.env.example

@@ -90,3 +90,23 @@ DISCORD_REDIRECT_URI=
 # HTTP handler 500s any /json/version request whose Host header isn't an IP or
 # "localhost", which silently breaks every kagane poll.
 # BROWSER_WS_URL=ws://172.28.0.10:9222
+
+# Clock zone the headless browser reports. A UTC clock is itself the bot
+# signal — Cloudflare treats it as the datacenter default — and kagane's
+# challenge then never clears. Measured 2026-08-08, identical container, one
+# Indonesian egress IP: UTC never cleared in 60s (twice); Asia/Jakarta and
+# America/New_York both cleared in 4s. So any real zone works; it does not
+# have to match the IP's country, it just must not be UTC.
+#
+# Unset falls back to the host's /etc/timezone, which is a real zone whenever
+# the host clock is set to local time. Set this when the host runs UTC — a UTC
+# server is exactly the case that fails. Only the browser sidecar reads it —
+# the backend's own zone is API_TZ below, and is cosmetic.
+# BROWSER_TZ=Asia/Jakarta
+
+# Zone the backend stamps its log lines in. Cosmetic only — it exists so the
+# API's logs read on the same clock as the browser sidecar's. Nothing else in
+# the service has a zone: bookmark timestamps are unix ms, and the two real
+# time columns are timestamptz. Defaults to Asia/Jakarta; set to UTC for the
+# conventional server default.
+# API_TZ=Asia/Jakarta

AGENTS.md

@@ -20,6 +20,9 @@ Userscript targets **Violentmonkey**, so `GM_*` APIs available, but stay GM-free
 - Userscript run in **isolated world**, so embedded API token safe from site's JS.
 - Cloudflare's block on manga sites **IP-reputation-based, not universal — and not reliably reproducible.** Verified 2026-07-26: plain `curl` from both CGNAT dev machine *and* deployed VPS got clean 200s with real HTML on both asurascans.com and demonicscans.org (homepage, series, chapter pages) — no interactive Turnstile challenge from either IP at test time. Contradicts earlier untested assumption CGNAT dev IP blocked; wasn't, at least this date. Treat "does curl work right now" as live, time-varying fact to re-check, not fixed property of machine — Cloudflare's bot scoring can flip previously-clean IP without notice. Backend fetcher still needs graceful-degrade path for when challenged, and adapters should be **verified against live pages** (Playwright MCP, on-device devtools, direct probe) before finalizing, not assumed from single earlier test.
 - **kagane.to and novelfull.com are the exception to the above** — both sit behind a Cloudflare JavaScript challenge no TLS fingerprint clears, so the backend polls them over CDP (`BROWSER_WS_URL`) and skips them entirely when that's unset. The four other sites poll fine over plain TLS.
+- **The CDP sidecar must look like a real browser, and stock headless images don't.** Measured 2026-08-08 against kagane.to, all from the same IP: `chromedp/headless-shell:stable` never cleared the challenge in 90s (`navigator.webdriver` true, empty plugin list, Chromium-branded client hints — suppressing `webdriver` alone changed nothing); `zenika/alpine-chrome` ships Chrome 124, refused outright; real Chrome with the default `--headless=new` UA never cleared, because the UA says `HeadlessChrome`; real Chrome with a stock UA **and** a non-UTC clock zone cleared in ~4s. Hence `chrome/` — a Debian image with `google-chrome-stable`, a version-derived UA, and `TZ`/`BROWSER_TZ`. Chrome reads the zone *name* through ICU from `/etc/localtime`'s symlink target, ignoring the file's contents, so mounting the host's `/etc/localtime` does **not** work; `/etc/timezone` is mounted instead.
+- **UTC is the tell, not a country mismatch.** A UTC clock is the datacenter default, so Cloudflare scores it as one; any real zone clears. Measured 2026-08-08, identical container, one Indonesian egress IP: UTC never cleared in 60s (twice), while `Asia/Jakarta` **and** `America/New_York` both cleared in 4s. An earlier note here claimed the zone had to match the egress IP's country — that was wrong, inferred from the host clock (`Asia/Bangkok`) rather than the measured egress. `BROWSER_TZ` therefore needs a plausible zone, not a geolocated one.
+- **A challenged page needs the tab kept open.** The interstitial takes seconds to solve and only then writes clearance into the browser's shared cookie jar. Navigate-read-close never clears anything; `BrowserFetcher.run` holds one tab and re-reads until the payload arrives.
 
 ## Architecture
 
@@ -37,7 +40,12 @@ Backend (`cd backend`):
 - Single test: `go test -run TestName ./...`
 - Build static binary: `CGO_ENABLED=0 go build`
 
-Local stack: `docker compose up` (bookmark-api + postgres + headless-shell; `postgres-data` named volume, `restart: unless-stopped`).
+Local stack: `docker compose up` (bookmark-api + postgres + headless-shell; `postgres-data` named volume, `restart: unless-stopped`). The `headless-shell` service keeps its name but now builds `chrome/` — real Google Chrome, for the reason in the hard constraints above.
+
+Live CDP proof (needs a sidecar and network, skipped otherwise):
+`SMOKE_BROWSER_WS_URL=ws://<host>:<port> go test -run TestSmokeKagane ./internal/latest`
+— fetches a real kagane cover and chapter list. A red run means the challenge is
+not clearing from this IP, which is a live fact to re-check, not necessarily a defect.
 
 Smoke test: `curl` endpoints with `Authorization: Bearer <token>`; confirm `OPTIONS` preflight return CORS headers and `/healthz` return 200.
 

backend/AGENTS.md

@@ -126,9 +126,20 @@ Guidance for OpenCode (and Claude Code) working under `backend/`. See root `AGEN
   `/userscript/novel-bookmark.user.js`, both supplied by bindmount; the
   `__API_TOKEN__` placeholder inside them is substituted with the requesting
   Reader's credential at serve time).
-  `BROWSER_WS_URL` (headless-shell CDP endpoint for kagane and novelfull;
+  `BROWSER_WS_URL` (CDP endpoint of the `chrome/` sidecar, used by the poller
-  unset disables browser polling and leaves those sites to the userscript
+  for kagane and novelfull *and* by the web UI's kagane cover proxy; unset
-  alone).
+  disables browser polling and serves 404 from the proxy, leaving those sites
+  to the userscript alone).
+- **kagane covers are proxied, not hot-linked:** kagane serves cover images
+  behind the same challenge as its pages and with
+  `cross-origin-resource-policy: same-origin`, so no `<img>` on the web UI's
+  origin can load one — not even from a browser holding the clearance cookie
+  (verified 2026-08-08). `Bookmark.CoverURL` rewrites a stored kagane
+  `og:image` to `/img/kagane/{id}`, served by `internal/web/cover.go` through
+  `latest.BrowserFetcher.Image` and memoised in-process. The templates render
+  `.CoverURL`, never `.Cover`. The id is matched against a UUID regex before it
+  reaches the browser: the stored value is client-supplied, so an unchecked one
+  is an SSRF primitive pointed at the deployment's own network.
 - **Web UI also owns:** session-gated `GET /install/{manga,novel}-bookmark.user.js`
   (renders the bindmounted script with the acting Reader's derived credential
   substituted in — the credential never appears in page markup, the address

