feat: add reading order option to PDF OCR

Detect reading order keywords (縦書き/横書き/vertical/horizontal etc.)
from message content and pass --reading_order to yomitoku CLI.
Falls back to config default, then omits the flag (yomitoku auto).

- Add ReadingOrder field to OCRConfig
- Add detectReadingOrder() with keyword matching
- Thread readingOrder through processPDFsInMessages → ocrPDF
- Include reading order in cache hash for separate variants
- Update Phase 1/2 hint messages to mention 縦書き/横書き
- Add TestDetectReadingOrder

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pkg/agent/loop_media.go

@@ -438,8 +438,42 @@ func wantFigures(content string) bool {
 	return false
 }
 
+// readingOrderKeywords maps message keywords to yomitoku --reading_order values.
+//
+//nolint:gosmopolitan // intentional CJK keywords for Japanese users
+var readingOrderKeywords = []struct {
+	keyword string
+	order   string
+}{
+	{"right2left", "right2left"},
+	{"top2bottom", "top2bottom"},
+	{"left2right", "left2right"},
+	{"縦書き", "right2left"},
+	{"たてがき", "right2left"},
+	{"vertical", "right2left"},
+	{"横書き", "top2bottom"},
+	{"よこがき", "top2bottom"},
+	{"horizontal", "top2bottom"},
+}
+
+// detectReadingOrder returns the reading order specified in the message content.
+// Falls back to the configured default, then "auto".
+func detectReadingOrder(content string, cfgDefault string) string {
+	lower := strings.ToLower(content)
+	for _, kw := range readingOrderKeywords {
+		if strings.Contains(lower, kw.keyword) {
+			return kw.order
+		}
+	}
+	if cfgDefault != "" {
+		return cfgDefault
+	}
+	return "auto"
+}
+
 const pdfHintMessage = "PDF OCR in progress. " +
-	"Tip: include \"figures\" or \"\u56f3\u7248\" in your message to extract images and in-figure text."
+	"Tip: include \"figures\" or \"\u56f3\u7248\" to extract images. " +
+	"Add \"\u7e26\u66f8\u304d\" or \"\u6a2a\u66f8\u304d\" to set reading order."
 
 // processPDFsInMessages finds [file:/path.pdf] tags in messages and replaces
 // them with [document: preview... (full: /path/to.md, N pages)] tags after
@@ -456,8 +490,13 @@ func (al *AgentLoop) processPDFsInMessages(
 			continue
 		}
 		withFigures := wantFigures(m.Content)
+		var cfgRO string
+		if ocrCfg != nil {
+			cfgRO = ocrCfg.ReadingOrder
+		}
+		readingOrder := detectReadingOrder(m.Content, cfgRO)
 		result[i].Content = al.replacePDFTags(
-			ctx, m.Content, ocrCfg, channel, chatID, withFigures,
+			ctx, m.Content, ocrCfg, channel, chatID, withFigures, readingOrder,
 		)
 	}
 
@@ -470,7 +509,7 @@ const pdfTagPrefix = "[file:"
 // replacePDFTags finds [file:*.pdf] tags and replaces them with OCR results.
 func (al *AgentLoop) replacePDFTags(
 	ctx context.Context, content string, ocrCfg *config.OCRConfig,
-	channel, chatID string, withFigures bool,
+	channel, chatID string, withFigures bool, readingOrder string,
 ) string {
 	var out strings.Builder
 	rest := content
@@ -494,7 +533,7 @@ func (al *AgentLoop) replacePDFTags(
 		out.WriteString(rest[:idx])
 
 		if strings.HasSuffix(strings.ToLower(path), ".pdf") {
-			out.WriteString(al.ocrPDF(ctx, path, ocrCfg, channel, chatID, withFigures))
+			out.WriteString(al.ocrPDF(ctx, path, ocrCfg, channel, chatID, withFigures, readingOrder))
 		} else {
 			out.WriteString(tag)
 		}
@@ -508,9 +547,10 @@ func (al *AgentLoop) replacePDFTags(
 // ocrPDF runs OCR on a PDF file and returns a document tag with preview.
 // Uses the media cache to avoid redundant OCR runs.
 // When withFigures is true, --figure and --figure_letter flags are added.
+// readingOrder is passed as --reading_order to yomitoku.
 func (al *AgentLoop) ocrPDF(
 	ctx context.Context, pdfPath string, ocrCfg *config.OCRConfig,
-	channel, chatID string, withFigures bool,
+	channel, chatID string, withFigures bool, readingOrder string,
 ) string {
 	// Hash the file content for cache lookup.
 	// Include figure mode in the hash so both variants are cached separately.
@@ -523,6 +563,9 @@ func (al *AgentLoop) ocrPDF(
 	if withFigures {
 		hashInput = append(hashInput, []byte(":figures")...)
 	}
+	if readingOrder != "" && readingOrder != "auto" {
+		hashInput = append(hashInput, []byte(":ro="+readingOrder)...)
+	}
 	hash := mediacache.HashData(hashInput)
 
