fix: 429 retry, sequential batching, force UI refresh after prescreen

1. prescreener.py: classify_with_deepseek now retries on 429 with
   exponential back-off (5s → 10s → 20s → 40s, up to 4 attempts);
   same back-off also covers other transient errors.

2. main.py: prescreen batches run sequentially with a 3s gap instead
   of asyncio.gather (parallel). Parallel batches caused the second
   batch to always hit the 429 rate limit, leaving most domains
   unclassified (only the smaller last batch succeeded).

3. index.html: prescreenSelected() now clears this.domains before
   calling _fetch() so Alpine re-renders the full table with the
   updated niche/type values; also updates the notify hint to mention
   the expected 1-2 min wait.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/main.py

@@ -196,17 +196,17 @@ async def prescreen_batch(body: dict):
         counts[s] = counts.get(s, 0) + 1
 
     # Phase 2: DeepSeek classification for live sites only
+    # Run batches sequentially — parallel requests cause 429 rate-limit errors.
     live = [r for r in results if r.get("prescreen_status") == "live"]
     classified = 0
     if live:
         batches = [live[i:i + DEEPSEEK_BATCH_SIZE] for i in range(0, len(live), DEEPSEEK_BATCH_SIZE)]
-        batch_cls = await asyncio.gather(
-            *[classify_with_deepseek(b) for b in batches], return_exceptions=True
-        )
         all_cls: list = []
-        for bc in batch_cls:
-            if isinstance(bc, list):
-                all_cls.extend(bc)
+        for i, batch in enumerate(batches):
+            if i > 0:
+                await asyncio.sleep(3)   # brief gap between batches
+            cls = await classify_with_deepseek(batch)
+            all_cls.extend(cls)
         if all_cls:
             await save_prescreen_results(all_cls)
             classified = len(all_cls)

app/prescreener.py

@@ -223,8 +223,9 @@ def _parse_classify_output(raw: str) -> list[dict]:
 async def classify_with_deepseek(live_items: list[dict]) -> list[dict]:
     """Single DeepSeek call → list of {domain, niche, type}.
 
-    Replicate may return 202 (async) for slow models like DeepSeek-R1.
-    We poll the prediction URL until it succeeds or times out.
+    Handles:
+    - 429 Too Many Requests: exponential back-off, up to 4 retries
+    - 202 Accepted (async prediction): polls urls.get until succeeded
     """
     if not live_items:
         return []
@@ -235,36 +236,42 @@ async def classify_with_deepseek(live_items: list[dict]) -> list[dict]:
             "temperature": 0.1,
         }
     }
-    auth_headers = {
-        "Authorization": f"Bearer {REPLICATE_TOKEN}",
-        "Content-Type": "application/json",
-    }
+    auth_header = {"Authorization": f"Bearer {REPLICATE_TOKEN}"}
+
+    MAX_RETRIES = 4
+    for attempt in range(MAX_RETRIES):
         try:
             async with httpx.AsyncClient(timeout=300) as client:
                 resp = await client.post(
                     DEEPSEEK_MODEL,
-                headers={**auth_headers, "Prefer": "wait=60"},
+                    headers={**auth_header, "Content-Type": "application/json", "Prefer": "wait=60"},
                     json=payload,
                 )
+
+                # ── Retry on rate-limit ──────────────────────────────────────
+                if resp.status_code == 429:
+                    wait = min(60, 5 * (2 ** attempt))   # 5 → 10 → 20 → 40s
+                    logger.warning("DeepSeek 429 (attempt %d/%d), retrying in %ds",
+                                   attempt + 1, MAX_RETRIES, wait)
+                    await asyncio.sleep(wait)
+                    continue
+
                 resp.raise_for_status()
                 data = resp.json()
 
-            # ── Poll if Replicate accepted async (202 or status starting/processing) ──
+                # ── Poll if Replicate queued async (202) ─────────────────────
                 if resp.status_code == 202 or data.get("status") in ("starting", "processing"):
                     poll_url = (data.get("urls") or {}).get("get")
                     if not poll_url:
                         logger.error("DeepSeek: 202 but no poll URL in response")
                         return []
                     logger.info("DeepSeek: async prediction, polling %s", poll_url)
-                for attempt in range(90):          # up to ~3 minutes
+                    for tick in range(90):          # up to ~3 minutes
                         await asyncio.sleep(2)
-                    pr = await client.get(
-                        poll_url,
-                        headers={"Authorization": f"Bearer {REPLICATE_TOKEN}"},
-                    )
+                        pr = await client.get(poll_url, headers=auth_header)
                         pdata = pr.json()
                         status = pdata.get("status")
-                    logger.debug("DeepSeek poll #%d status=%s", attempt + 1, status)
+                        logger.debug("DeepSeek poll #%d status=%s", tick + 1, status)
                         if status == "succeeded":
                             data = pdata
                             break
@@ -272,9 +279,10 @@ async def classify_with_deepseek(live_items: list[dict]) -> list[dict]:
                             logger.error("DeepSeek prediction %s: %s", status, pdata.get("error"))
                             return []
                     else:
-                    logger.error("DeepSeek: prediction timed out after polling 90×2s")
+                        logger.error("DeepSeek: prediction timed out after 90 polls")
                         return []
 
+            # ── Parse output ─────────────────────────────────────────────────
             output = data.get("output") or ""
             if isinstance(output, list):
                 output = "".join(str(t) for t in output if t is not None)
@@ -285,5 +293,12 @@ async def classify_with_deepseek(live_items: list[dict]) -> list[dict]:
             return result
 
         except Exception as e:
-        logger.error("DeepSeek classification error: %s", e)
+            if attempt < MAX_RETRIES - 1:
+                wait = 5 * (2 ** attempt)
+                logger.warning("DeepSeek error (attempt %d/%d), retry in %ds: %s",
+                               attempt + 1, MAX_RETRIES, wait, e)
+                await asyncio.sleep(wait)
+            else:
+                logger.error("DeepSeek classification failed after %d attempts: %s",
+                             MAX_RETRIES, e)
     return []

app/static/index.html

@@ -773,7 +773,8 @@ function app() {
     async prescreenSelected() {
       if(!this.selected.length || this.prescreening) return;
       this.prescreening = true;
-      this.notify(`Pre-screening ${this.selected.length} domains… (may take ~30s)`, 'info');
+      const count = this.selected.length;
+      this.notify(`Pre-screening ${count} domains… (DeepSeek classification may take 1-2 min)`, 'info');
       try {
         const r = await fetch('/api/prescreen/batch', {
           method: 'POST',
@@ -786,7 +787,10 @@ function app() {
             `✅ ${d.live} live · 🅿 ${d.parked} parked · ↗ ${d.redirect} redirect · ☠ ${d.dead} dead · 🏷 ${d.classified} classified`,
             'success'
           );
-          await this._fetch(); // refresh to show niche/type columns
+          this.selected = [];
+          // Force full re-fetch of current page to show updated niche/type
+          this.domains = [];
+          await this._fetch();
         } else {
           this.notify('Error: ' + (d.error||'unknown'), 'error');
         }