diff --git a/backend/packages/harness/deerflow/utils/AGENTS.md b/backend/packages/harness/deerflow/utils/AGENTS.md
index f7f79f588..0bc17cbca 100644
--- a/backend/packages/harness/deerflow/utils/AGENTS.md
+++ b/backend/packages/harness/deerflow/utils/AGENTS.md
@@ -18,3 +18,10 @@ Tool and agent assembly re-enters `get_available_tools()` and may block on MCP d
 optional leading UTF-8 BOM cannot hide a first-line heading or code fence, or
 occupy a preview line. Preserve physical line numbers, embedded U+FEFF
 characters, and the original file bytes.
+
+### Active Content MIME Types
+
+`text_detection.py::_is_active_content_mime_type` is the shared download-safety
+boundary for artifacts and project documents. Keep platform aliases such as
+Windows' `image/svg` aligned with their standard active type (`image/svg+xml`),
+and preserve the generic `+xml` rule.
diff --git a/backend/packages/harness/deerflow/utils/text_detection.py b/backend/packages/harness/deerflow/utils/text_detection.py
index e74f4df8a..83a9ce662 100644
--- a/backend/packages/harness/deerflow/utils/text_detection.py
+++ b/backend/packages/harness/deerflow/utils/text_detection.py
@@ -16,11 +16,12 @@ def is_text_file_by_content(path: Path, sample_size: int = 8192) -> bool:
         return False
 
 
-# Exact matches only; ``_is_active_content_mime_type`` also treats every
+# Exact matches include platform MIME aliases; the helper also treats every
 # ``+xml`` subtype as active content.
 ACTIVE_CONTENT_MIME_TYPES = {
     "text/html",
     "application/xhtml+xml",
+    "image/svg",
     "image/svg+xml",
     "text/xml",
     "application/xml",
@@ -32,10 +33,10 @@ def _is_active_content_mime_type(mime_type: str | None) -> bool:
     """Return whether a browser can run script when rendering *mime_type* inline.
 
     Beyond HTML, this covers every WHATWG XML MIME type (``text/xml``,
-    ``application/xml``, or a ``+xml`` subtype) plus ``text/xsl``, which Blink
-    also renders as XML: any XML document can carry an XHTML-namespaced
-    ``<script>``, so ``report.xml`` or ``feed.rss`` is as dangerous as
-    ``page.html`` when opened in the application origin.
+    ``application/xml``, or a ``+xml`` subtype), Windows' ``image/svg`` alias,
+    and ``text/xsl``, which Blink also renders as XML: any XML document can
+    carry an XHTML-namespaced ``<script>``, so ``report.xml`` or ``feed.rss``
+    is as dangerous as ``page.html`` when opened in the application origin.
     """
     if mime_type is None:
         return False
diff --git a/backend/tests/test_artifacts_router.py b/backend/tests/test_artifacts_router.py
index 97a6e898d..72b3c028f 100644
--- a/backend/tests/test_artifacts_router.py
+++ b/backend/tests/test_artifacts_router.py
@@ -626,6 +626,7 @@ def test_get_artifact_forces_download_for_any_xml_subtype(tmp_path, monkeypatch,
         "text/html",
         "application/xhtml+xml",
         "image/svg+xml",
+        "image/svg",
         "text/xml",
         "application/xml",
         "text/xsl",
@@ -636,8 +637,8 @@ def test_get_artifact_forces_download_for_any_xml_subtype(tmp_path, monkeypatch,
     ],
 )
 def test_is_active_content_mime_type_covers_html_and_xml_documents(mime_type: str) -> None:
-    # Whether .rss or .atom guess to a +xml type depends on the host's
-    # mime.types file, so the classification is pinned on MIME types directly.
+    # MIME guesses depend on the host database (Windows uses image/svg), so
+    # classification is pinned on MIME types directly.
     assert artifacts_router._is_active_content_mime_type(mime_type)