backend/cover_test.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"sync/atomic"
+	"testing"
+)
+
+// fakeCovers stands in for the headless browser. It counts calls so the test
+// can prove the cache spares the browser a second navigation.
+type fakeCovers struct {
+	body        []byte
+	contentType string
+	err         error
+	calls       atomic.Int32
+	lastID      atomic.Value
+}
+
+func (f *fakeCovers) Image(_ context.Context, imageID string) ([]byte, string, error) {
+	f.calls.Add(1)
+	f.lastID.Store(imageID)
+	if f.err != nil {
+		return nil, "", f.err
+	}
+	return f.body, f.contentType, nil
+}
+
+const testCoverID = "019fe11a-84c3-7fc3-a84b-88787374b617"
+
+func getCover(t *testing.T, srv http.Handler, path string, cookie *http.Cookie) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, path, nil)
+	if cookie != nil {
+		req.AddCookie(cookie)
+	}
+	rr := httptest.NewRecorder()
+	srv.ServeHTTP(rr, req)
+	return rr
+}
+
+// kagane serves its covers behind a Cloudflare challenge and with
+// cross-origin-resource-policy: same-origin, so the UI can only show one by
+// re-serving the bytes from its own origin.
+func TestKaganeCoverProxiesAndCaches(t *testing.T) {
+	cf := &fakeCovers{body: []byte("\x00webp-bytes"), contentType: "image/webp"}
+	cfg := testConfig()
+	cfg.Covers = cf
+	srv, st := newWebTestServer(t, cfg)
+	cookie := sessionCookie(t, st)
+
+	for i := range 2 {
+		rr := getCover(t, srv, "/img/kagane/"+testCoverID, cookie)
+		if rr.Code != http.StatusOK {
+			t.Fatalf("request %d: status = %d, want 200", i, rr.Code)
+		}
+		if got := rr.Body.String(); got != string(cf.body) {
+			t.Fatalf("request %d: body = %q, want %q", i, got, cf.body)
+		}
+		if got := rr.Header().Get("Content-Type"); got != "image/webp" {
+			t.Fatalf("request %d: Content-Type = %q, want image/webp", i, got)
+		}
+	}
+	if got := cf.calls.Load(); got != 1 {
+		t.Fatalf("fetcher called %d times, want 1 — the second read must come from the cache", got)
+	}
+	if got := cf.lastID.Load(); got != testCoverID {
+		t.Fatalf("fetched image id = %v, want %s", got, testCoverID)
+	}
+}
+
+// The proxy reaches a headless browser, so it is not open to the internet.
+func TestKaganeCoverRequiresSession(t *testing.T) {
+	cf := &fakeCovers{body: []byte("x"), contentType: "image/webp"}
+	cfg := testConfig()
+	cfg.Covers = cf
+	srv, _ := newWebTestServer(t, cfg)
+
+	rr := getCover(t, srv, "/img/kagane/"+testCoverID, nil)
+	if rr.Code != http.StatusUnauthorized {
+		t.Fatalf("status = %d, want 401", rr.Code)
+	}
+	if got := cf.calls.Load(); got != 0 {
+		t.Fatalf("fetcher called %d times for an unauthenticated request, want 0", got)
+	}
+}
+
+func TestKaganeCoverRejectsBadInput(t *testing.T) {
+	cases := []struct {
+		name  string
+		id    string
+		fetch *fakeCovers
+	}{
+		{
+			"an id that is not a uuid never reaches the browser",
+			"solo-leveling",
+			&fakeCovers{body: []byte("x"), contentType: "image/webp"},
+		},
+		{
+			"a uuid-shaped id with a trailing segment is rejected whole",
+			testCoverID + "x",
+			&fakeCovers{body: []byte("x"), contentType: "image/webp"},
+		},
+		{
+			"a challenged fetch is a missing cover",
+			testCoverID,
+			&fakeCovers{err: errors.New("challenge held")},
+		},
+		{
+			"a content type outside the image set is not echoed back",
+			testCoverID,
+			&fakeCovers{body: []byte("<script>"), contentType: "text/html"},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := testConfig()
+			cfg.Covers = tc.fetch
+			srv, st := newWebTestServer(t, cfg)
+			rr := getCover(t, srv, "/img/kagane/"+tc.id, sessionCookie(t, st))
+			if rr.Code != http.StatusNotFound {
+				t.Fatalf("status = %d, want 404", rr.Code)
+			}
+		})
+	}
+}
+
+// ServeMux path-cleans a traversal into a redirect before the handler runs, so
+// the guarantee to pin down is that no request shaped like one ever gets bytes.
+func TestKaganeCoverTraversalServesNothing(t *testing.T) {
+	cf := &fakeCovers{body: []byte("secret"), contentType: "image/webp"}
+	cfg := testConfig()
+	cfg.Covers = cf
+	srv, st := newWebTestServer(t, cfg)
+
+	rr := getCover(t, srv, "/img/kagane/../../etc/passwd", sessionCookie(t, st))
+	if rr.Code == http.StatusOK {
+		t.Fatalf("status = 200, want anything but a served body")
+	}
+	if got := cf.calls.Load(); got != 0 {
+		t.Fatalf("fetcher called %d times for a traversal, want 0", got)
+	}
+}
+
+// Without BROWSER_WS_URL there is no fetcher, and the endpoint must answer
+// rather than reach for a nil one.
+func TestKaganeCoverWithoutFetcher(t *testing.T) {
+	srv, st := newWebTestServer(t, testConfig())
+	rr := getCover(t, srv, "/img/kagane/"+testCoverID, sessionCookie(t, st))
+	if rr.Code != http.StatusNotFound {
+		t.Fatalf("status = %d, want 404", rr.Code)
+	}
+}

backend/internal/latest/browser.go

@@ -2,7 +2,9 @@ package latest
 
 import (
 	"context"
+	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/url"
 	"regexp"
@@ -22,6 +24,12 @@ const challengeTimeout = 45 * time.Second
 
 var kaganeSeriesRe = regexp.MustCompile(`^/series/([0-9a-f-]{36})/?$`)
 
+// kaganeImageIDRe pins the only path segment Image interpolates into an
+// outbound URL. The id arrives from a stored cover URL, which a client
+// supplied, so it is matched rather than trusted: a headless browser is a
+// strong SSRF primitive.
+var kaganeImageIDRe = regexp.MustCompile(`^[0-9a-f-]{36}$`)
+
 // BrowserFetcher retrieves pages through a remote headless Chrome over the
 // DevTools Protocol.
 //
@@ -91,23 +99,6 @@ func (f *BrowserFetcher) Get(ctx context.Context, seriesURL string) (string, int
 		return "", 0, fmt.Errorf("not a fetchable browser series url: %q", seriesURL)
 	}
 
-	f.mu.Lock()
-	defer f.mu.Unlock()
-
-	ctx, cancel := context.WithTimeout(ctx, challengeTimeout)
-	defer cancel()
-	// A fresh tab per fetch, closed on return, so one wedged page cannot
-	// poison later polls.
-	tabCtx, cancelTab := chromedp.NewContext(f.allocCtx)
-	defer cancelTab()
-	// Bind the caller's deadline to the tab.
-	tabCtx, cancelDeadline := context.WithCancel(tabCtx)
-	defer cancelDeadline()
-	go func() {
-		<-ctx.Done()
-		cancelDeadline()
-	}()
-
 	var body string
 	// kagane's chapter list is only in its JSON API, which must be called from
 	// inside the page so the request carries the clearance cookie. novelfull
@@ -123,24 +114,134 @@ func (f *BrowserFetcher) Get(ctx context.Context, seriesURL string) (string, int
 		)
 	}
 
