diff --git a/tests/tools/test_web_result_cache.py b/tests/tools/test_web_result_cache.py
index 0f28132a07..94db38651b 100644
--- a/tests/tools/test_web_result_cache.py
+++ b/tests/tools/test_web_result_cache.py
@@ -196,6 +196,36 @@ def test_extract_cache_oversized_page_not_indexed(_isolated_cache):
     assert extract_cache_get("https://big.com") is None
 
 
+@pytest.mark.parametrize("url", [
+    "http://localhost:3000/app",
+    "http://localhost:5173",             # vite dev server
+    "http://127.0.0.1:8080/preview",
+    "http://[::1]:3000/",
+    "http://192.168.1.44/dashboard",
+    "http://10.0.0.5:8000/api/docs",
+    "http://172.16.0.9/",
+    "http://myapp.local/",
+    "http://devbox/page",                # single-label LAN name
+    "http://preview.localhost/artifact",
+])
+def test_extract_cache_never_caches_local_dev_urls(url, _isolated_cache):
+    """Local/private URLs are dev servers and chat-GUI artifact previews —
+    they change on every save, so freshness beats dedup. Neither put nor
+    get may touch the cache for them."""
+    extract_cache_put(url, "stale build output")
+    assert extract_cache_get(url) is None
+
+
+@pytest.mark.parametrize("url", [
+    "https://example.com/page",
+    "https://docs.python.org/3/",
+])
+def test_extract_cache_public_urls_still_cache(url, _isolated_cache):
+    extract_cache_put(url, "public content")
+    hit = extract_cache_get(url)
+    assert hit is not None and hit["content"] == "public content"
+
+
 def test_extract_cache_tampered_index_path_is_miss(_isolated_cache, tmp_path):
     """An index entry pointing outside cache/web must never be read."""
     outside = tmp_path / "outside.md"
diff --git a/tools/web_result_cache.py b/tools/web_result_cache.py
index 9799e34612..d5b8371e38 100644
--- a/tools/web_result_cache.py
+++ b/tools/web_result_cache.py
@@ -275,6 +275,43 @@ def _entry_file_path(url: str, format: Optional[str], provider: str) -> Optional
     return d / f"{slug}-{_url_digest(url, format, provider)}.cache.md"
 
 
+def _is_local_dev_url(url: str) -> bool:
+    """True for loopback/private/LAN URLs — never cached.
+
+    A page on a private address is one the user controls and is typically
+    changing fast (dev servers, hot reload, chat-GUI artifact previews,
+    LAN preview apps). Freshness is the point of fetching it, so the cache
+    declines these entirely rather than serving a stale build for a whole
+    TTL. Only reachable when ``security.allow_private_urls`` is enabled —
+    default installs SSRF-block these URLs before extraction anyway.
+
+    Hostname heuristics only (no DNS resolution — this is a freshness
+    decision, not a security boundary; SSRF enforcement lives in
+    tools/url_safety.py).
+    """
+    try:
+        from urllib.parse import urlparse
+        host = (urlparse(url).hostname or "").strip("[]").lower()
+        if not host:
+            return True  # unparseable → don't cache
+        if host == "localhost" or host.endswith(".localhost") or host.endswith(".local"):
+            return True
+        # Single-label hostnames (no dot) are LAN names, not public DNS.
+        if "." not in host and ":" not in host:
+            return True
+        import ipaddress
+        try:
+            ip = ipaddress.ip_address(host)
+        except ValueError:
+            return False  # public DNS name
+        return bool(
+            ip.is_private or ip.is_loopback or ip.is_link_local
+            or ip.is_reserved or ip.is_unspecified
+        )
+    except Exception:  # noqa: BLE001 — on doubt, don't cache
+        return True
+
+
 def extract_cache_get(
     url: str,
     format: Optional[str] = None,
@@ -283,6 +320,8 @@ def extract_cache_get(
     """Return {'url','title','content'} for a fresh cached page, else None."""
     if not cache_enabled():
         return None
+    if _is_local_dev_url(url):
+        return None
     with _index_lock:
         index = _load_index()
         entry = index.get(_url_digest(url, format, provider))
@@ -327,6 +366,8 @@ def extract_cache_put(
     """
     if not cache_enabled() or not content:
         return
+    if _is_local_dev_url(url):
+        return
     try:
         from tools.web_tools import MAX_STORED_TEXT_CHARS
         if len(content) > MAX_STORED_TEXT_CHARS:
diff --git a/website/docs/user-guide/features/web-search.md b/website/docs/user-guide/features/web-search.md
index ceda417248..a90c69bfab 100644
--- a/website/docs/user-guide/features/web-search.md
+++ b/website/docs/user-guide/features/web-search.md
@@ -75,6 +75,8 @@ Concurrent identical searches (a parallel subagent fan-out firing the same query
 
 Only successful responses are cached. Failures always retry the backend, responses served by the one-shot keyless rescue are never cached (the next call attempts your chosen backend again), and URLs matched by your `security.website_blocklist` are never served from cache. Cached extracts re-run the normal truncation pipeline, so a different `char_limit` on the second call works off the same stored scrape.
 
+**Local development URLs are never cached.** Anything on `localhost`, `127.0.0.1`, `*.local`, single-label LAN hostnames, or private/link-local IP ranges (`192.168.*`, `10.*`, `172.16-31.*`) bypasses the extract cache entirely — dev servers, hot-reload builds, and chat-GUI artifact previews change on every save, and a cached copy would show you a stale build. Every fetch of a local page is live. (These URLs are only reachable at all when `security.allow_private_urls` is enabled.)
+
 ```yaml
 # ~/.hermes/config.yaml
 web: