course", "lesson", "edit tutorial", "editing tutorial", "premiere pro", "after effects",
 		"breakdown", "explained", "vlog", "tips", "guide", "learn", "free download",
+		"bgm", "music", "song", "lyrics", "audio", "soundtrack", "trailer", "teaser",
+		"full movie", "movie clip", "status", "whatsapp status", "fan cam", "fancam",
 	} {
 		if strings.Contains(text, banned) {
 			return false
@@ -477,11 +525,18 @@ func pickVideoURL(urls []string) string {
 }
 
 func (s *SearchService) fetchText(target string) (string, error) {
-	resp, err := s.Client.Get(target)
+	req, err := newBrowserRequest(http.MethodGet, target, "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+	if err != nil {
+		return "", err
+	}
+	resp, err := s.Client.Do(req)
 	if err != nil {
 		return "", err
 	}
 	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusForbidden || resp.StatusCode == http.StatusServiceUnavailable {
+		return fetchTextViaPython(target)
+	}
 	if resp.StatusCode >= 300 {
 		return "", fmt.Errorf("fetch returned status %d", resp.StatusCode)
 	}
@@ -489,15 +544,17 @@ func (s *SearchService) fetchText(target string) (string, error) {
 	if err != nil {
 		return "", err
 	}
+	if looksLikeCloudflareChallenge(string(data)) {
+		return fetchTextViaPython(target)
+	}
 	return string(data), nil
 }
 
 func (s *SearchService) fetchJSONText(target string) (string, error) {
-	req, err := http.NewRequest(http.MethodGet, target, nil)
+	req, err := newBrowserRequest(http.MethodGet, target, "application/json, text/json, */*")
 	if err != nil {
 		return "", err
 	}
-	req.Header.Set("Accept", "application/json, text/json")
 	resp, err := s.Client.Do(req)
 	if err != nil {
 		return "", err
@@ -522,6 +579,106 @@ func firstNonEmpty(values ...string) string {
 	return ""
 }
 
+func shouldPreferPageThumbnail(current, pageLink string) bool {
+	current = strings.TrimSpace(current)
+	if current == "" {
+		return true
+	}
+	lower := strings.ToLower(current)
+	if strings.Contains(lower, "imgs.search.brave.com") || strings.Contains(lower, "googleusercontent.com") || strings.Contains(lower, "bing.com") {
+		return true
+	}
+	currentHost := hostOf(current)
+	pageHost := hostOf(pageLink)
+	return currentHost == "" || (pageHost != "" && currentHost != pageHost)
+}
+
+func hostOf(raw string) string {
+	parsed, err := url.Parse(raw)
+	if err != nil {
+		return ""
+	}
+	return strings.ToLower(parsed.Host)
+}
+
+func extractJSONLDValue(html, key string) string {
+	pattern := regexp.MustCompile(`"` + regexp.QuoteMeta(key) + `"\s*:\s*"(https?:\\?/\\?/[^"]+|[^"]+)"`)
+	matches := pattern.FindAllStringSubmatch(html, -1)
+	for _, match := range matches {
+		if len(match) != 2 {
+			continue
+		}
+		value := strings.ReplaceAll(match[1], `\/`, `/`)
+		value = strings.ReplaceAll(value, `\u002F`, `/`)
+		value = strings.ReplaceAll(value, `\\`, "")
+		value = htmlUnescape(value)
+		if strings.TrimSpace(value) != "" {
+			return value
+		}
+	}
+	return ""
+}
+
+func deriveEnvatoPreviewFromThumbnail(thumbnail string) string {
+	candidate := htmlUnescape(strings.TrimSpace(thumbnail))
+	if candidate == "" {
+		return ""
+	}
+	candidate = strings.ReplaceAll(candidate, "&", "&")
+	if strings.Contains(candidate, "/video_preview/") {
+		if idx := strings.Index(candidate, "?"); idx >= 0 {
+			candidate = candidate[:idx]
+		}
+		return regexp.MustCompile(`/video_preview/[^/]+\.(?:jpg|jpeg|png|webp)$`).ReplaceAllString(candidate, `/watermarked_preview/watermarked_preview.mp4`)
+	}
+	return ""
+}
+
+func newBrowserRequest(method, target, accept string) (*http.Request, error) {
+	req, err := http.NewRequest(method, target, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36")
+	req.Header.Set("Accept-Language", "en-US,en;q=0.9")
+	if accept != "" {
+		req.Header.Set("Accept", accept)
+	}
+	return req, nil
+}
+
+func fetchTextViaPython(target string) (string, error) {
+	script := `
+from urllib.request import Request, urlopen
+import sys
+req = Request(sys.argv[1], headers={
+    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36",
+    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
+    "Accept-Language": "en-US,en;q=0.9",
+})
+with urlopen(req, timeout=20) as resp:
+    sys.stdout.buffer.write(resp.read(1024 * 1024))
+`
+	output, err := exec.Command("python3", "-c", script, target).CombinedOutput()
+	if err != nil {
+		return "", fmt.Errorf("python fallback failed: %v: %s", err, truncateBytes(output, 300))
+	}
+	return string(output), nil
+}
+
+func looksLikeCloudflareChallenge(body string) bool {
+	lower := strings.ToLower(body)
+	return strings.Contains(lower, "cf-mitigated") || strings.Contains(lower, "attention required") || strings.Contains(lower, "just a moment")
+}
+
+func truncateBytes(data []byte, limit int) string {
+	trimmed := strings.TrimSpace(string(data))
+	if len(trimmed) <= limit {
+		return trimmed
+	}
+	return trimmed[:limit] + "..."
+}
+
 func limitQueries(queries []string, limit int) []string {
 	seen := map[string]bool{}
 	filtered := make([]string, 0, minInt(len(queries), limit))

