During testing, we discovered that when a user requests the agent to
send a file (e.g., "send me IMG_1115.png"), the agent would call
read_file to view the content and then reply with text claiming
"file sent" — but never actually deliver the file to the user.
Root cause: The system prompt stated "Reply directly with text for
conversations. Only use the 'message' tool to send to a specific
chat channel", which led the LLM to believe text replies were
sufficient for all responses, including file delivery.
Fix: Add an explicit IMPORTANT instruction in the system prompt
telling the LLM it MUST use the 'message' tool with the 'media'
parameter to send files, and that read_file only reads content
for its own analysis.
Co-Authored-By: qulllee <qullkui@tencent.com>
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