-	err := chromedp.Run(tabCtx,
+	// novelfull's payload is the DOM itself, and the interstitial has a DOM
-		chromedp.Navigate(seriesURL),
+	// too, so "we have an answer" has to exclude it explicitly. kagane's
-		// The challenge reloads the page itself when it passes; waiting for the
+	// in-page fetch just fails while challenged, which is already the signal.
-		// site's own root element is what tells us we are through it.
+	done := func() bool { return body != "" && (isKagane || !isInterstitial(body)) }
-		chromedp.WaitReady("body", chromedp.ByQuery),
+	if err := f.run(ctx, seriesURL, read, done); err != nil {
-		read,
+		// Challenge never cleared, or the API refused. Indistinguishable from
-	)
+		// here and handled identically by the caller.
-	if err != nil {
+		if errors.Is(err, errChallengeHeld) {
+			return "", 403, nil
+		}
 		return "", 0, fmt.Errorf("browser fetch %q: %w", seriesURL, err)
 	}
-	if body == "" {
-		// Challenge still up, or the API refused. Indistinguishable from here
-		// and handled identically by the caller.
-		return "", 403, nil
-	}
 	return body, 200, nil
 }
 
+// Image retrieves one kagane cover as raw bytes and its content type.
+//
+// It exists because kagane serves covers behind the same challenge as its
+// pages *and* with `cross-origin-resource-policy: same-origin`, so an <img> on
+// the web UI's origin cannot load one even from a browser that already holds
+// the clearance cookie (verified 2026-08-08). Proxying is the only route.
+//
+// The image URL is navigated to rather than fetched from some other kagane
+// page: the challenge only runs on a top-level navigation, and once it clears
+// the document *is* the image, so a same-origin fetch of location.href reads
+// it straight back out of the cache.
+//
+// The challenge is not solved by the first read: WaitReady("body") is satisfied
+// by the interstitial too. run holds the tab open until the in-page fetch
+// succeeds, which is what gives the challenge script the seconds it needs.
+func (f *BrowserFetcher) Image(ctx context.Context, imageID string) ([]byte, string, error) {
+	if !kaganeImageIDRe.MatchString(imageID) {
+		return nil, "", fmt.Errorf("not a kagane image id: %q", imageID)
+	}
+	var dataURL string
+	err := f.run(ctx, "https://kagane.to/api/v2/image/"+imageID+"/compressed",
+		chromedp.Evaluate(`fetch(location.href).then(r => r.ok
+			? r.blob().then(b => new Promise(res => {
+					const fr = new FileReader();
+					fr.onload = () => res(fr.result);
+					fr.readAsDataURL(b);
+				}))
+			: "")`, &dataURL, awaitPromise),
+		func() bool { return dataURL != "" })
+	if err != nil {
+		return nil, "", fmt.Errorf("browser image %s: %w", imageID, err)
+	}
+	// "data:image/webp;base64,<payload>".
+	head, payload, ok := strings.Cut(dataURL, ";base64,")
+	if !ok {
+		return nil, "", fmt.Errorf("browser image %s: not a data url", imageID)
+	}
+	raw, err := base64.StdEncoding.DecodeString(payload)
+	if err != nil {
+		return nil, "", fmt.Errorf("browser image %s: %w", imageID, err)
+	}
+	return raw, strings.TrimPrefix(head, "data:"), nil
+}
+
+// errChallengeHeld reports that the budget ran out with the interstitial still
+// up. Distinct from a transport failure: it means "this site said no", which
+// the poller answers with a 403 and its ordinary cooldown.
+var errChallengeHeld = errors.New("challenge held")
+
+// challengePollInterval paces re-reads while a challenge solves itself.
+const challengePollInterval = 2 * time.Second
+
+// isInterstitial reports whether html is Cloudflare's challenge page rather
+// than the site's own. Matched on the challenge runtime's script path, which is
+// stable across the interstitial's wording and locale — the visible "Just a
+// moment..." title is neither.
+func isInterstitial(html string) bool {
+	return strings.Contains(html, "/cdn-cgi/challenge-platform/")
+}
+
+// run navigates to target and re-reads until done reports an answer, bounded by
+// challengeTimeout and by the caller's own deadline, in a tab that is closed on
+// return so one wedged page cannot poison later calls.
+//
+// Holding the tab open across re-reads is the whole point. A Cloudflare
+// interstitial needs several seconds of a live page to solve itself and write
+// clearance into the browser's shared cookie jar; reading once and closing the
+// tab — which is what this did before 2026-08-08 — never gives it that window,
+// so every fetch lands on the interstitial and the clearance that would have
+// unblocked all the later ones is never obtained.
+func (f *BrowserFetcher) run(ctx context.Context, target string, read chromedp.Action, done func() bool) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	ctx, cancel := context.WithTimeout(ctx, challengeTimeout)
+	defer cancel()
+	tabCtx, cancelTab := chromedp.NewContext(f.allocCtx)
+	defer cancelTab()
+	// Bind the caller's deadline to the tab.
+	tabCtx, cancelDeadline := context.WithCancel(tabCtx)
+	defer cancelDeadline()
+	go func() {
+		<-ctx.Done()
+		cancelDeadline()
+	}()
+
+	if err := chromedp.Run(tabCtx,
+		chromedp.Navigate(target),
+		chromedp.WaitReady("body", chromedp.ByQuery),
+	); err != nil {
+		return err
+	}
+
+	var lastErr error
+	for {
+		// The challenge reloads the page when it passes, which tears down the
+		// execution context mid-read. That is a retry, not a failure.
+		if err := chromedp.Run(tabCtx, read); err != nil {
+			lastErr = err
+		} else if done() {
+			return nil
+		}
+		select {
+		case <-ctx.Done():
+			if lastErr != nil {
+				return fmt.Errorf("%w (last read: %v)", errChallengeHeld, lastErr)
+			}
+			return errChallengeHeld
+		case <-time.After(challengePollInterval):
+		}
+	}
+}
+
 // kaganeAPIURL maps a stored series_url to the JSON endpoint carrying its
 // chapter list. Returning false for anything else is a second line of defence
 // behind fetchableSeriesURL: a headless browser is a strong SSRF primitive and