 	// Check cache (both text extraction and OCR)
@@ -564,8 +607,12 @@ func (al *AgentLoop) ocrPDF(
 	}
 
 	modeLabel := "Processing PDF"
-	if withFigures {
+	if withFigures && readingOrder != "" && readingOrder != "auto" {
+		modeLabel = fmt.Sprintf("Processing PDF (figures, %s)", readingOrder)
+	} else if withFigures {
 		modeLabel = "Processing PDF (with figures)"
+	} else if readingOrder != "" && readingOrder != "auto" {
+		modeLabel = fmt.Sprintf("Processing PDF (%s)", readingOrder)
 	}
 	indicator := al.processingIndicator(ctx, channel, chatID,
 		fmt.Sprintf("%s (0/%s)...", modeLabel, totalStr))
@@ -580,11 +627,14 @@ func (al *AgentLoop) ocrPDF(
 	cmdCtx, cmdCancel := context.WithTimeout(ctx, timeout)
 	defer cmdCancel()
 
-	args := make([]string, 0, len(ocrCfg.Args)+6)
+	args := make([]string, 0, len(ocrCfg.Args)+8)
 	args = append(args, ocrCfg.Args...)
 	if withFigures {
 		args = append(args, "--figure", "--figure_letter")
 	}
+	if readingOrder != "" && readingOrder != "auto" {
+		args = append(args, "--reading_order", readingOrder)
+	}
 	args = append(args, pdfPath, "-o", outputDir)
 
 	cmd := exec.CommandContext(cmdCtx, ocrCfg.Command, args...)
@@ -605,6 +655,7 @@ func (al *AgentLoop) ocrPDF(
 		"path":          pdfPath,
 		"pages":         totalStr,
 		"cmd":           ocrCfg.Command,
+		"reading_order": readingOrder,
 	})
 
 	if startErr := cmd.Start(); startErr != nil {

pkg/agent/loop_media_test.go

@@ -151,7 +151,7 @@ func TestFormatDocumentTag_UnknownPages(t *testing.T) {
 func TestReplacePDFTags_NoPDF(t *testing.T) {
 	al := &AgentLoop{}
 	content := "Check this out [file:/path/to/audio.mp3]"
-	result := al.replacePDFTags(t.Context(), content, &config.OCRConfig{Command: "echo"}, "", "", false)
+	result := al.replacePDFTags(t.Context(), content, &config.OCRConfig{Command: "echo"}, "", "", false, "auto")
 	if result != content {
 		t.Errorf("non-PDF should be unchanged, got %q", result)
 	}
@@ -160,7 +160,7 @@ func TestReplacePDFTags_NoPDF(t *testing.T) {
 func TestReplacePDFTags_NoTags(t *testing.T) {
 	al := &AgentLoop{}
 	content := "Hello world"
-	result := al.replacePDFTags(t.Context(), content, &config.OCRConfig{Command: "echo"}, "", "", false)
+	result := al.replacePDFTags(t.Context(), content, &config.OCRConfig{Command: "echo"}, "", "", false, "auto")
 	if result != content {
 		t.Errorf("no tags should be unchanged, got %q", result)
 	}
@@ -178,6 +178,33 @@ func TestProcessPDFs_NilOCR(t *testing.T) {
 	}
 }
 
+func TestDetectReadingOrder(t *testing.T) {
+	tests := []struct {
+		content    string
+		cfgDefault string
+		want       string
+	}{
+		{"この文書を読んで", "", "auto"},
+		{"縦書きで読んで", "", "right2left"},
+		{"横書きのPDF", "", "top2bottom"},
+		{"vertical layout", "", "right2left"},
+		{"horizontal doc", "", "top2bottom"},
+		{"right2left please", "", "right2left"},
+		{"top2bottom mode", "", "top2bottom"},
+		{"left2right table", "", "left2right"},
+		{"たてがきの文書", "", "right2left"},
+		{"よこがきの文書", "", "top2bottom"},
+		{"plain message", "right2left", "right2left"},
+		{"plain message", "", "auto"},
+		{"縦書き", "top2bottom", "right2left"}, // message keyword overrides config default
+	}
+	for _, tt := range tests {
+		if got := detectReadingOrder(tt.content, tt.cfgDefault); got != tt.want {
+			t.Errorf("detectReadingOrder(%q, %q) = %q, want %q", tt.content, tt.cfgDefault, got, tt.want)
+		}
+	}
+}
+
 func TestWantFigures(t *testing.T) {
 	tests := []struct {
 		content string

pkg/agent/loop_pdf_wait.go

@@ -17,7 +17,7 @@ const pdfFollowUpWait = 5 * time.Second
 
 // pdfFollowUpHint is sent when a PDF arrives without text.
 const pdfFollowUpHint = "PDF received. You can send OCR options " +
-	"(e.g. \"figures\" / \"\u56f3\u7248\") within a few seconds, or processing will start automatically."
+	"(e.g. \"figures\" / \"\u56f3\u7248\", \"\u7e26\u66f8\u304d\" / \"\u6a2a\u66f8\u304d\") within a few seconds, or processing will start automatically."
 
 // pdfCancelKeywords triggers OCR cancellation when found in a message
 // received during Phase 2 (OCR in progress).

pkg/config/config.go

@@ -251,6 +251,7 @@ type OCRConfig struct {
 	Args         []string          `json:"args,omitempty"`
 	Env          map[string]string `json:"env,omitempty"`
 	Timeout      int               `json:"timeout,omitempty"`
+	ReadingOrder string            `json:"reading_order,omitempty"`
 }
 
 // GetOCRTimeout returns the configured timeout or default (600s = 10min).