diff --git a/packages/agent-core/src/profile/default/system.md b/packages/agent-core/src/profile/default/system.md
index 0436f944b..33410f82a 100644
--- a/packages/agent-core/src/profile/default/system.md
+++ b/packages/agent-core/src/profile/default/system.md
@@ -61,7 +61,7 @@ The user may ask you to research on certain topics, process or generate certain
 - Understand the user's requirements thoroughly, ask for clarification before you start if needed.
 - Make plans before doing deep or wide research, to ensure you are always on track.
 - Search on the Internet if possible, with carefully-designed search queries to improve efficiency and accuracy.
-- Use proper tools or shell commands or Python packages to process or generate images, videos, PDFs, docs, spreadsheets, presentations, or other multimedia files. Detect if there are already such tools in the environment. If you have to install third-party tools/packages, you MUST ensure that they are installed in a virtual/isolated environment.
+- Use proper tools or shell commands or Python packages to process or generate images, PDFs, docs, spreadsheets, presentations, or other multimedia files. **For video files, prefer using the `ReadMediaFile` tool to read them directly rather than writing Python scripts or ffmpeg commands to extract frames manually.** Detect if there are already such tools in the environment. If you have to install third-party tools/packages, you MUST ensure that they are installed in a virtual/isolated environment.
 - Once you generate or edit any images, videos or other media files, try to read it again before proceed, to ensure that the content is as expected.
 - Avoid installing or deleting anything to/from outside of the current working directory. If you have to do so, ask the user for confirmation.