backend/internal/latest/smoke_image_test.go

@@ -0,0 +1,91 @@
+package latest
+
+import (
+	"context"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+)
+
+// TestSmokeKaganeImage is the live proof that the cover proxy's fetch actually
+// clears Cloudflare and returns image bytes. It needs a real headless Chrome
+// with outbound network, so it runs only when SMOKE_BROWSER_WS_URL is set:
+//
+//	docker run --rm --shm-size=1gb -p 19222:9222 chromedp/headless-shell:stable
+//	SMOKE_BROWSER_WS_URL=ws://127.0.0.1:19222 go test -run TestSmokeKaganeImage ./internal/latest
+func TestSmokeKaganeImage(t *testing.T) {
+	ws := os.Getenv("SMOKE_BROWSER_WS_URL")
+	if ws == "" {
+		t.Skip("SMOKE_BROWSER_WS_URL unset")
+	}
+	const imageID = "019fe11a-84c3-7fc3-a84b-88787374b617" // SP Baby's cover
+
+	// The same URL through a plain client is what the web UI's <img> gets.
+	// Asserting on it keeps the test honest about why the browser is needed.
+	req, err := http.NewRequest(http.MethodGet,
+		"https://kagane.to/api/v2/image/"+imageID+"/compressed", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res, err := (&http.Client{Timeout: 15 * time.Second}).Do(req); err == nil {
+		res.Body.Close()
+		if res.StatusCode == http.StatusOK {
+			t.Log("note: kagane answered a plain request 200 — the challenge is not up right now")
+		}
+	}
+
+	f, err := NewBrowserFetcher(ws)
+	if err != nil {
+		t.Fatalf("NewBrowserFetcher: %v", err)
+	}
+	defer f.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
+	defer cancel()
+	body, contentType, err := f.Image(ctx, imageID)
+	if err != nil {
+		t.Fatalf("Image: %v", err)
+	}
+	if len(body) < 1000 {
+		t.Fatalf("body is %d bytes, want a real image", len(body))
+	}
+	if contentType != "image/webp" {
+		t.Fatalf("content type = %q, want image/webp", contentType)
+	}
+	// WebP files start with "RIFF....WEBP".
+	if string(body[:4]) != "RIFF" || string(body[8:12]) != "WEBP" {
+		t.Fatalf("body is not a WebP: % x", body[:12])
+	}
+	t.Logf("fetched %d bytes of %s", len(body), contentType)
+
+	if _, _, err := f.Image(ctx, "not-a-uuid"); err == nil {
+		t.Fatal("Image accepted a non-uuid id")
+	}
+}
+
+// Control for the test above: the poller's own kagane path, same sidecar. If
+// this fails too, the sidecar is not clearing the challenge at all and the
+// image result says nothing about Image itself.
+func TestSmokeKaganeGet(t *testing.T) {
+	ws := os.Getenv("SMOKE_BROWSER_WS_URL")
+	if ws == "" {
+		t.Skip("SMOKE_BROWSER_WS_URL unset")
+	}
+	f, err := NewBrowserFetcher(ws)
+	if err != nil {
+		t.Fatalf("NewBrowserFetcher: %v", err)
+	}
+	defer f.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
+	defer cancel()
+	body, status, err := f.Get(ctx, "https://kagane.to/series/019fe11a-8670-7cf3-8343-0b02057d3787")
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	t.Logf("status=%d bytes=%d head=%.80q", status, len(body), body)
+	if status != 200 {
+		t.Fatalf("status = %d, want 200 — the sidecar is not clearing the challenge", status)
+	}
+}

backend/internal/store/store.go

@@ -137,6 +137,22 @@ func (b Bookmark) Initial() string {
 	return "?"
 }
 
+// kaganeCoverRe matches the cover URL kagane's og:image carries, which is what
+// the userscript stores for that site.
+var kaganeCoverRe = regexp.MustCompile(`^https://kagane\.to/api/v2/image/([0-9a-f-]{36})/compressed$`)
+
+// CoverURL is the src the web UI puts in an <img>. For every site but kagane
+// that is Cover as stored. kagane serves its images behind a Cloudflare
+// challenge *and* with `cross-origin-resource-policy: same-origin`, so no page
+// on another origin can load one however it asks (verified 2026-08-08); those
+// go through the backend's own proxy instead.
+func (b Bookmark) CoverURL() string {
+	if m := kaganeCoverRe.FindStringSubmatch(b.Cover); m != nil {
+		return "/img/kagane/" + m[1]
+	}
+	return b.Cover
+}
+
 // Library buckets. A bookmark is in exactly one. This cannot be derived from
 // Site: asurascans serves manga and novels from the same /comics/ path, so the
 // userscript that recorded the page is the only party that knows which.

backend/internal/store/store_test.go

@@ -543,6 +543,38 @@ func TestDisplayChapter(t *testing.T) {
 	}
 }
 
+func TestCoverURL(t *testing.T) {
+	cases := []struct {
+		name  string
+		cover string
+		want  string
+	}{
+		{
+			"kagane routes through the proxy",
+			"https://kagane.to/api/v2/image/019fe11a-84c3-7fc3-a84b-88787374b617/compressed",
+			"/img/kagane/019fe11a-84c3-7fc3-a84b-88787374b617",
+		},
+		{
+			"another site is served as stored",
+			"https://gg.asuracomic.net/storage/media/1/conversions/cover.webp",
+			"https://gg.asuracomic.net/storage/media/1/conversions/cover.webp",
+		},
+		{
+			"a lookalike host is not rewritten",
+			"https://evil.example/api/v2/image/019fe11a-84c3-7fc3-a84b-88787374b617/compressed",
+			"https://evil.example/api/v2/image/019fe11a-84c3-7fc3-a84b-88787374b617/compressed",
+		},
+		{"no cover stays empty", "", ""},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := (Bookmark{Cover: tc.cover}).CoverURL(); got != tc.want {
+				t.Errorf("CoverURL() = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
 func TestUpsertKindDefaultsToManga(t *testing.T) {
 	store := newTestStore(t)
 	got, err := store.Upsert(store.OwnerID(), Bookmark{

backend/internal/web/cover.go

@@ -0,0 +1,129 @@
+package web
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"regexp"
+	"sync"
+	"time"
+)
+
+// CoverFetcher retrieves one kagane cover by image id. Satisfied by
+// latest.BrowserFetcher, and nil when BROWSER_WS_URL is unset — which leaves
+// kagane covers exactly as unavailable as they were before this endpoint
+// existed, rather than hanging a request on a fetcher that cannot run.
+type CoverFetcher interface {
+	Image(ctx context.Context, imageID string) (body []byte, contentType string, err error)
+}
+
+// coverIDRe matches the request path segment that becomes part of an outbound
+// URL. The proxy is session-gated, but the id still reaches a headless browser,
+// so it is validated at the boundary rather than passed through.
+var coverIDRe = regexp.MustCompile(`^[0-9a-f-]{36}$`)
+
+// coverTypes is the set of content types the proxy will echo back. A response
+// header sourced from a third party is not repeated verbatim: anything outside
+// this set is treated as "not a cover".
+var coverTypes = map[string]bool{
+	"image/webp": true,
+	"image/jpeg": true,
+	"image/png":  true,
+	"image/avif": true,
+	"image/gif":  true,
+}
+
+// coverTimeout bounds one proxied cover. Shorter than the fetcher's own
+// challenge budget on purpose: a browser page is waiting on this, and a cover
+// that has not arrived by now is better left as a broken slot than as a request
+// holding a connection open.
+const coverTimeout = 20 * time.Second
+
+// coverCacheMax caps the in-memory cover cache. Covers are immutable per image
+// id and a library holds tens of series, so this is a ceiling that is never
+// reached in practice; reaching it clears the map rather than evicting by age.
+//
+// ponytail: flush-on-full, not LRU. Swap it for an LRU if a library ever grows
+// past this and the flush starts costing refetches.
+const coverCacheMax = 500
+
+type cachedCover struct {
+	body        []byte
+	contentType string
+}
+
+type coverCache struct {
+	mu sync.Mutex
+	m  map[string]cachedCover
+}
+
+func (c *coverCache) get(id string) (cachedCover, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	v, ok := c.m[id]
+	return v, ok
+}
+
+func (c *coverCache) put(id string, v cachedCover) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.m == nil || len(c.m) >= coverCacheMax {
+		c.m = make(map[string]cachedCover, coverCacheMax)
+	}
+	c.m[id] = v
+}
+
+// kaganeCover serves a kagane cover from the backend's own origin.
+//
+// kagane answers image requests with a Cloudflare challenge and
+// `cross-origin-resource-policy: same-origin`, so the web UI cannot render one
+// directly under any combination of referrer policy or crossorigin attribute
+// (verified 2026-08-08). Fetching it through the headless browser that already
+// clears the challenge, and re-serving it here, is what puts the bytes on an
+// origin the page may load from.
+//
+// ponytail: covers are fetched on first view, one browser navigation at a time
+// behind the fetcher's mutex, so a first load of a large kagane library
+// trickles in over a few seconds. The cache makes it a one-off. Prefetching
+// during the poll cycle is the upgrade if that ever grates.
+func (h *Handler) kaganeCover(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if !coverIDRe.MatchString(id) {
+		http.NotFound(w, r)
+		return
+	}
+	if h.covers == nil {
+		http.NotFound(w, r)
+		return
+	}
+	if v, ok := h.coverCache.get(id); ok {
+		writeCover(w, v)
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(r.Context(), coverTimeout)
+	defer cancel()
+	body, contentType, err := h.covers.Image(ctx, id)
+	if err != nil {
+		log.Printf("kagane cover %s: %v", id, err)
+		http.NotFound(w, r)
+		return
+	}
+	if !coverTypes[contentType] {
+		log.Printf("kagane cover %s: unexpected content type %q", id, contentType)
+		http.NotFound(w, r)
+		return
+	}
+
+	v := cachedCover{body: body, contentType: contentType}
+	h.coverCache.put(id, v)
+	writeCover(w, v)
+}
+
+// writeCover sends the bytes with a long cache life: an image id names one
+// immutable rendering, so a client that has it never needs to ask again.
+func writeCover(w http.ResponseWriter, v cachedCover) {
+	w.Header().Set("Content-Type", v.contentType)
+	w.Header().Set("Cache-Control", "private, max-age=604800, immutable")
+	w.Write(v.body)
+}

