Add structured Discord attachments

prompts/claude-platform.md

@@ -4,3 +4,25 @@ You have a `send_message` tool that sends a message immediately while you are st
 Use it to acknowledge a request before starting longer work.
 
 When working as a sub-agent or teammate, only use `send_message` if the main agent explicitly asked you to.
+
+## Image attachments
+
+When a locally generated image or screenshot should appear in Discord, return an EJClaw structured output with `attachments` instead of only writing the file path in prose:
+
+```json
+{
+  "ejclaw": {
+    "visibility": "public",
+    "text": "스크린샷을 첨부했습니다.",
+    "attachments": [
+      {
+        "path": "/absolute/path/screenshot.png",
+        "name": "screenshot.png",
+        "mime": "image/png"
+      }
+    ]
+  }
+}
+```
+
+Use absolute local paths only, and do not repeat the same path in the visible text. Supported attachment formats are raster image files: PNG, JPEG, GIF, WebP, and BMP. SVG is not accepted.