docs: expand .env example to show max/large values; add SUMM_TIMEOUT and summarizer tunables\n\nfeat: summarizer improvements\n- readability extraction for articles\n- image links passed to model as vision inputs\n- configurable max groups/links/bytes and timeout\n- higher default ceilings; resilient fallback summary

internal/summarizer/openai.go

@@ -4,10 +4,14 @@ import (
 	"context"
 	"io"
 	"net/http"
+	"net/url"
 	"regexp"
+	"sort"
+	"strconv"
 	"strings"
 	"time"
 
+	readability "github.com/go-shiori/go-readability"
 	openai "github.com/sashabaranov/go-openai"
 
 	"sojuboy/internal/config"
@@ -25,6 +29,7 @@ type OpenAI struct {
 	linkMaxBytes int
 	groupWindow  time.Duration
 	maxLinks     int
+	maxGroups    int
 }
 
 func NewOpenAI(apiKey, baseURL, model string, maxTokens int) *OpenAI {
@@ -40,6 +45,7 @@ func (o *OpenAI) ApplyConfig(cfg config.Config) {
 	o.linkMaxBytes = cfg.SummLinkMaxBytes
 	o.groupWindow = cfg.SummGroupWindow
 	o.maxLinks = cfg.SummMaxLinks
+	o.maxGroups = cfg.SummMaxGroups
 }
 
 func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Message, window time.Duration) (string, error) {
@@ -54,11 +60,25 @@ func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Mes
 
 	// 1) Group multiline posts from same author within groupWindow
 	grouped := groupMessages(msgs, o.groupWindow)
+	// Apply group cap if configured (>0). 0 means no cap.
+	if o.maxGroups > 0 && len(grouped) > o.maxGroups {
+		grouped = grouped[len(grouped)-o.maxGroups:]
+	}
 
-	// 2) Extract links and optionally fetch a small amount of content
+	// 2) Extract links and optionally fetch content
 	links := extractLinks(grouped)
-	if o.followLinks && len(links) > 0 {
-		links = fetchLinkSnippets(ctx, links, o.linkTimeout, o.linkMaxBytes, o.maxLinks)
+	// Split image vs non-image
+	var imageURLs []string
+	var nonImageLinks []linkSnippet
+	for _, l := range links {
+		if isImageURL(l.url) {
+			imageURLs = append(imageURLs, l.url)
+		} else {
+			nonImageLinks = append(nonImageLinks, l)
+		}
+	}
+	if o.followLinks && len(nonImageLinks) > 0 {
+		nonImageLinks = fetchLinkSnippets(ctx, nonImageLinks, o.linkTimeout, o.linkMaxBytes, o.maxLinks)
 	}
 
 	// 3) Build a concise, natural prompt
@@ -76,9 +96,9 @@ func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Mes
 		b.WriteString(g.text)
 		b.WriteString("\n")
 	}
-	if len(links) > 0 {
+	if len(nonImageLinks) > 0 {
 		b.WriteString("\nReferenced content (snippets):\n")
-		for _, ln := range links {
+		for _, ln := range nonImageLinks {
 			b.WriteString("- ")
 			b.WriteString(ln.url)
 			b.WriteString(" → ")
@@ -101,11 +121,25 @@ func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Mes
 	}
 	reasoningLike := strings.HasPrefix(model, "gpt-5") || strings.HasPrefix(model, "o1") || strings.Contains(model, "reasoning")
 