backend/internal/web/templates/card.html

@@ -6,7 +6,7 @@
   <div class="row">
     <a class="cover" href="{{.ContinueURL}}" target="_blank" rel="noopener noreferrer"
        tabindex="-1" aria-hidden="true">
-      {{if .Cover}}<img src="{{.Cover}}" alt="" loading="lazy">
+      {{if .CoverURL}}<img src="{{.CoverURL}}" alt="" loading="lazy">
       {{/* aria-hidden on the cover link is not enough — Chromium still exposes
            the letter because the link is programmatically focusable — so the
            monogram carries its own, same as the recent strip's. */}}

backend/internal/web/templates/chrome.html

@@ -14,7 +14,7 @@
     <a class="recent-card {{if .HasNewChapter}}is-new{{end}}" href="{{.ContinueURL}}"
        target="_blank" rel="noopener noreferrer">
       <span class="recent-cover">
-        {{if .Cover}}<img src="{{.Cover}}" alt="" loading="lazy">
+        {{if .CoverURL}}<img src="{{.CoverURL}}" alt="" loading="lazy">
         {{else}}<span class="monogram" aria-hidden="true">{{.Initial}}</span>{{end}}
         {{if .HasNewChapter}}<span class="foot-rule"></span>
         {{else if .Favorite}}<span class="foot-rule brass"></span>{{end}}

backend/internal/web/web.go

@@ -50,6 +50,10 @@ type Handler struct {
 	// httpClient is the plain stdlib client that talks to Discord. It is not
 	// an injected interface: tests point APIBase at a stub server instead.
 	httpClient *http.Client
+	// covers proxies kagane cover images, which no browser can load directly.
+	// Nil disables the endpoint — see CoverFetcher.
+	covers     CoverFetcher
+	coverCache coverCache
 }
 
 // listView is what every list-rendering template receives.
@@ -111,7 +115,7 @@ type loginView struct {
 
 // New parses every template up front so a broken one kills the process at
 // startup rather than the first request that touches it.
-func New(s *store.Store, discord DiscordConfig, tokenKey []byte, mangaPath, novelPath string) (*Handler, error) {
+func New(s *store.Store, discord DiscordConfig, tokenKey []byte, mangaPath, novelPath string, covers CoverFetcher) (*Handler, error) {
 	tmpl, err := template.ParseFS(templateFS, "templates/*.html")
 	if err != nil {
 		return nil, err
@@ -126,6 +130,7 @@ func New(s *store.Store, discord DiscordConfig, tokenKey []byte, mangaPath, nove
 		states:              newOAuthStates(),
 		limiter:             session.NewLoginLimiter(),
 		httpClient:          &http.Client{Timeout: discordTimeout},
+		covers:              covers,
 	}, nil
 }
 
@@ -142,6 +147,10 @@ func (h *Handler) Register(mux *http.ServeMux) {
 	mux.HandleFunc("POST /ui/bookmarks/{key}/chapter", h.requireSession(h.uiChapter))
 	mux.HandleFunc("DELETE /ui/bookmarks/{key}", h.requireSession(h.uiDelete))
 
+	// Session-gated like every other UI route: the deployment proxies kagane's
+	// images for its own Readers, not for the internet.
+	mux.HandleFunc("GET /img/kagane/{id}", h.requireSession(h.kaganeCover))
+
 	// Install endpoints render the script directly under the session: the
 	// credential travels inside the served bytes, never in the address bar or
 	// the page markup. Updates after install use the credential-bearing /u/

backend/main.go

@@ -47,6 +47,10 @@ type Config struct {
 	NovelUserscriptPath string
 	// LatestPoll configures the background latest-chapter fetcher.
 	LatestPoll LatestPoll
+	// Covers proxies kagane cover images for the web UI. Not from the
+	// environment: it is the shared headless browser, wired in main once it
+	// connects, and nil in every test router.
+	Covers web.CoverFetcher
 }
 
 // LatestPoll configures the background latest-chapter poller.
@@ -206,7 +210,7 @@ func newRouter(s *store.Store, cfg Config) http.Handler {
 	// The browser UI is always registered; signing in is Discord OAuth, so
 	// there is no password to forget and no gate to leave unset.
 	wh, err := web.New(s, cfg.Discord, []byte(cfg.TokenKey),
-		cfg.UserscriptPath, cfg.NovelUserscriptPath)
+		cfg.UserscriptPath, cfg.NovelUserscriptPath, cfg.Covers)
 	if err != nil {
 		log.Fatalf("web handler: %v", err)
 	}
@@ -270,9 +274,26 @@ func main() {
 	// The poller is off the request path entirely: if it cannot start, the
 	// service still serves bookmarks and the userscript still captures latest
 	// chapters on its own.
+	//
+	// One headless browser serves both consumers that need a Cloudflare
+	// challenge cleared: the poller's kagane/novelfull fetches and the web
+	// UI's kagane cover proxy. Optional — unset leaves both degraded to what
+	// they were before the sidecar existed.
+	var browser latest.Fetcher
 	pollCtx, stopPoll := context.WithCancel(context.Background())
 	defer stopPoll()
-	startLatestPoller(pollCtx, s, cfg.LatestPoll)
+	if ws := strings.TrimSpace(os.Getenv("BROWSER_WS_URL")); ws != "" {
+		bf, err := latest.NewBrowserFetcher(ws)
+		if err != nil {
+			log.Printf("browser fetcher disabled: %v", err)
+		} else {
+			browser = bf
+			cfg.Covers = bf
+			context.AfterFunc(pollCtx, bf.Close)
+			log.Printf("browser fetcher at %s", ws)
+		}
+	}
+	startLatestPoller(pollCtx, s, cfg.LatestPoll, browser)
 