backend/services/cse_test.go

@@ -0,0 +1,32 @@
+package services
+
+import "testing"
+
+func TestExtractVideoPreviewURLFindsEnvatoPreview(t *testing.T) {
+	html := `<script type="application/ld+json">{"contentUrl":"https://video-previews.elements.envatousercontent.com/ad0a3abc-7eb0-4075-8f68-8198f9a08777/watermarked_preview/watermarked_preview.mp4"}</script>`
+	got := firstNonEmpty(extractJSONLDValue(html, "contentUrl"), extractVideoPreviewURL(html))
+	want := "https://video-previews.elements.envatousercontent.com/ad0a3abc-7eb0-4075-8f68-8198f9a08777/watermarked_preview/watermarked_preview.mp4"
+	if got != want {
+		t.Fatalf("expected %q, got %q", want, got)
+	}
+}
+
+func TestDeriveEnvatoPreviewFromThumbnail(t *testing.T) {
+	thumb := "https://elements-resized.envatousercontent.com/elements-video-cover-images/ad0a3abc-7eb0-4075-8f68-8198f9a08777/video_preview/video_preview_0000.jpg?w=1200&amp;h=630"
+	got := deriveEnvatoPreviewFromThumbnail(thumb)
+	want := "https://elements-resized.envatousercontent.com/elements-video-cover-images/ad0a3abc-7eb0-4075-8f68-8198f9a08777/watermarked_preview/watermarked_preview.mp4"
+	if got != want {
+		t.Fatalf("expected %q, got %q", want, got)
+	}
+}
+
+func TestIsUsefulGoogleVideoResultRejectsMusicResults(t *testing.T) {
+	result := SearchResult{
+		Title:   "Couple Friendly Sad Bgm Movie Best Bgm",
+		Link:    "https://www.youtube.com/watch?v=LGP4wiXSw8c",
+		Snippet: "romantic bgm soundtrack",
+	}
+	if isUsefulGoogleVideoResult(result) {
+		t.Fatal("expected bgm/music result to be rejected")
+	}
+}

backend/services/gemini.go

@@ -27,6 +27,7 @@ type GeminiService struct {
 type AIRecommendation struct {
 	Title           string `json:"title"`
 	Link            string `json:"link"`
+	Snippet         string `json:"snippet"`
 	ThumbnailURL    string `json:"thumbnailUrl"`
 	PreviewVideoURL string `json:"previewVideoUrl"`
 	Source          string `json:"source"`
@@ -232,6 +233,7 @@ User query: ` + query,
 		recommendations = append(recommendations, AIRecommendation{
 			Title:           src.Title,
 			Link:            src.Link,
+			Snippet:         src.Snippet,
 			ThumbnailURL:    src.ThumbnailURL,
 			PreviewVideoURL: src.PreviewVideoURL,
 			Source:          src.Source,
@@ -245,6 +247,7 @@ User query: ` + query,
 			recommendations = append(recommendations, AIRecommendation{
 				Title:           candidate.Title,
 				Link:            candidate.Link,
+				Snippet:         candidate.Snippet,
 				ThumbnailURL:    candidate.ThumbnailURL,
 				PreviewVideoURL: candidate.PreviewVideoURL,
 				Source:          candidate.Source,
@@ -262,10 +265,26 @@ func fetchImageAsInlineData(client *http.Client, imageURL string) (string, strin
 		return "", "", fmt.Errorf("image url is empty")
 	}
 	resp, err := client.Get(imageURL)
-	if err != nil {
-		return "", "", err
+	if err == nil {
+		defer resp.Body.Close()
+	}
+	if err != nil || resp.StatusCode >= 300 {
+		req, reqErr := newBrowserStyleImageRequest(imageURL)
+		if reqErr != nil {
+			if err != nil {
+				return "", "", err
+			}
+			return "", "", reqErr
+		}
+		if resp != nil {
+			resp.Body.Close()
+		}
+		resp, err = client.Do(req)
+		if err != nil {
+			return "", "", err
+		}
+		defer resp.Body.Close()
 	}
-	defer resp.Body.Close()
 
 	if resp.StatusCode >= 300 {
 		return "", "", fmt.Errorf("thumbnail fetch failed with %d", resp.StatusCode)
@@ -284,6 +303,17 @@ func fetchImageAsInlineData(client *http.Client, imageURL string) (string, strin
 	return base64.StdEncoding.EncodeToString(data), mimeType, nil
 }
 