+	// Build multimodal user message parts
+	userParts := []openai.ChatMessagePart{{Type: openai.ChatMessagePartTypeText, Text: prompt}}
+	// Limit images to o.maxLinks to avoid overloading
+	maxImgs := o.maxLinks
+	if len(imageURLs) > maxImgs {
+		imageURLs = imageURLs[:maxImgs]
+	}
+	for _, u := range imageURLs {
+		userParts = append(userParts, openai.ChatMessagePart{
+			Type:     openai.ChatMessagePartTypeImageURL,
+			ImageURL: &openai.ChatMessageImageURL{URL: u},
+		})
+	}
+
 	req := openai.ChatCompletionRequest{
 		Model: model,
 		Messages: []openai.ChatCompletionMessage{
 			{Role: openai.ChatMessageRoleSystem, Content: sys},
-			{Role: openai.ChatMessageRoleUser, Content: prompt},
+			{Role: openai.ChatMessageRoleUser, MultiContent: userParts},
 		},
 		MaxCompletionTokens: o.maxTokens,
 	}
@@ -118,9 +152,31 @@ func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Mes
 		return "", err
 	}
 	if len(resp.Choices) == 0 {
-		return "", nil
+		return localFallbackSummary(grouped, append(nonImageLinks, linksFromImages(imageURLs)...)), nil
 	}
-	return strings.TrimSpace(resp.Choices[0].Message.Content), nil
+	out := strings.TrimSpace(resp.Choices[0].Message.Content)
+	if out == "" {
+		return localFallbackSummary(grouped, append(nonImageLinks, linksFromImages(imageURLs)...)), nil
+	}
+	return out, nil
+}
+
+func linksFromImages(imgs []string) []linkSnippet {
+	out := make([]linkSnippet, 0, len(imgs))
+	for _, u := range imgs {
+		out = append(out, linkSnippet{url: u})
+	}
+	return out
+}
+
+func isImageURL(u string) bool {
+	lu := strings.ToLower(u)
+	for _, ext := range []string{".jpg", ".jpeg", ".png", ".gif", ".webp"} {
+		if strings.HasSuffix(lu, ext) {
+			return true
+		}
+	}
+	return false
 }
 
 type linkSnippet struct {
@@ -162,7 +218,16 @@ func extractLinks(msgs []groupedMsg) []linkSnippet {
 			links = append(links, linkSnippet{url: m})
 		}
 	}
-	return links
+	// de-dup
+	saw := make(map[string]bool)
+	dedup := make([]linkSnippet, 0, len(links))
+	for _, l := range links {
+		if !saw[l.url] {
+			saw[l.url] = true
+			dedup = append(dedup, l)
+		}
+	}
+	return dedup
 }
 
 func fetchLinkSnippets(ctx context.Context, links []linkSnippet, timeout time.Duration, maxBytes int, maxLinks int) []linkSnippet {
@@ -190,15 +255,76 @@ func fetchLinkSnippets(ctx context.Context, links []linkSnippet, timeout time.Du
 			if err != nil || len(b) == 0 {
 				return
 			}
-			// naive text cleanup
 			text := string(b)
+			// Try readability for cleaner article text
+			if baseURL, perr := url.Parse(ln.url); perr == nil {
+				if art, err := readability.FromReader(strings.NewReader(text), baseURL); err == nil {
+					if at := strings.TrimSpace(art.TextContent); at != "" {
+						text = at
+					}
+				}
+			}
 			text = strings.ReplaceAll(text, "\r", "")
 			text = strings.TrimSpace(text)
-			if len(text) > 800 {
-				text = text[:800]
+			if len(text) > 2000 {
+				text = text[:2000]
 			}
 			out = append(out, linkSnippet{url: ln.url, snippet: text})
 		}()
 	}
 	return out
 }
+
+func localFallbackSummary(grouped []groupedMsg, links []linkSnippet) string {
+	if len(grouped) == 0 {
+		return ""
+	}
+	// simple counts
+	authors := map[string]int{}
+	for _, g := range grouped {
+		authors[g.author]++
+	}
+	authorList := make([]string, 0, len(authors))
+	for a := range authors {
+		authorList = append(authorList, a)
+	}
+	sort.Strings(authorList)
+	var b strings.Builder
+	b.WriteString("Summary (fallback)\n")
+	b.WriteString("- Messages: ")
+	b.WriteString(strconvI(len(grouped)))
+	b.WriteString(" groups by ")
+	b.WriteString(strconvI(len(authors)))
+	b.WriteString(" authors\n")
+	if len(links) > 0 {
+		b.WriteString("- Links: ")
+		for i, l := range links {
+			if i > 0 {
+				b.WriteString(", ")
+			}
+			b.WriteString(l.url)
+		}
+		b.WriteString("\n")
+	}
+	// include last few grouped lines as a teaser
+	tail := grouped
+	if len(tail) > 5 {
+		tail = tail[len(tail)-5:]
+	}
+	for _, g := range tail {
+		b.WriteString("• ")
+		b.WriteString(g.author)
+		b.WriteString(": ")
+		line := g.text
+		if len(line) > 200 {
+			line = line[:200] + "…"
+		}
+		b.WriteString(line)
+		b.WriteString("\n")
+	}
+	return strings.TrimSpace(b.String())
+}
+
+func strconvI(n int) string {
+	return strconv.Itoa(n)
+}