 	srv := &http.Server{
 		Addr:              ":" + cfg.Port,
@@ -307,7 +328,7 @@ func main() {
 // HTTP client cannot be built. Any problem here is logged and skipped: this
 // feature going missing degrades the service to userscript-only latest-chapter
 // tracking, which is exactly how it behaved before.
-func startLatestPoller(ctx context.Context, s *store.Store, cfg LatestPoll) {
+func startLatestPoller(ctx context.Context, s *store.Store, cfg LatestPoll, browser latest.Fetcher) {
 	if !cfg.Enabled {
 		log.Println("latest-chapter poller: disabled by config")
 		return
@@ -317,28 +338,18 @@ func startLatestPoller(ctx context.Context, s *store.Store, cfg LatestPoll) {
 		log.Printf("latest-chapter poller: disabled, cannot build client: %v", err)
 		return
 	}
+	// Nil browser: sites behind a JavaScript challenge are simply not polled,
+	// and their latest_chapter comes from the userscript alone — which is how
+	// the service behaved before the sidecar existed.
 	p := &latest.Poller{
-		Store:    s,
+		Store:        s,
-		Fetch:    f,
+		Fetch:        f,
-		Now:      time.Now,
+		BrowserFetch: browser,
-		Cooldown: cfg.Cooldown,
+		Now:          time.Now,
-		Interval: cfg.Interval,
+		Cooldown:     cfg.Cooldown,
-		Stagger:  cfg.Stagger,
+		Interval:     cfg.Interval,
-		Batch:    cfg.Batch,
+		Stagger:      cfg.Stagger,
-	}
+		Batch:        cfg.Batch,
-
-	// Optional: without it, sites behind a JavaScript challenge are simply not
-	// polled, and their latest_chapter comes from the userscript alone — which
-	// is how the service behaved before the sidecar existed.
-	if ws := strings.TrimSpace(os.Getenv("BROWSER_WS_URL")); ws != "" {
-		bf, err := latest.NewBrowserFetcher(ws)
-		if err != nil {
-			log.Printf("latest-chapter poller: browser fetcher disabled: %v", err)
-		} else {
-			p.BrowserFetch = bf
-			context.AfterFunc(ctx, bf.Close)
-			log.Printf("latest-chapter poller: browser fetcher at %s", ws)
-		}
 	}
 
 	go p.Run(ctx)

chrome/Dockerfile

@@ -0,0 +1,39 @@
+# syntax=docker/dockerfile:1
+
+# Real Google Chrome for the latest-chapter poller and the kagane cover proxy.
+#
+# Not chromedp/headless-shell, which this replaces. headless-shell is a stripped
+# Chrome build and Cloudflare's managed challenge on kagane.to never clears for
+# it: measured 2026-08-08, 60s of a held-open tab still served the interstitial,
+# while stock Chrome from the same IP cleared in ~4s. The tells are structural
+# rather than a header — navigator.webdriver true, an empty plugin list, and
+# Chromium- rather than Chrome-branded client hints. Overriding webdriver alone
+# was tried and did not move it, so the browser build itself is the fix.
+#
+# zenika/alpine-chrome was also tried: its Chrome is 124 (2024), old enough that
+# Cloudflare refuses it outright and old enough to break chromedp's CDP structs.
+FROM debian:trixie-slim
+
+# Chrome is deliberately unpinned, against the usual rule. A pinned build goes
+# stale, and a stale browser is exactly what Cloudflare turns away — the 124 in
+# alpine-chrome is the worked example. Rebuild is the upgrade path.
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends ca-certificates wget gnupg \
+ && wget -qO- https://dl.google.com/linux/linux_signing_key.pub \
+      | gpg --dearmor -o /usr/share/keyrings/google-chrome.gpg \
+ && echo "deb [arch=amd64 signed-by=/usr/share/keyrings/google-chrome.gpg] https://dl.google.com/linux/chrome/deb/ stable main" \
+      > /etc/apt/sources.list.d/google-chrome.list \
+ && apt-get update \
+ && apt-get install -y --no-install-recommends google-chrome-stable socat \
+ && rm -rf /var/lib/apt/lists/*
+
+# Unprivileged: Chrome refuses to run as root, and the CDP endpoint is a shell
+# on whatever user owns it.
+RUN useradd --create-home --shell /usr/sbin/nologin chrome
+USER chrome
+WORKDIR /home/chrome
+
+COPY entrypoint.sh /entrypoint.sh
+
+EXPOSE 9222
+ENTRYPOINT ["/entrypoint.sh"]

chrome/entrypoint.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+set -eu
+
+# A UTC clock is itself the bot signal — Cloudflare treats it as the datacenter
+# default — and kagane's challenge then never clears. Measured 2026-08-08 with
+# an identical container on one Indonesian egress IP: UTC never cleared in 60s
+# (twice), while Asia/Jakarta and America/New_York both cleared in 4s. Any real
+# zone will do; the zone does not have to match the IP's country, it just must
+# not be UTC. It does have to be right the way Chrome reads it.
+#
+# TZ must carry the zone *name*. Chrome resolves the zone through ICU, which
+# takes the name from /etc/localtime's symlink target and ignores the file's
+# contents; bind-mounting the host's /etc/localtime therefore lands on the
+# image's own symlink to Etc/UTC and leaves glibc reporting +07 while Chrome
+# still reports UTC. /etc/timezone, mounted by docker-compose.yml, is the name.
+[ -n "${TZ:-}" ] || TZ=$(cat /etc/timezone 2>/dev/null || echo UTC)
+export TZ
+
+# Chrome's own UA advertises "HeadlessChrome" under --headless=new, and that one
+# token is the difference between kagane.to's challenge clearing in ~4s and
+# never clearing at all (measured 2026-08-08, same host, same Chrome, only the
+# UA changed). Overriding it does not touch the Sec-CH-UA client hints, which
+# report the real version, so the version is read back out of the binary rather
+# than hardcoded: a hardcoded one would drift out of step with the hints on the
+# next Chrome update and become a fresh tell.
+major=$(google-chrome-stable --version | sed -E 's/[^0-9]*([0-9]+)\..*/\1/')
+ua="Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/${major}.0.0.0 Safari/537.36"
+
+# Chrome binds its DevTools port to loopback and silently ignores
+# --remote-debugging-address (verified 2026-08-08: Chrome 151 with
+# --remote-debugging-address=0.0.0.0 still listened on 127.0.0.1 only), so the
+# caller — another container — cannot reach it directly. socat fronting the
+# loopback port is how chromedp/headless-shell solved the same problem and is
+# why this image is a drop-in for it.
+#
+# Nothing publishes 9222; reachability is the `browser` network in
+# docker-compose.yml, and an exposed CDP endpoint is remote code execution.
+socat TCP-LISTEN:9222,fork,reuseaddr TCP:127.0.0.1:9223 &
+
+# Chrome stays in the foreground so that its death takes the container down and
+# compose's restart policy applies; a backgrounded browser behind a live socat
+# would leave the sidecar looking healthy while answering nothing.
+#
+# No --enable-automation: it sets navigator.webdriver, the first thing a bot
+# check reads.
+#
+# --no-sandbox because Chrome's zygote wants user namespaces, which Docker's
+# default profile does not hand out; the alternative is --cap-add=SYS_ADMIN,
+# which gives the container strictly more than it takes away. Containment here
+# is the unprivileged user, the isolated network, and the fact that this
+# browser only ever navigates to kagane.to and novelfull.com.
+exec google-chrome-stable \
+  --headless=new \
+  --no-sandbox \
+  --remote-debugging-port=9223 \
+  --user-agent="$ua" \
+  --user-data-dir=/home/chrome/profile \
+  --no-first-run \
+  --no-default-browser-check \
+  --disable-gpu \
+  about:blank