+func newBrowserStyleImageRequest(imageURL string) (*http.Request, error) {
+	req, err := http.NewRequest(http.MethodGet, imageURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36")
+	req.Header.Set("Accept", "image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8")
+	req.Header.Set("Accept-Language", "en-US,en;q=0.9")
+	return req, nil
+}
+
 func fetchCandidateVisualInlineData(client *http.Client, candidate SearchResult) (string, string, error) {
 	if candidate.ThumbnailURL != "" {
 		data, mimeType, err := fetchImageAsInlineData(client, candidate.ThumbnailURL)

frontend/app.js

@@ -68,12 +68,36 @@ function logEvent(type, payload) {
 
 function safeStringify(value) {
   try {
-    return JSON.stringify(value, null, 2);
+    return JSON.stringify(compactPayload(value), null, 2);
   } catch {
     return String(value);
   }
 }
 
+function compactPayload(value, depth = 0) {
+  if (depth > 3) {
+    return "[truncated]";
+  }
+  if (Array.isArray(value)) {
+    if (value.length > 8) {
+      return {
+        type: "array",
+        length: value.length,
+        sample: value.slice(0, 5).map((item) => compactPayload(item, depth + 1)),
+      };
+    }
+    return value.map((item) => compactPayload(item, depth + 1));
+  }
+  if (value && typeof value === "object") {
+    const entries = Object.entries(value);
+    return Object.fromEntries(entries.map(([key, item]) => [key, compactPayload(item, depth + 1)]));
+  }
+  if (typeof value === "string" && value.length > 500) {
+    return `${value.slice(0, 500)}...`;
+  }
+  return value;
+}
+
 function renderLogs() {
   debugSummary.textContent = `${debugEntries.length} events captured`;
   debugLogList.innerHTML = "";
@@ -194,15 +218,24 @@ async function api(path, options = {}) {
     bodyPreview: typeof options.body === "string" ? options.body.slice(0, 800) : "[non-string body]",
   });
   const response = await fetch(path, options);
-  const data = await response.json().catch(() => ({}));
+  const rawText = await response.text();
+  let data = {};
+  if (rawText) {
+    try {
+      data = JSON.parse(rawText);
+    } catch {
+      data = { rawText };
+    }
+  }
   logEvent("api:response", {
     path,
     status: response.status,
     ok: response.ok,
-    body: data,
+    body: compactPayload(data),
   });
   if (!response.ok) {
-    const error = new Error(data.error || "request failed");
+    const message = data.error || data.rawText || `request failed (${response.status})`;
+    const error = new Error(message);
     error.status = response.status;
     error.data = data;
     throw error;
@@ -263,7 +296,8 @@ function renderResults(results) {
     image.src = item.thumbnailUrl || "https://placehold.co/1280x720/0a0a0a/ffffff?text=Preview";
     image.alt = item.title;
     node.querySelector("h3").textContent = item.title;
-    node.querySelector("p").textContent = item.reason;
+    node.querySelector(".result-snippet").textContent = item.snippet || item.reason || item.source || "";
+    node.querySelector(".result-reason").textContent = item.reason ? `AI note: ${item.reason}` : "";
     node.querySelector(".source-badge").textContent = item.source;
     if (item.previewVideoUrl) {
       attachVideoSource(previewVideo, item.previewVideoUrl);

frontend/index.html

@@ -159,7 +159,8 @@
         </div>
         <div class="space-y-2 p-5">
           <h3 class="line-clamp-2 text-base font-medium text-white"></h3>
-          <p class="line-clamp-3 text-sm text-zinc-400"></p>
+          <p class="result-snippet line-clamp-3 text-sm text-zinc-400"></p>
+          <p class="result-reason line-clamp-2 text-xs uppercase tracking-[0.12em] text-zinc-500"></p>
         </div>
       </a>
     </template>

scripts/selftest.sh

@@ -24,7 +24,7 @@ trap cleanup EXIT
 cd "${ROOT_DIR}"
 
 echo "[selftest] gofmt"
-gofmt -w backend/main.go backend/handlers/api.go backend/models/db.go backend/services/cse.go backend/services/gemini.go backend/services/gemini_test.go
+gofmt -w backend/main.go backend/handlers/api.go backend/models/db.go backend/services/cse.go backend/services/cse_test.go backend/services/gemini.go backend/services/gemini_test.go
 
 echo "[selftest] python syntax"
 python3 -m py_compile worker/downloader.py scripts/mock_searxng.py