docker-compose.yml

@@ -24,6 +24,13 @@ services:
       # comes from .env so it is never committed.
       DATABASE_URL: ${DATABASE_URL:-postgres://bookmarks:${POSTGRES_PASSWORD:?set POSTGRES_PASSWORD in .env}@postgres:5432/bookmarks?sslmode=disable}
       PORT: "8080"
+      # Log timestamps only. Go's `log` stamps lines in local time, and this
+      # service has no other use for a zone: bookmark timestamps are unix ms
+      # and the two real time columns are timestamptz, both absolute instants.
+      # Purely so these lines read on the same clock as the sidecar's. Named
+      # API_TZ rather than TZ so an operator's exported shell TZ cannot leak
+      # in; distroless already carries tzdata, so the name just resolves.
+      TZ: ${API_TZ:-Asia/Jakarta}
       # Discord OAuth for the browser UI (ADR-0002). The first four are
       # required; DISCORD_REQUIRED_ROLE is optional and empty by default.
       # Guild membership is the whole gate: any member becomes a Reader.
@@ -95,8 +102,25 @@ services:
       - db
 
   headless-shell:
-    image: chromedp/headless-shell:stable
+    # Real Google Chrome, not chromedp/headless-shell — see chrome/Dockerfile.
+    # The service name is kept so existing overrides and BROWSER_WS_URL stay put.
+    build: ./chrome
+    image: bookmarkmanager-chrome:latest
     restart: unless-stopped
+    environment:
+      # A UTC clock is itself the bot signal: Cloudflare treats it as the
+      # datacenter default, and kagane's challenge then never clears. Measured
+      # 2026-08-08, identical container, one Indonesian egress IP: UTC never
+      # cleared in 60s (twice); Asia/Jakarta and America/New_York both cleared
+      # in 4s. So any real zone works and it need not match the IP's country —
+      # only UTC fails. Unset falls back to the host's /etc/timezone below,
+      # which is a real zone whenever the host clock is set to local time; set
+      # BROWSER_TZ when the host runs UTC.
+      TZ: ${BROWSER_TZ:-}
+    volumes:
+      # The zone *name*, which is what Chrome's ICU needs — see chrome/entrypoint.sh.
+      # Absent on a non-Debian host, which the entrypoint handles by falling back to UTC.
+      - /etc/timezone:/etc/timezone:ro
     # Chrome allocates shared memory per tab and dies on Docker's 64MB default.
     shm_size: '1gb'
     # Reaps zombie renderer processes, which otherwise accumulate for the
@@ -104,17 +128,8 @@ services:
     init: true
     # Deliberately no `ports:` — an exposed CDP endpoint is remote code
     # execution. Only bookmark-api, via the `browser` network below, may reach it.
-    # Don't pass --remote-debugging-address/--remote-debugging-port here: the
+    # No `command:` either: every flag this browser needs is in its entrypoint,
-    # image's own entrypoint (/headless-shell/run.sh) already starts Chrome on
+    # and the UA override there is load-bearing for the challenge.
-    # 127.0.0.1:9223 and fronts it with a socat proxy listening on 0.0.0.0:9222.
-    # Redeclaring the port flag here overrides Chrome's, so it binds 9222
-    # directly (IPv6 loopback only) instead of 9223 — collides with socat's own
-    # bind on 9222 and leaves nothing listening on 9223, so every external
-    # connection to headless-shell:9222 fails with EOF. Only pass flags the
-    # entrypoint doesn't already set.
-    command:
-      - --disable-gpu
-      - --no-sandbox
     networks:
       browser:
         # Pinned so BROWSER_WS_URL can name an IP (required, see above) that

userscript/AGENTS.md

@@ -44,6 +44,25 @@ Guidance for OpenCode (and Claude Code) working under `userscript/`. See root `A
   Encodings (incl. triple-encoded punctuation like `%25252D`) identical
   on /manga/ and /title/ pages, so decode-once seriesIds match — verified
   2026-07-28.
+- **comix.to**: series `/title/<id>-<slug>`, chapter
+  `/title/<id>-<slug>/<uploadId>-chapter-<n>`. Only the leading `<id>` is
+  identity — the slug re-renders when a series is renamed (`comixSeriesId`).
+  An SPA that **never rewrites `og:title`**: the server-rendered head keeps
+  whatever document loaded first, so on a cold load `og:title` is the homepage's
+  "Comix — Read Comics online for free" and after an in-page hop it is the
+  *previous* series' name. `document.title` is the one thing client routing does
+  update, so titles come from there, with the chapter page's `" · Ch.<n>"` tail
+  stripped. Covers likewise: `og:image` is absent, so the cover is the `img`
+  whose `alt` matches the cleaned title — verified live 2026-08-08.
+- **kagane.to**: series `/series/<uuid>`, reader
+  `/series/<uuid>/reader/<bookUuid>`. Reader URLs carry no chapter number, so
+  the number comes out of `og:title`. Two shapes exist: `"<Series> - Chapter
+  <n>[ - Episode <n>]"` and, for volume-numbered series, `"<Series> - Volume <v>
+  Chapter <n>"` with no episode name — both must yield a bare series title, or
+  the volume tail lands in the bookmark's title. Its covers are challenge- and
+  CORP-protected, so the web UI proxies them; the userscript still stores the
+  raw `og:image`. Behind a Cloudflare JS challenge, so the backend polls it
+  through the headless browser.
 - **novelfull.com** (novel script): series `/<slug>.html`, chapter
   `/<slug>/chapter-<n>[-<title-slug>].html`. No `og:*` tags at all — title from
   `h3.title` (series) or `a.truyen-title` (chapter), cover from

userscript/manga-bookmark.user.js

@@ -242,6 +242,12 @@
     matches: (loc) => /(^|\.)comix\.to$/.test(loc.hostname),
     detect(loc) {
       const path = loc.pathname;
+      // comix client-routes without ever rewriting og:title — the head keeps
+      // whatever the first server-rendered document carried, so a bookmark
+      // taken after a client route got the homepage's title, then the
+      // previous series'. document.title is the one thing its router does
+      // update. Verified live 2026-08-08; do not "restore" meta("og:title").
+      const pageTitle = cleanTitle(document.title);
       // /title/<id>-<slug>/<uploadId>-chapter-<n>. Several uploads (different
       // groups or languages) share one chapter number; the number is the
       // progress identity, the upload id is not.
@@ -252,8 +258,8 @@
           type: "chapter",
           site: this.site,
           seriesId: comixSeriesId(m[1]),
-          title: cleanTitle(meta("og:title")),
+          title: pageTitle,
-          cover: coverFromPage(),
+          cover: coverFromPage(pageTitle),
           seriesUrl: loc.origin + "/title/" + m[1],
           chapterLabel: "Chapter " + m[2],
           chapterNum: isNaN(num) ? null : num,
@@ -267,8 +273,8 @@
           type: "series",
           site: this.site,
           seriesId: comixSeriesId(m[1]),
-          title: cleanTitle(meta("og:title")),
+          title: pageTitle,
-          cover: coverFromPage(),
+          cover: coverFromPage(pageTitle),
           seriesUrl: loc.origin + "/title/" + m[1],
           chapterLabel: null,
           chapterNum: null,
@@ -277,7 +283,7 @@
       }
       return { type: "other" };
 
-      // comix chapter og:title is "<Title> · Ch.<n>"; series is clean.
+      // comix chapter document.title is "<Title> · Ch.<n>"; series is clean.
       function cleanTitle(t) {
         if (!t) return "";
         return t.replace(/\s*·\s*Ch\.[\d.]+\s*$/i, "").trim();
@@ -287,8 +293,7 @@
       // the DOM for a cover. Matching on alt rather than a class keeps it off
       // the site's styling: the cover is the image whose alt is the title.
       // Do not "simplify" this into meta("og:image") — that returns null.
-      function coverFromPage() {
+      function coverFromPage(title) {
-        const title = cleanTitle(meta("og:title"));
         if (!title || !document.querySelectorAll) return "";
         for (const img of document.querySelectorAll("img[alt]")) {
           if (img.getAttribute("alt") === title) return img.getAttribute("src") || "";
@@ -313,6 +318,14 @@
     },
   };
 
+  // Kagane builds the reader og:title suffix out of the book's metadata, so
+  // every combination occurs: the volume part appears only when the book has a
+  // volume_no, the episode part only when it has a non-empty title. All four
+  // shapes captured live 2026-08-08 — "SP Baby - Volume 1 Chapter 1" is the one
+  // the old trailing-space regex missed, which left both the number and the
+  // series title wrong.
+  const KAGANE_CHAPTER_SUFFIX = /\s-\s(?:Volume\s[\d.]+\s)?Chapter\s([\d.]+)(?:\s-\s.*)?$/i;
+
   const kagane = {
     site: "kagane",
     matches: (loc) => /(^|\.)kagane\.to$/.test(loc.hostname),
@@ -353,9 +366,8 @@
       }
       return { type: "other" };
 
-      // Reader og:title is "<Title> - Chapter <n> - <episode name>".
       function chapterNumFromTitle(t) {
-        const m = t && t.match(/\s-\sChapter\s([\d.]+)\s/);
+        const m = t && t.match(KAGANE_CHAPTER_SUFFIX);
         if (!m) return null;
         const num = parseFloat(m[1]);
         return isNaN(num) ? null : num;
@@ -363,7 +375,7 @@
 
       function cleanTitle(t) {
         if (!t) return "";
-        return t.replace(/\s-\sChapter\s[\d.]+\s-\s.*$/i, "").trim();
+        return t.replace(KAGANE_CHAPTER_SUFFIX, "").trim();
       }
     },
     // Reader hrefs are uuids with no number in them, so no maximum can be taken
@@ -1450,8 +1462,15 @@
   }
 
   let lastUrl = location.href;
-  function onNavigate() {
+  let lastPageSig = "";
+
+  function setPage() {
     state.page = detect();
+    lastPageSig = JSON.stringify(state.page);
+  }
+
+  function onNavigate() {
+    setPage();
     render();
     maybeAutoUpdate();
     maybeCaptureLatestOnSeriesPage();
@@ -1484,7 +1503,14 @@
     wrap("pushState");
     wrap("replaceState");
     window.addEventListener("popstate", fire);
-    setInterval(fire, 1500); // catch routes that bypass history
+    // Also catches routes that bypass history — and comix, which fills
+    // document.title a beat after the route changes, so the 300ms snapshot
+    // above can still hold the previous page's title. Re-detect whenever what
+    // we would read has changed, not only when the URL has.
+    setInterval(() => {
+      fire();
+      if (JSON.stringify(detect()) !== lastPageSig) onNavigate();
+    }, 1500);
   }
 
   // ============================================================
@@ -1563,7 +1589,7 @@
 
   function init() {
     buildUI();
-    state.page = detect();
+    setPage();
     render();
     installNavWatcher();
     installLongPress();

userscript/test/logic.test.js

@@ -31,6 +31,9 @@ globalThis.location = {
 
 // og: meta tags the adapters read through meta(). Reassigned per test.
 let metaTags = {};
+// document.title. comix's SPA rewrites this on client routing but never
+// og:title, so the comix adapter reads it instead. Reassigned per test.
+let docTitle = "";
 // img[alt] elements comix's coverFromPage() scans. Reassigned per test; each
 // entry is {alt, src}.
 let pageImages = [];
@@ -48,6 +51,9 @@ globalThis.document = {
     }));
   },
   addEventListener() {},
+  get title() {
+    return docTitle;
+  },
   body: undefined,
 };
 
@@ -193,8 +199,15 @@ test("comixSeriesId leaves a bare id untouched", () => {
   assert.equal(comixSeriesId("n8we"), "n8we");
 });
 
+// comix is an SPA that rewrites document.title on client routing but leaves the
+// server-rendered og:title untouched, so every test here pins og:title to a
+// STALE value — the homepage title on first hop, the previous series after
+// that. Captured live 2026-08-08.
+const COMIX_STALE_HOME = "Comix - Read Comics online for free";
+
 test("comix detects a series page", () => {
-  metaTags = { "og:title": "Dungeons and Crayons" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons";
   const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
   assert.equal(p.type, "series");
   assert.equal(p.site, "comix");
@@ -204,8 +217,16 @@ test("comix detects a series page", () => {
   assert.equal(p.chapterNum, null);
 });
 
+test("comix ignores a previous series' stale og:title", () => {
+  metaTags = { "og:title": "Full-Time Awakening" };
+  docTitle = "Dungeons and Crayons";
+  const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
+  assert.equal(p.title, "Dungeons and Crayons");
+});
+
 test("comix detects a chapter page and strips the Ch. suffix from the title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons · Ch.80";
   const p = comix.detect(
     loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80")
   );
@@ -218,7 +239,8 @@ test("comix detects a chapter page and strips the Ch. suffix from the title", ()
 });
 
 test("comix parses decimal chapter numbers", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80.5" };
+  metaTags = {};
+  docTitle = "Dungeons and Crayons · Ch.80.5";
   const p = comix.detect(
     loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80.5")
   );
@@ -226,19 +248,19 @@ test("comix parses decimal chapter numbers", () => {
 });
 
 test("comix.detect reads the cover from an img whose alt matches the cleaned title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons · Ch.80" };
+  metaTags = { "og:title": COMIX_STALE_HOME };
+  docTitle = "Dungeons and Crayons";
   pageImages = [
     { alt: "Some Other Series", src: "https://cdn.example/other.jpg" },
     { alt: "Dungeons and Crayons", src: "https://cdn.example/cover.jpg" },
   ];
-  const p = comix.detect(
+  const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
-    loc("https://comix.to/title/n8we-dungeons-and-crayons/11139891-chapter-80")
-  );
   assert.equal(p.cover, "https://cdn.example/cover.jpg");
 });
 
 test("comix.detect leaves cover empty when no img alt matches the title", () => {
-  metaTags = { "og:title": "Dungeons and Crayons" };
+  metaTags = {};
+  docTitle = "Dungeons and Crayons";
   pageImages = [{ alt: "Some Other Series", src: "https://cdn.example/other.jpg" }];
   const p = comix.detect(loc("https://comix.to/title/n8we-dungeons-and-crayons"));
   assert.equal(p.cover, "");
@@ -315,6 +337,33 @@ test("kagane reads the chapter number out of og:title", () => {
   assert.equal(p.seriesUrl, "https://kagane.to/series/" + KAGANE_SERIES);
 });
 
+// Volume-numbered series render the suffix as "- Volume <v> Chapter <n>" with
+// no episode name, because the book carries volume_no and an empty title.
+// Captured live 2026-08-08 from SP Baby.
+test("kagane reads through a Volume-numbered chapter suffix", () => {
+  metaTags = {
+    "og:title": "SP Baby - Volume 1 Chapter 1",
+    "og:image": "https://kagane.to/api/v2/image/abc/compressed",
+  };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.title, "SP Baby");
+  assert.equal(p.chapterNum, 1);
+  assert.equal(p.chapterLabel, "Chapter 1");
+});
+
+// A book with neither a volume nor an episode name ends the title right after
+// the number, which the old trailing-\s regex could not match.
+test("kagane reads a chapter suffix with no episode name", () => {
+  metaTags = { "og:title": "Some Series - Chapter 7.5" };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.title, "Some Series");
+  assert.equal(p.chapterNum, 7.5);
+});
+
 test("kagane yields a null chapterNum when og:title has no chapter", () => {
   metaTags = { "og:title": "Infinite Decryption: The Strongest Level 0" };
   const p = kagane.detect(